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2023-11-06mm/zsmalloc: Replace bit spinlock and get_cpu_var() usage.Mike Galbraith2-8/+79
For efficiency reasons, zsmalloc is using a slim `handle'. The value is the address of a memory allocation of 4 or 8 bytes depending on the size of the long data type. The lowest bit in that allocated memory is used as a bit spin lock. The usage of the bit spin lock is problematic because with the bit spin lock held zsmalloc acquires a rwlock_t and spinlock_t which are both sleeping locks on PREEMPT_RT and therefore must not be acquired with disabled preemption. Extend the handle to struct zsmalloc_handle which holds the old handle as addr and a spinlock_t which replaces the bit spinlock. Replace all the wrapper functions accordingly. The usage of get_cpu_var() in zs_map_object() is problematic because it disables preemption and makes it impossible to acquire any sleeping lock on PREEMPT_RT such as a spinlock_t. Replace the get_cpu_var() usage with a local_lock_t which is embedded struct mapping_area. It ensures that the access the struct is synchronized against all users on the same CPU. This survived LTP testing. Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [bigeasy: replace the bitspin_lock() with a mutex, get_locked_var() and patch description. Mike then fixed the size magic and made handle lock spinlock_t.] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
2023-11-06mm/vmalloc: Another preempt disable region which sucksThomas Gleixner1-5/+8
Avoid the preempt disable version of get_cpu_var(). The inner-lock should provide enough serialisation. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2023-11-06mm: workingset: replace IRQ-off check with a lockdep assert.Sebastian Andrzej Siewior1-1/+4
Commit 68d48e6a2df57 ("mm: workingset: add vmstat counter for shadow nodes") introduced an IRQ-off check to ensure that a lock is held which also disabled interrupts. This does not work the same way on -RT because none of the locks, that are held, disable interrupts. Replace this check with a lockdep assert which ensures that the lock is held. Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190211113829.sqf6bdi4c4cdd3rp@linutronix.de
2023-11-06sched: Remove preempt_offset argument from __might_sleep()Thomas Gleixner1-1/+1
All callers hand in 0 and never will hand in anything else. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lore.kernel.org/r/20210923165358.054321586@linutronix.de
2023-11-06mm: Disable NUMA_BALANCING_DEFAULT_ENABLED and TRANSPARENT_HUGEPAGE on ↵Sebastian Andrzej Siewior1-1/+1
PREEMPT_RT TRANSPARENT_HUGEPAGE: There are potential non-deterministic delays to an RT thread if a critical memory region is not THP-aligned and a non-RT buffer is located in the same hugepage-aligned region. It's also possible for an unrelated thread to migrate pages belonging to an RT task incurring unexpected page faults due to memory defragmentation even if khugepaged is disabled. Regular HUGEPAGEs are not affected by this can be used. NUMA_BALANCING: There is a non-deterministic delay to mark PTEs PROT_NONE to gather NUMA fault samples, increased page faults of regions even if mlocked and non-deterministic delays when migrating pages. [Mel Gorman worded 99% of the commit description]. Link: https://lore.kernel.org/all/20200304091159.GN3818@techsingularity.net/ Link: https://lore.kernel.org/all/20211026165100.ahz5bkx44lrrw5pt@linutronix.de/ Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Mel Gorman <mgorman@techsingularity.net> Link: https://lore.kernel.org/r/20211028143327.hfbxjze7palrpfgp@linutronix.de
2023-11-06mm: page_alloc: Use migrate_disable() in drain_local_pages_wq()Sebastian Andrzej Siewior1-2/+2
drain_local_pages_wq() disables preemption to avoid CPU migration during CPU hotplug and can't use cpus_read_lock(). Using migrate_disable() works here, too. The scheduler won't take the CPU offline until the task left the migrate-disable section. The problem with disabled preemption here is that drain_local_pages() acquires locks which are turned into sleeping locks on PREEMPT_RT and can't be acquired with disabled preemption. Use migrate_disable() in drain_local_pages_wq(). Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lore.kernel.org/r/20211015210933.viw6rjvo64qtqxn4@linutronix.de
2023-11-06mm: Disable zsmalloc on PREEMPT_RTSebastian Andrzej Siewior1-1/+2
For efficiency reasons, zsmalloc is using a slim `handle'. The value is the address of a memory allocation of 4 or 8 bytes depending on the size of the long data type. The lowest bit in that allocated memory is used as a bit spin lock. The usage of the bit spin lock is problematic because with the bit spin lock held zsmalloc acquires a rwlock_t and spinlock_t which are both sleeping locks on PREEMPT_RT and therefore must not be acquired with disabled preemption. There is a patch which extends the handle on PREEMPT_RT so that a full spinlock_t fits (even with lockdep enabled) and then eliminates the bit spin lock. I'm not sure how sensible zsmalloc on PREEMPT_RT is given that it is used to store compressed user memory. Disable ZSMALLOC on PREEMPT_RT. If there is need for it, we can try to get it to work. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lkml.kernel.org/r/20210923170121.1860133-1-bigeasy@linutronix.de
2023-07-10mm: page_alloc: fix building error on -Werror=array-compareXiongwei Song1-1/+1
Arthur Marsh reported we would hit the error below when building kernel with gcc-12: CC mm/page_alloc.o mm/page_alloc.c: In function `mem_init_print_info': mm/page_alloc.c:8173:27: error: comparison between two arrays [-Werror=array-compare] 8173 | if (start <= pos && pos < end && size > adj) \ | In C++20, the comparision between arrays should be warned. Link: https://lkml.kernel.org/r/20211125130928.32465-1-sxwjean@me.com Signed-off-by: Xiongwei Song <sxwjean@gmail.com> Reported-by: Arthur Marsh <arthur.marsh@internode.on.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-29mm/damon/core-test: fix wrong expectations for 'damon_split_regions_of()'SeongJae Park1-2/+2
Kunit test cases for 'damon_split_regions_of()' expects the number of regions after calling the function will be same to their request ('nr_sub'). However, the requested number is just an upper-limit, because the function randomly decides the size of each sub-region. This fixes the wrong expectation. Link: https://lkml.kernel.org/r/20211028090628.14948-1-sj@kernel.org Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests") Signed-off-by: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-29mm: khugepaged: skip huge page collapse for special filesYang Shi1-8/+11
The read-only THP for filesystems will collapse THP for files opened readonly and mapped with VM_EXEC. The intended usecase is to avoid TLB misses for large text segments. But it doesn't restrict the file types so a THP could be collapsed for a non-regular file, for example, block device, if it is opened readonly and mapped with EXEC permission. This may cause bugs, like [1] and [2]. This is definitely not the intended usecase, so just collapse THP for regular files in order to close the attack surface. [shy828301@gmail.com: fix vm_file check [3]] Link: https://lore.kernel.org/lkml/CACkBjsYwLYLRmX8GpsDpMthagWOjWWrNxqY6ZLNQVr6yx+f5vA@mail.gmail.com/ [1] Link: https://lore.kernel.org/linux-mm/000000000000c6a82505ce284e4c@google.com/ [2] Link: https://lkml.kernel.org/r/CAHbLzkqTW9U3VvTu1Ki5v_cLRC9gHW+znBukg_ycergE0JWj-A@mail.gmail.com [3] Link: https://lkml.kernel.org/r/20211027195221.3825-1-shy828301@gmail.com Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS") Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Yang Shi <shy828301@gmail.com> Reported-by: Hao Sun <sunhao.th@gmail.com> Reported-by: syzbot+aae069be1de40fb11825@syzkaller.appspotmail.com Cc: Matthew Wilcox <willy@infradead.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Song Liu <songliubraving@fb.com> Cc: Andrea Righi <andrea.righi@canonical.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-29mm, thp: bail out early in collapse_file for writeback pageRongwei Wang1-1/+6
Currently collapse_file does not explicitly check PG_writeback, instead, page_has_private and try_to_release_page are used to filter writeback pages. This does not work for xfs with blocksize equal to or larger than pagesize, because in such case xfs has no page->private. This makes collapse_file bail out early for writeback page. Otherwise, xfs end_page_writeback will panic as follows. page:fffffe00201bcc80 refcount:0 mapcount:0 mapping:ffff0003f88c86a8 index:0x0 pfn:0x84ef32 aops:xfs_address_space_operations [xfs] ino:30000b7 dentry name:"libtest.so" flags: 0x57fffe0000008027(locked|referenced|uptodate|active|writeback) raw: 57fffe0000008027 ffff80001b48bc28 ffff80001b48bc28 ffff0003f88c86a8 raw: 0000000000000000 0000000000000000 00000000ffffffff ffff0000c3e9a000 page dumped because: VM_BUG_ON_PAGE(((unsigned int) page_ref_count(page) + 127u <= 127u)) page->mem_cgroup:ffff0000c3e9a000 ------------[ cut here ]------------ kernel BUG at include/linux/mm.h:1212! Internal error: Oops - BUG: 0 [#1] SMP Modules linked in: BUG: Bad page state in process khugepaged pfn:84ef32 xfs(E) page:fffffe00201bcc80 refcount:0 mapcount:0 mapping:0 index:0x0 pfn:0x84ef32 libcrc32c(E) rfkill(E) aes_ce_blk(E) crypto_simd(E) ... CPU: 25 PID: 0 Comm: swapper/25 Kdump: loaded Tainted: ... pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--) Call trace: end_page_writeback+0x1c0/0x214 iomap_finish_page_writeback+0x13c/0x204 iomap_finish_ioend+0xe8/0x19c iomap_writepage_end_bio+0x38/0x50 bio_endio+0x168/0x1ec blk_update_request+0x278/0x3f0 blk_mq_end_request+0x34/0x15c virtblk_request_done+0x38/0x74 [virtio_blk] blk_done_softirq+0xc4/0x110 __do_softirq+0x128/0x38c __irq_exit_rcu+0x118/0x150 irq_exit+0x1c/0x30 __handle_domain_irq+0x8c/0xf0 gic_handle_irq+0x84/0x108 el1_irq+0xcc/0x180 arch_cpu_idle+0x18/0x40 default_idle_call+0x4c/0x1a0 cpuidle_idle_call+0x168/0x1e0 do_idle+0xb4/0x104 cpu_startup_entry+0x30/0x9c secondary_start_kernel+0x104/0x180 Code: d4210000 b0006161 910c8021 94013f4d (d4210000) ---[ end trace 4a88c6a074082f8c ]--- Kernel panic - not syncing: Oops - BUG: Fatal exception in interrupt Link: https://lkml.kernel.org/r/20211022023052.33114-1-rongwei.wang@linux.alibaba.com Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS") Signed-off-by: Rongwei Wang <rongwei.wang@linux.alibaba.com> Signed-off-by: Xu Yu <xuyu@linux.alibaba.com> Suggested-by: Yang Shi <shy828301@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Song Liu <song@kernel.org> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-29mm/vmalloc: fix numa spreading for large hash tablesChen Wandun1-6/+9
Eric Dumazet reported a strange numa spreading info in [1], and found commit 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings") introduced this issue [2]. Dig into the difference before and after this patch, page allocation has some difference: before: alloc_large_system_hash __vmalloc __vmalloc_node(..., NUMA_NO_NODE, ...) __vmalloc_node_range __vmalloc_area_node alloc_page /* because NUMA_NO_NODE, so choose alloc_page branch */ alloc_pages_current alloc_page_interleave /* can be proved by print policy mode */ after: alloc_large_system_hash __vmalloc __vmalloc_node(..., NUMA_NO_NODE, ...) __vmalloc_node_range __vmalloc_area_node alloc_pages_node /* choose nid by nuam_mem_id() */ __alloc_pages_node(nid, ....) So after commit 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings"), it will allocate memory in current node instead of interleaving allocate memory. Link: https://lore.kernel.org/linux-mm/CANn89iL6AAyWhfxdHO+jaT075iOa3XcYn9k6JJc7JR2XYn6k_Q@mail.gmail.com/ [1] Link: https://lore.kernel.org/linux-mm/CANn89iLofTR=AK-QOZY87RdUZENCZUT4O6a0hvhu3_EwRMerOg@mail.gmail.com/ [2] Link: https://lkml.kernel.org/r/20211021080744.874701-2-chenwandun@huawei.com Fixes: 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings") Signed-off-by: Chen Wandun <chenwandun@huawei.com> Reported-by: Eric Dumazet <edumazet@google.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-29mm/secretmem: avoid letting secretmem_users drop to zeroKees Cook1-1/+1
Quoting Dmitry: "refcount_inc() needs to be done before fd_install(). After fd_install() finishes, the fd can be used by userspace and we can have secret data in memory before the refcount_inc(). A straightforward misuse where a user will predict the returned fd in another thread before the syscall returns and will use it to store secret data is somewhat dubious because such a user just shoots themself in the foot. But a more interesting misuse would be to close the predicted fd and decrement the refcount before the corresponding refcount_inc, this way one can briefly drop the refcount to zero while there are other users of secretmem." Move fd_install() after refcount_inc(). Link: https://lkml.kernel.org/r/20211021154046.880251-1-keescook@chromium.org Link: https://lore.kernel.org/lkml/CACT4Y+b1sW6-Hkn8HQYw_SsT7X3tp-CJNh2ci0wG3ZnQz9jjig@mail.gmail.com Fixes: 9a436f8ff631 ("PM: hibernate: disable when there are active secretmem users") Signed-off-by: Kees Cook <keescook@chromium.org> Reported-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Jordy Zomer <jordy@pwning.systems> Cc: Mike Rapoport <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-29mm/oom_kill.c: prevent a race between process_mrelease and exit_mmapSuren Baghdasaryan1-11/+12
Race between process_mrelease and exit_mmap, where free_pgtables is called while __oom_reap_task_mm is in progress, leads to kernel crash during pte_offset_map_lock call. oom-reaper avoids this race by setting MMF_OOM_VICTIM flag and causing exit_mmap to take and release mmap_write_lock, blocking it until oom-reaper releases mmap_read_lock. Reusing MMF_OOM_VICTIM for process_mrelease would be the simplest way to fix this race, however that would be considered a hack. Fix this race by elevating mm->mm_users and preventing exit_mmap from executing until process_mrelease is finished. Patch slightly refactors the code to adapt for a possible mmget_not_zero failure. This fix has considerable negative impact on process_mrelease performance and will likely need later optimization. Link: https://lkml.kernel.org/r/20211022014658.263508-1-surenb@google.com Fixes: 884a7e5964e0 ("mm: introduce process_mrelease system call") Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Roman Gushchin <guro@fb.com> Cc: Rik van Riel <riel@surriel.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Christian Brauner <christian@brauner.io> Cc: Christoph Hellwig <hch@infradead.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Florian Weimer <fweimer@redhat.com> Cc: Jan Engelhardt <jengelh@inai.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-29mm: filemap: check if THP has hwpoisoned subpage for PMD page faultYang Shi4-1/+28
When handling shmem page fault the THP with corrupted subpage could be PMD mapped if certain conditions are satisfied. But kernel is supposed to send SIGBUS when trying to map hwpoisoned page. There are two paths which may do PMD map: fault around and regular fault. Before commit f9ce0be71d1f ("mm: Cleanup faultaround and finish_fault() codepaths") the thing was even worse in fault around path. The THP could be PMD mapped as long as the VMA fits regardless what subpage is accessed and corrupted. After this commit as long as head page is not corrupted the THP could be PMD mapped. In the regular fault path the THP could be PMD mapped as long as the corrupted page is not accessed and the VMA fits. This loophole could be fixed by iterating every subpage to check if any of them is hwpoisoned or not, but it is somewhat costly in page fault path. So introduce a new page flag called HasHWPoisoned on the first tail page. It indicates the THP has hwpoisoned subpage(s). It is set if any subpage of THP is found hwpoisoned by memory failure and after the refcount is bumped successfully, then cleared when the THP is freed or split. The soft offline path doesn't need this since soft offline handler just marks a subpage hwpoisoned when the subpage is migrated successfully. But shmem THP didn't get split then migrated at all. Link: https://lkml.kernel.org/r/20211020210755.23964-3-shy828301@gmail.com Fixes: 800d8c63b2e9 ("shmem: add huge pages support") Signed-off-by: Yang Shi <shy828301@gmail.com> Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-29mm: hwpoison: remove the unnecessary THP checkYang Shi1-14/+0
When handling THP hwpoison checked if the THP is in allocation or free stage since hwpoison may mistreat it as hugetlb page. After commit 415c64c1453a ("mm/memory-failure: split thp earlier in memory error handling") the problem has been fixed, so this check is no longer needed. Remove it. The side effect of the removal is hwpoison may report unsplit THP instead of unknown error for shmem THP. It seems not like a big deal. The following patch "mm: filemap: check if THP has hwpoisoned subpage for PMD page fault" depends on this, which fixes shmem THP with hwpoisoned subpage(s) are mapped PMD wrongly. So this patch needs to be backported to -stable as well. Link: https://lkml.kernel.org/r/20211020210755.23964-2-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Suggested-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-29memcg: page_alloc: skip bulk allocator for __GFP_ACCOUNTShakeel Butt1-0/+4
Commit 5c1f4e690eec ("mm/vmalloc: switch to bulk allocator in __vmalloc_area_node()") switched to bulk page allocator for order 0 allocation backing vmalloc. However bulk page allocator does not support __GFP_ACCOUNT allocations and there are several users of kvmalloc(__GFP_ACCOUNT). For now make __GFP_ACCOUNT allocations bypass bulk page allocator. In future if there is workload that can be significantly improved with the bulk page allocator with __GFP_ACCCOUNT support, we can revisit the decision. Link: https://lkml.kernel.org/r/20211014151607.2171970-1-shakeelb@google.com Fixes: 5c1f4e690eec ("mm/vmalloc: switch to bulk allocator in __vmalloc_area_node()") Signed-off-by: Shakeel Butt <shakeelb@google.com> Reported-by: Vasily Averin <vvs@virtuozzo.com> Tested-by: Vasily Averin <vvs@virtuozzo.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-25secretmem: Prevent secretmem_users from wrapping to zeroMatthew Wilcox (Oracle)1-0/+2
Commit 110860541f44 ("mm/secretmem: use refcount_t instead of atomic_t") attempted to fix the problem of secretmem_users wrapping to zero and allowing suspend once again. But it was reverted in commit 87066fdd2e30 ("Revert 'mm/secretmem: use refcount_t instead of atomic_t'") because of the problems it caused - a refcount_t was not semantically the right type to use. Instead prevent secretmem_users from wrapping to zero by forbidding new users if the number of users has wrapped from positive to negative. This stops a long way short of reaching the necessary 4 billion users where it wraps to zero again, so there's no need to be clever with special anti-wrap types or checking the return value from atomic_inc(). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Jordy Zomer <jordy@pwning.systems> Cc: Kees Cook <keescook@chromium.org>, Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-24Revert "mm/secretmem: use refcount_t instead of atomic_t"Linus Torvalds1-5/+4
This reverts commit 110860541f443f950c1274f217a1a3e298670a33. Converting the "secretmem_users" counter to a refcount is incorrect, because a refcount is special in zero and can't just be incremented (but a count of users is not, and "no users" is actually perfectly valid and not a sign of a free'd resource). Reported-by: syzbot+75639e6a0331cd61d3e2@syzkaller.appspotmail.com Cc: Jordy Zomer <jordy@pwning.systems> Cc: Kees Cook <keescook@chromium.org>, Cc: Jordy Zomer <jordy@jordyzomer.github.io> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-22memblock: exclude MEMBLOCK_NOMAP regions from kmemleakMike Rapoport1-0/+3
Vladimir Zapolskiy reports: Commit a7259df76702 ("memblock: make memblock_find_in_range method private") invokes a kernel panic while running kmemleak on OF platforms with nomaped regions: Unable to handle kernel paging request at virtual address fff000021e00000 [...] scan_block+0x64/0x170 scan_gray_list+0xe8/0x17c kmemleak_scan+0x270/0x514 kmemleak_write+0x34c/0x4ac The memory allocated from memblock is registered with kmemleak, but if it is marked MEMBLOCK_NOMAP it won't have linear map entries so an attempt to scan such areas will fault. Ideally, memblock_mark_nomap() would inform kmemleak to ignore MEMBLOCK_NOMAP memory, but it can be called before kmemleak interfaces operating on physical addresses can use __va() conversion. Make sure that functions that mark allocated memory as MEMBLOCK_NOMAP take care of informing kmemleak to ignore such memory. Link: https://lore.kernel.org/all/8ade5174-b143-d621-8c8e-dc6a1898c6fb@linaro.org Link: https://lore.kernel.org/all/c30ff0a2-d196-c50d-22f0-bd50696b1205@quicinc.com Fixes: a7259df76702 ("memblock: make memblock_find_in_range method private") Reported-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org> Tested-by: Qian Cai <quic_qiancai@quicinc.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-22Revert "memblock: exclude NOMAP regions from kmemleak"Mike Rapoport1-6/+1
Commit 6e44bd6d34d6 ("memblock: exclude NOMAP regions from kmemleak") breaks boot on EFI systems with kmemleak and VM_DEBUG enabled: efi: Processing EFI memory map: efi: 0x000090000000-0x000091ffffff [Conventional| | | | | | | | | | |WB|WT|WC|UC] efi: 0x000092000000-0x0000928fffff [Runtime Data|RUN| | | | | | | | | |WB|WT|WC|UC] ------------[ cut here ]------------ kernel BUG at mm/kmemleak.c:1140! Internal error: Oops - BUG: 0 [#1] SMP Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 5.15.0-rc6-next-20211019+ #104 pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : kmemleak_free_part_phys+0x64/0x8c lr : kmemleak_free_part_phys+0x38/0x8c sp : ffff800011eafbc0 x29: ffff800011eafbc0 x28: 1fffff7fffb41c0d x27: fffffbfffda0e068 x26: 0000000092000000 x25: 1ffff000023d5f94 x24: ffff800011ed84d0 x23: ffff800011ed84c0 x22: ffff800011ed83d8 x21: 0000000000900000 x20: ffff800011782000 x19: 0000000092000000 x18: ffff800011ee0730 x17: 0000000000000000 x16: 0000000000000000 x15: 1ffff0000233252c x14: ffff800019a905a0 x13: 0000000000000001 x12: ffff7000023d5ed7 x11: 1ffff000023d5ed6 x10: ffff7000023d5ed6 x9 : dfff800000000000 x8 : ffff800011eaf6b7 x7 : 0000000000000001 x6 : ffff800011eaf6b0 x5 : 00008ffffdc2a12a x4 : ffff7000023d5ed7 x3 : 1ffff000023dbf99 x2 : 1ffff000022f0463 x1 : 0000000000000000 x0 : ffffffffffffffff Call trace: kmemleak_free_part_phys+0x64/0x8c memblock_mark_nomap+0x5c/0x78 reserve_regions+0x294/0x33c efi_init+0x2d0/0x490 setup_arch+0x80/0x138 start_kernel+0xa0/0x3ec __primary_switched+0xc0/0xc8 Code: 34000041 97d526e7 f9418e80 36000040 (d4210000) random: get_random_bytes called from print_oops_end_marker+0x34/0x80 with crng_init=0 ---[ end trace 0000000000000000 ]--- The crash happens because kmemleak_free_part_phys() tries to use __va() before memstart_addr is initialized and this triggers a VM_BUG_ON() in arch/arm64/include/asm/memory.h: Revert 6e44bd6d34d6 ("memblock: exclude NOMAP regions from kmemleak"), the issue it is fixing will be fixed differently. Reported-by: Qian Cai <quic_qiancai@quicinc.com> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-19mm/thp: decrease nr_thps in file's mapping on THP splitMarek Szyprowski1-2/+4
Decrease nr_thps counter in file's mapping to ensure that the page cache won't be dropped excessively on file write access if page has been already split. I've tried a test scenario running a big binary, kernel remaps it with THPs, then force a THP split with /sys/kernel/debug/split_huge_pages. During any further open of that binary with O_RDWR or O_WRITEONLY kernel drops page cache for it, because of non-zero thps counter. Link: https://lkml.kernel.org/r/20211012120237.2600-1-m.szyprowski@samsung.com Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Fixes: 09d91cda0e82 ("mm,thp: avoid writes to file with THP in pagecache") Fixes: 06d3eff62d9d ("mm/thp: fix node page state in split_huge_page_to_list()") Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Yang Shi <shy828301@gmail.com> Cc: <sfoon.kim@samsung.com> Cc: Song Liu <songliubraving@fb.com> Cc: Rik van Riel <riel@surriel.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Hillf Danton <hdanton@sina.com> Cc: Hugh Dickins <hughd@google.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-19mm, slub: fix incorrect memcg slab count for bulk freeMiaohe Lin1-1/+3
kmem_cache_free_bulk() will call memcg_slab_free_hook() for all objects when doing bulk free. So we shouldn't call memcg_slab_free_hook() again for bulk free to avoid incorrect memcg slab count. Link: https://lkml.kernel.org/r/20210916123920.48704-6-linmiaohe@huawei.com Fixes: d1b2cf6cb84a ("mm: memcg/slab: uncharge during kmem_cache_free_bulk()") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Bharata B Rao <bharata@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Faiyaz Mohammed <faiyazm@codeaurora.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-19mm, slub: fix potential use-after-free in slab_debugfs_fopsMiaohe Lin1-2/+4
When sysfs_slab_add failed, we shouldn't call debugfs_slab_add() for s because s will be freed soon. And slab_debugfs_fops will use s later leading to a use-after-free. Link: https://lkml.kernel.org/r/20210916123920.48704-5-linmiaohe@huawei.com Fixes: 64dd68497be7 ("mm: slub: move sysfs slab alloc/free interfaces to debugfs") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Bharata B Rao <bharata@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Faiyaz Mohammed <faiyazm@codeaurora.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-19mm, slub: fix potential memoryleak in kmem_cache_open()Miaohe Lin1-1/+1
In error path, the random_seq of slub cache might be leaked. Fix this by using __kmem_cache_release() to release all the relevant resources. Link: https://lkml.kernel.org/r/20210916123920.48704-4-linmiaohe@huawei.com Fixes: 210e7a43fa90 ("mm: SLUB freelist randomization") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Bharata B Rao <bharata@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Faiyaz Mohammed <faiyazm@codeaurora.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-19mm, slub: fix mismatch between reconstructed freelist depth and cntMiaohe Lin1-2/+9
If object's reuse is delayed, it will be excluded from the reconstructed freelist. But we forgot to adjust the cnt accordingly. So there will be a mismatch between reconstructed freelist depth and cnt. This will lead to free_debug_processing() complaining about freelist count or a incorrect slub inuse count. Link: https://lkml.kernel.org/r/20210916123920.48704-3-linmiaohe@huawei.com Fixes: c3895391df38 ("kasan, slub: fix handling of kasan_slab_free hook") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Bharata B Rao <bharata@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Faiyaz Mohammed <faiyazm@codeaurora.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-19mm, slub: fix two bugs in slab_debug_trace_open()Miaohe Lin1-1/+7
Patch series "Fixups for slub". This series contains various bug fixes for slub. We fix memoryleak, use-afer-free, NULL pointer dereferencing and so on in slub. More details can be found in the respective changelogs. This patch (of 5): It's possible that __seq_open_private() will return NULL. So we should check it before using lest dereferencing NULL pointer. And in error paths, we forgot to release private buffer via seq_release_private(). Memory will leak in these paths. Link: https://lkml.kernel.org/r/20210916123920.48704-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20210916123920.48704-2-linmiaohe@huawei.com Fixes: 64dd68497be7 ("mm: slub: move sysfs slab alloc/free interfaces to debugfs") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Faiyaz Mohammed <faiyazm@codeaurora.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Bharata B Rao <bharata@linux.ibm.com> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-19mm/mempolicy: do not allow illegal MPOL_F_NUMA_BALANCING | MPOL_LOCAL in mbind()Eric Dumazet1-11/+5
syzbot reported access to unitialized memory in mbind() [1] Issue came with commit bda420b98505 ("numa balancing: migrate on fault among multiple bound nodes") This commit added a new bit in MPOL_MODE_FLAGS, but only checked valid combination (MPOL_F_NUMA_BALANCING can only be used with MPOL_BIND) in do_set_mempolicy() This patch moves the check in sanitize_mpol_flags() so that it is also used by mbind() [1] BUG: KMSAN: uninit-value in __mpol_equal+0x567/0x590 mm/mempolicy.c:2260 __mpol_equal+0x567/0x590 mm/mempolicy.c:2260 mpol_equal include/linux/mempolicy.h:105 [inline] vma_merge+0x4a1/0x1e60 mm/mmap.c:1190 mbind_range+0xcc8/0x1e80 mm/mempolicy.c:811 do_mbind+0xf42/0x15f0 mm/mempolicy.c:1333 kernel_mbind mm/mempolicy.c:1483 [inline] __do_sys_mbind mm/mempolicy.c:1490 [inline] __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486 __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x44/0xae Uninit was created at: slab_alloc_node mm/slub.c:3221 [inline] slab_alloc mm/slub.c:3230 [inline] kmem_cache_alloc+0x751/0xff0 mm/slub.c:3235 mpol_new mm/mempolicy.c:293 [inline] do_mbind+0x912/0x15f0 mm/mempolicy.c:1289 kernel_mbind mm/mempolicy.c:1483 [inline] __do_sys_mbind mm/mempolicy.c:1490 [inline] __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486 __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x44/0xae ===================================================== Kernel panic - not syncing: panic_on_kmsan set ... CPU: 0 PID: 15049 Comm: syz-executor.0 Tainted: G B 5.15.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1ff/0x28e lib/dump_stack.c:106 dump_stack+0x25/0x28 lib/dump_stack.c:113 panic+0x44f/0xdeb kernel/panic.c:232 kmsan_report+0x2ee/0x300 mm/kmsan/report.c:186 __msan_warning+0xd7/0x150 mm/kmsan/instrumentation.c:208 __mpol_equal+0x567/0x590 mm/mempolicy.c:2260 mpol_equal include/linux/mempolicy.h:105 [inline] vma_merge+0x4a1/0x1e60 mm/mmap.c:1190 mbind_range+0xcc8/0x1e80 mm/mempolicy.c:811 do_mbind+0xf42/0x15f0 mm/mempolicy.c:1333 kernel_mbind mm/mempolicy.c:1483 [inline] __do_sys_mbind mm/mempolicy.c:1490 [inline] __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486 __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x44/0xae Link: https://lkml.kernel.org/r/20211001215630.810592-1-eric.dumazet@gmail.com Fixes: bda420b98505 ("numa balancing: migrate on fault among multiple bound nodes") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-19memblock: check memory total_sizePeng Fan1-1/+1
mem=[X][G|M] is broken on ARM64 platform, there are cases that even type.cnt is 1, but total_size is not 0 because regions are merged into 1. So only check 'cnt' is not enough, total_size should be used, othersize bootargs 'mem=[X][G|B]' not work anymore. Link: https://lkml.kernel.org/r/20210930024437.32598-1-peng.fan@oss.nxp.com Fixes: e888fa7bb882 ("memblock: Check memory add/cap ordering") Signed-off-by: Peng Fan <peng.fan@nxp.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Geert Uytterhoeven <geert+renesas@glider.be> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-19mm/migrate: fix CPUHP state to update node demotion orderHuang Ying1-3/+5
The node demotion order needs to be updated during CPU hotplug. Because whether a NUMA node has CPU may influence the demotion order. The update function should be called during CPU online/offline after the node_states[N_CPU] has been updated. That is done in CPUHP_AP_ONLINE_DYN during CPU online and in CPUHP_MM_VMSTAT_DEAD during CPU offline. But in commit 884a6e5d1f93 ("mm/migrate: update node demotion order on hotplug events"), the function to update node demotion order is called in CPUHP_AP_ONLINE_DYN during CPU online/offline. This doesn't satisfy the order requirement. For example, there are 4 CPUs (P0, P1, P2, P3) in 2 sockets (P0, P1 in S0 and P2, P3 in S1), the demotion order is - S0 -> NUMA_NO_NODE - S1 -> NUMA_NO_NODE After P2 and P3 is offlined, because S1 has no CPU now, the demotion order should have been changed to - S0 -> S1 - S1 -> NO_NODE but it isn't changed, because the order updating callback for CPU hotplug doesn't see the new nodemask. After that, if P1 is offlined, the demotion order is changed to the expected order as above. So in this patch, we added CPUHP_AP_MM_DEMOTION_ONLINE and CPUHP_MM_DEMOTION_DEAD to be called after CPUHP_AP_ONLINE_DYN and CPUHP_MM_VMSTAT_DEAD during CPU online and offline, and register the update function on them. Link: https://lkml.kernel.org/r/20210929060351.7293-1-ying.huang@intel.com Fixes: 884a6e5d1f93 ("mm/migrate: update node demotion order on hotplug events") Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Wei Xu <weixugc@google.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: Keith Busch <kbusch@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-19mm/migrate: add CPU hotplug to demotion #ifdefDave Hansen3-26/+24
Once upon a time, the node demotion updates were driven solely by memory hotplug events. But now, there are handlers for both CPU and memory hotplug. However, the #ifdef around the code checks only memory hotplug. A system that has HOTPLUG_CPU=y but MEMORY_HOTPLUG=n would miss CPU hotplug events. Update the #ifdef around the common code. Add memory and CPU-specific #ifdefs for their handlers. These memory/CPU #ifdefs avoid unused function warnings when their Kconfig option is off. [arnd@arndb.de: rework hotplug_memory_notifier() stub] Link: https://lkml.kernel.org/r/20211013144029.2154629-1-arnd@kernel.org Link: https://lkml.kernel.org/r/20210924161255.E5FE8F7E@davehans-spike.ostc.intel.com Fixes: 884a6e5d1f93 ("mm/migrate: update node demotion order on hotplug events") Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Wei Xu <weixugc@google.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-19mm/migrate: optimize hotplug-time demotion order updatesDave Hansen1-1/+11
Patch series "mm/migrate: 5.15 fixes for automatic demotion", v2. This contains two fixes for the "automatic demotion" code which was merged into 5.15: * Fix memory hotplug performance regression by watching suppressing any real action on irrelevant hotplug events. * Ensure CPU hotplug handler is registered when memory hotplug is disabled. This patch (of 2): == tl;dr == Automatic demotion opted for a simple, lazy approach to handling hotplug events. This noticeably slows down memory hotplug[1]. Optimize away updates to the demotion order when memory hotplug events should have no effect. This has no effect on CPU hotplug. There is no known problem on the CPU side and any work there will be in a separate series. == Background == Automatic demotion is a memory migration strategy to ensure that new allocations have room in faster memory tiers on tiered memory systems. The kernel maintains an array (node_demotion[]) to drive these migrations. The node_demotion[] path is calculated by starting at nodes with CPUs and then "walking" to nodes with memory. Only hotplug events which online or offline a node with memory (N_ONLINE) or CPUs (N_CPU) will actually affect the migration order. == Problem == However, the current code is lazy. It completely regenerates the migration order on *any* CPU or memory hotplug event. The logic was that these events are extremely rare and that the overhead from indiscriminate order regeneration is minimal. Part of the update logic involves a synchronize_rcu(), which is a pretty big hammer. Its overhead was large enough to be detected by some 0day tests that watch memory hotplug performance[1]. == Solution == Add a new helper (node_demotion_topo_changed()) which can differentiate between superfluous and impactful hotplug events. Skip the expensive update operation for superfluous events. == Aside: Locking == It took me a few moments to declare the locking to be safe enough for node_demotion_topo_changed() to work. It all hinges on the memory hotplug lock: During memory hotplug events, 'mem_hotplug_lock' is held for write. This ensures that two memory hotplug events can not be called simultaneously. CPU hotplug has a similar lock (cpuhp_state_mutex) which also provides mutual exclusion between CPU hotplug events. In addition, the demotion code acquire and hold the mem_hotplug_lock for read during its CPU hotplug handlers. This provides mutual exclusion between the demotion memory hotplug callbacks and the CPU hotplug callbacks. This effectively allows treating the migration target generation code to act as if it is single-threaded. 1. https://lore.kernel.org/all/20210905135932.GE15026@xsang-OptiPlex-9020/ Link: https://lkml.kernel.org/r/20210924161251.093CCD06@davehans-spike.ostc.intel.com Link: https://lkml.kernel.org/r/20210924161253.D7673E31@davehans-spike.ostc.intel.com Fixes: 884a6e5d1f93 ("mm/migrate: update node demotion order on hotplug events") Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reported-by: kernel test robot <oliver.sang@intel.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Wei Xu <weixugc@google.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Thelen <gthelen@google.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-13memblock: exclude NOMAP regions from kmemleakMike Rapoport1-1/+6
Vladimir Zapolskiy reports: commit a7259df76702 ("memblock: make memblock_find_in_range method private") invokes a kernel panic while running kmemleak on OF platforms with nomaped regions: Unable to handle kernel paging request at virtual address fff000021e00000 [...] scan_block+0x64/0x170 scan_gray_list+0xe8/0x17c kmemleak_scan+0x270/0x514 kmemleak_write+0x34c/0x4ac Indeed, NOMAP regions don't have linear map entries so an attempt to scan these areas would fault. Prevent such faults by excluding NOMAP regions from kmemleak. Link: https://lore.kernel.org/all/8ade5174-b143-d621-8c8e-dc6a1898c6fb@linaro.org Fixes: a7259df76702 ("memblock: make memblock_find_in_range method private") Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Tested-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
2021-09-25mm: fix uninitialized use in overcommit_policy_handlerChen Jun1-2/+2
We get an unexpected value of /proc/sys/vm/overcommit_memory after running the following program: int main() { int fd = open("/proc/sys/vm/overcommit_memory", O_RDWR); write(fd, "1", 1); write(fd, "2", 1); close(fd); } write(fd, "2", 1) will pass *ppos = 1 to proc_dointvec_minmax. proc_dointvec_minmax will return 0 without setting new_policy. t.data = &new_policy; ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos) -->do_proc_dointvec -->__do_proc_dointvec if (write) { if (proc_first_pos_non_zero_ignore(ppos, table)) goto out; sysctl_overcommit_memory = new_policy; so sysctl_overcommit_memory will be set to an uninitialized value. Check whether new_policy has been changed by proc_dointvec_minmax. Link: https://lkml.kernel.org/r/20210923020524.13289-1-chenjun102@huawei.com Fixes: 56f3547bfa4d ("mm: adjust vm_committed_as_batch according to vm overcommit policy") Signed-off-by: Chen Jun <chenjun102@huawei.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Feng Tang <feng.tang@intel.com> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Rui Xiang <rui.xiang@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-25mm/memory_failure: fix the missing pte_unmap() callQi Zheng1-5/+5
The paired pte_unmap() call is missing before the dev_pagemap_mapping_shift() returns. So fix it. David says: "I guess this code never runs on 32bit / highmem, that's why we didn't notice so far". [akpm@linux-foundation.org: cleanup] Link: https://lkml.kernel.org/r/20210923122642.4999-1-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-25mm/debug: sync up latest migrate_reason to migrate_reason_namesWeizhao Ouyang1-0/+1
Sync up MR_DEMOTION to migrate_reason_names and add a synch prompt. Link: https://lkml.kernel.org/r/20210921064553.293905-3-o451686892@gmail.com Fixes: 26aa2d199d6f ("mm/migrate: demote pages during reclaim") Signed-off-by: Weizhao Ouyang <o451686892@gmail.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Mina Almasry <almasrymina@google.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wei Xu <weixugc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-25mm/debug: sync up MR_CONTIG_RANGE and MR_LONGTERM_PINWeizhao Ouyang1-1/+2
Sync up MR_CONTIG_RANGE and MR_LONGTERM_PIN to migrate_reason_names. Link: https://lkml.kernel.org/r/20210921064553.293905-2-o451686892@gmail.com Fixes: 310253514bbf ("mm/migrate: rename migration reason MR_CMA to MR_CONTIG_RANGE") Fixes: d1e153fea2a8 ("mm/gup: migrate pinned pages out of movable zone") Signed-off-by: Weizhao Ouyang <o451686892@gmail.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Mina Almasry <almasrymina@google.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wei Xu <weixugc@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-25mm: fs: invalidate bh_lrus for only cold pathMinchan Kim1-3/+16
The kernel test robot reported the regression of fio.write_iops[1] with commit 8cc621d2f45d ("mm: fs: invalidate BH LRU during page migration"). Since lru_add_drain is called frequently, invalidate bh_lrus there could increase bh_lrus cache miss ratio, which needs more IO in the end. This patch moves the bh_lrus invalidation from the hot path( e.g., zap_page_range, pagevec_release) to cold path(i.e., lru_add_drain_all, lru_cache_disable). Zhengjun Xing confirmed "I test the patch, the regression reduced to -2.9%" [1] https://lore.kernel.org/lkml/20210520083144.GD14190@xsang-OptiPlex-9020/ [2] 8cc621d2f45d, mm: fs: invalidate BH LRU during page migration Link: https://lkml.kernel.org/r/20210907212347.1977686-1-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: kernel test robot <oliver.sang@intel.com> Reviewed-by: Chris Goldsworthy <cgoldswo@codeaurora.org> Tested-by: "Xing, Zhengjun" <zhengjun.xing@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-25mm/shmem.c: fix judgment error in shmem_is_huge()Liu Yuntao1-2/+2
In the case of SHMEM_HUGE_WITHIN_SIZE, the page index is not rounded up correctly. When the page index points to the first page in a huge page, round_up() cannot bring it to the end of the huge page, but to the end of the previous one. An example: HPAGE_PMD_NR on my machine is 512(2 MB huge page size). After allcoating a 3000 KB buffer, I access it at location 2050 KB. In shmem_is_huge(), the corresponding index happens to be 512. After rounded up by HPAGE_PMD_NR, it will still be 512 which is smaller than i_size, and shmem_is_huge() will return true. As a result, my buffer takes an additional huge page, and that shouldn't happen when shmem_enabled is set to within_size. Link: https://lkml.kernel.org/r/20210909032007.18353-1-liuyuntao10@huawei.com Fixes: f3f0e1d2150b2b ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by: Liu Yuntao <liuyuntao10@huawei.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: wuxu.wu <wuxu.wu@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-25mm/damon: don't use strnlen() with known-bogus source lengthAdam Borowski1-8/+8
gcc knows the true length too, and rightfully complains. Link: https://lkml.kernel.org/r/20210912204447.10427-1-kilobyte@angband.pl Signed-off-by: Adam Borowski <kilobyte@angband.pl> Cc: SeongJae Park <sj38.park@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-25mm, hwpoison: add is_free_buddy_page() in HWPoisonHandlable()Naoya Horiguchi1-1/+1
Commit fcc00621d88b ("mm/hwpoison: retry with shake_page() for unhandlable pages") changed the return value of __get_hwpoison_page() to retry for transiently unhandlable cases. However, __get_hwpoison_page() currently fails to properly judge buddy pages as handlable, so hard/soft offline for buddy pages always fail as "unhandlable page". This is totally regrettable. So let's add is_free_buddy_page() in HWPoisonHandlable(), so that __get_hwpoison_page() returns different return values between buddy pages and unhandlable pages as intended. Link: https://lkml.kernel.org/r/20210909004131.163221-1-naoya.horiguchi@linux.dev Fixes: fcc00621d88b ("mm/hwpoison: retry with shake_page() for unhandlable pages") Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-23memcg: flush lruvec stats in the refaultShakeel Butt2-10/+1
Prior to the commit 7e1c0d6f5820 ("memcg: switch lruvec stats to rstat") and the commit aa48e47e3906 ("memcg: infrastructure to flush memcg stats"), each lruvec memcg stats can be off by (nr_cgroups * nr_cpus * 32) at worst and for unbounded amount of time. The commit aa48e47e3906 moved the lruvec stats to rstat infrastructure and the commit 7e1c0d6f5820 bounded the error for all the lruvec stats to (nr_cpus * 32) at worst for at most 2 seconds. More specifically it decoupled the number of stats and the number of cgroups from the error rate. However this reduction in error comes with the cost of triggering the slowpath of stats update more frequently. Previously in the slowpath the kernel adds the stats up the memcg tree. After aa48e47e3906, the kernel triggers the asyn lruvec stats flush through queue_work(). This causes regression reports from 0day kernel bot [1] as well as from phoronix test suite [2]. We tried two options to fix the regression: 1) Increase the threshold to trigger the slowpath in lruvec stats update codepath from 32 to 512. 2) Remove the slowpath from lruvec stats update codepath and instead flush the stats in the page refault codepath. The assumption is that the kernel timely flush the stats, so, the update tree would be small in the refault codepath to not cause the preformance impact. Following are the results of will-it-scale/page_fault[1|2|3] benchmark on four settings i.e. (1) 5.15-rc1 as baseline (2) 5.15-rc1 with aa48e47e3906 and 7e1c0d6f5820 reverted (3) 5.15-rc1 with option-1 (4) 5.15-rc1 with option-2. test (1) (2) (3) (4) pg_f1 368563 406277 (10.23%) 399693 (8.44%) 416398 (12.97%) pg_f2 338399 372133 (9.96%) 369180 (9.09%) 381024 (12.59%) pg_f3 500853 575399 (14.88%) 570388 (13.88%) 576083 (15.02%) From the above result, it seems like the option-2 not only solves the regression but also improves the performance for at least these benchmarks. Feng Tang (intel) ran the aim7 benchmark with these two options and confirms that option-1 reduces the regression but option-2 removes the regression. Michael Larabel (phoronix) ran multiple benchmarks with these options and reported the results at [3] and it shows for most benchmarks option-2 removes the regression introduced by the commit aa48e47e3906 ("memcg: infrastructure to flush memcg stats"). Based on the experiment results, this patch proposed the option-2 as the solution to resolve the regression. Link: https://lore.kernel.org/all/20210726022421.GB21872@xsang-OptiPlex-9020 [1] Link: https://www.phoronix.com/scan.php?page=article&item=linux515-compile-regress [2] Link: https://openbenchmarking.org/result/2109226-DEBU-LINUX5104 [3] Fixes: aa48e47e3906 ("memcg: infrastructure to flush memcg stats") Signed-off-by: Shakeel Butt <shakeelb@google.com> Tested-by: Michael Larabel <Michael@phoronix.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Roman Gushchin <guro@fb.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Hillf Danton <hdanton@sina.com>, Cc: Michal Koutný <mkoutny@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org>, Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-21Merge tag 'afs-fixes-20210913' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull AFS fixes from David Howells: "Fixes for AFS problems that can cause data corruption due to interaction with another client modifying data cached locally: - When d_revalidating a dentry, don't look at the inode to which it points. Only check the directory to which the dentry belongs. This was confusing things and causing the silly-rename cleanup code to remove the file now at the dentry of a file that got deleted. - Fix mmap data coherency. When a callback break is received that relates to a file that we have cached, the data content may have been changed (there are other reasons, such as the user's rights having been changed). However, we're checking it lazily, only on entry to the kernel, which doesn't happen if we have a writeable shared mapped page on that file. We make the kernel keep track of mmapped files and clear all PTEs mapping to that file as soon as the callback comes in by calling unmap_mapping_pages() (we don't necessarily want to zap the pagecache). This causes the kernel to be reentered when userspace tries to access the mmapped address range again - and at that point we can query the server and, if we need to, zap the page cache. Ideally, I would check each file at the point of notification, but that involves poking the server[*] - which is holding an exclusive lock on the vnode it is changing, waiting for all the clients it notified to reply. This could then deadlock against the server. Further, invalidating the pagecache might call ->launder_page(), which would try to write to the file, which would definitely deadlock. (AFS doesn't lease file access). [*] Checking to see if the file content has changed is a matter of comparing the current data version number, but we have to ask the server for that. We also need to get a new callback promise and we need to poke the server for that too. - Add some more points at which the inode is validated, since we're doing it lazily, notably in ->read_iter() and ->page_mkwrite(), but also when performing some directory operations. Ideally, checking in ->read_iter() would be done in some derivation of filemap_read(). If we're going to call the server to read the file, then we get the file status fetch as part of that. - The above is now causing us to make a lot more calls to afs_validate() to check the inode - and afs_validate() takes the RCU read lock each time to make a quick check (ie. afs_check_validity()). This is entirely for the purpose of checking cb_s_break to see if the server we're using reinitialised its list of callbacks - however this isn't a very common event, so most of the time we're taking this needlessly. Add a new cell-wide counter to count the number of reinitialisations done by any server and check that - and only if that changes, take the RCU read lock and check the server list (the server list may change, but the cell a file is part of won't). - Don't update vnode->cb_s_break and ->cb_v_break inside the validity checking loop. The cb_lock is done with read_seqretry, so we might go round the loop a second time after resetting those values - and that could cause someone else checking validity to miss something (I think). Also included are patches for fixes for some bugs encountered whilst debugging this: - Fix a leak of afs_read objects and fix a leak of keys hidden by that. - Fix a leak of pages that couldn't be added to extend a writeback. - Fix the maintenance of i_blocks when i_size is changed by a local write or a local dir edit" Link: https://bugzilla.kernel.org/show_bug.cgi?id=214217 [1] Link: https://lore.kernel.org/r/163111665183.283156.17200205573146438918.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163113612442.352844.11162345591911691150.stgit@warthog.procyon.org.uk/ # i_blocks patch * tag 'afs-fixes-20210913' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: afs: Fix updating of i_blocks on file/dir extension afs: Fix corruption in reads at fpos 2G-4G from an OpenAFS server afs: Try to avoid taking RCU read lock when checking vnode validity afs: Fix mmap coherency vs 3rd-party changes afs: Fix incorrect triggering of sillyrename on 3rd-party invalidation afs: Add missing vnode validation checks afs: Fix page leak afs: Fix missing put on afs_read objects and missing get on the key therein
2021-09-14memblock: introduce saner 'memblock_free_ptr()' interfaceLinus Torvalds1-1/+15
The boot-time allocation interface for memblock is a mess, with 'memblock_alloc()' returning a virtual pointer, but then you are supposed to free it with 'memblock_free()' that takes a _physical_ address. Not only is that all kinds of strange and illogical, but it actually causes bugs, when people then use it like a normal allocation function, and it fails spectacularly on a NULL pointer: https://lore.kernel.org/all/20210912140820.GD25450@xsang-OptiPlex-9020/ or just random memory corruption if the debug checks don't catch it: https://lore.kernel.org/all/61ab2d0c-3313-aaab-514c-e15b7aa054a0@suse.cz/ I really don't want to apply patches that treat the symptoms, when the fundamental cause is this horribly confusing interface. I started out looking at just automating a sane replacement sequence, but because of this mix or virtual and physical addresses, and because people have used the "__pa()" macro that can take either a regular kernel pointer, or just the raw "unsigned long" address, it's all quite messy. So this just introduces a new saner interface for freeing a virtual address that was allocated using 'memblock_alloc()', and that was kept as a regular kernel pointer. And then it converts a couple of users that are obvious and easy to test, including the 'xbc_nodes' case in lib/bootconfig.c that caused problems. Reported-by: kernel test robot <oliver.sang@intel.com> Fixes: 40caa127f3c7 ("init: bootconfig: Remove all bootconfig data when the init memory is removed") Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-13Merge branch 'gcc-min-version-5.1' (make gcc-5.1 the minimum version)Linus Torvalds1-2/+0
Merge patch series from Nick Desaulniers to update the minimum gcc version to 5.1. This is some of the left-overs from the merge window that I didn't want to deal with yesterday, so it comes in after -rc1 but was sent before. Gcc-4.9 support has been an annoyance for some time, and with -Werror I had the choice of applying a fairly big patch from Kees Cook to remove a fair number of initializer warnings (still leaving some), or this patch series from Nick that just removes the source of the problem. The initializer cleanups might still be worth it regardless, but honestly, I preferred just tackling the problem with gcc-4.9 head-on. We've been more aggressiuve about no longer having to care about compilers that were released a long time ago, and I think it's been a good thing. I added a couple of patches on top to sort out a few left-overs now that we no longer support gcc-4.x. As noted by Arnd, as a result of this minimum compiler version upgrade we can probably change our use of '--std=gnu89' to '--std=gnu11', and finally start using local loop declarations etc. But this series does _not_ yet do that. Link: https://lore.kernel.org/all/20210909182525.372ee687@canb.auug.org.au/ Link: https://lore.kernel.org/lkml/CAK7LNASs6dvU6D3jL2GG3jW58fXfaj6VNOe55NJnTB8UPuk2pA@mail.gmail.com/ Link: https://github.com/ClangBuiltLinux/linux/issues/1438 * emailed patches from Nick Desaulniers <ndesaulniers@google.com>: Drop some straggling mentions of gcc-4.9 as being stale compiler_attributes.h: drop __has_attribute() support for gcc4 vmlinux.lds.h: remove old check for GCC 4.9 compiler-gcc.h: drop checks for older GCC versions Makefile: drop GCC < 5 -fno-var-tracking-assignments workaround arm64: remove GCC version check for ARCH_SUPPORTS_INT128 powerpc: remove GCC version check for UPD_CONSTR riscv: remove Kconfig check for GCC version for ARCH_RV64I Kconfig.debug: drop GCC 5+ version check for DWARF5 mm/ksm: remove old GCC 4.9+ check compiler.h: drop fallback overflow checkers Documentation: raise minimum supported version of GCC to 5.1
2021-09-13mm/ksm: remove old GCC 4.9+ checkNick Desaulniers1-2/+0
The minimum supported version of GCC has been raised to GCC 5.1. Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-13afs: Fix mmap coherency vs 3rd-party changesDavid Howells1-0/+1
Fix the coherency management of mmap'd data such that 3rd-party changes become visible as soon as possible after the callback notification is delivered by the fileserver. This is done by the following means: (1) When we break a callback on a vnode specified by the CB.CallBack call from the server, we queue a work item (vnode->cb_work) to go and clobber all the PTEs mapping to that inode. This causes the CPU to trip through the ->map_pages() and ->page_mkwrite() handlers if userspace attempts to access the page(s) again. (Ideally, this would be done in the service handler for CB.CallBack, but the server is waiting for our reply before considering, and we have a list of vnodes, all of which need breaking - and the process of getting the mmap_lock and stripping the PTEs on all CPUs could be quite slow.) (2) Call afs_validate() from the ->map_pages() handler to check to see if the file has changed and to get a new callback promise from the server. Also handle the fileserver telling us that it's dropping all callbacks, possibly after it's been restarted by sending us a CB.InitCallBackState* call by the following means: (3) Maintain a per-cell list of afs files that are currently mmap'd (cell->fs_open_mmaps). (4) Add a work item to each server that is invoked if there are any open mmaps when CB.InitCallBackState happens. This work item goes through the aforementioned list and invokes the vnode->cb_work work item for each one that is currently using this server. This causes the PTEs to be cleared, causing ->map_pages() or ->page_mkwrite() to be called again, thereby calling afs_validate() again. I've chosen to simply strip the PTEs at the point of notification reception rather than invalidate all the pages as well because (a) it's faster, (b) we may get a notification for other reasons than the data being altered (in which case we don't want to clobber the pagecache) and (c) we need to ask the server to find out - and I don't want to wait for the reply before holding up userspace. This was tested using the attached test program: #include <stdbool.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> #include <sys/mman.h> int main(int argc, char *argv[]) { size_t size = getpagesize(); unsigned char *p; bool mod = (argc == 3); int fd; if (argc != 2 && argc != 3) { fprintf(stderr, "Format: %s <file> [mod]\n", argv[0]); exit(2); } fd = open(argv[1], mod ? O_RDWR : O_RDONLY); if (fd < 0) { perror(argv[1]); exit(1); } p = mmap(NULL, size, mod ? PROT_READ|PROT_WRITE : PROT_READ, MAP_SHARED, fd, 0); if (p == MAP_FAILED) { perror("mmap"); exit(1); } for (;;) { if (mod) { p[0]++; msync(p, size, MS_ASYNC); fsync(fd); } printf("%02x", p[0]); fflush(stdout); sleep(1); } } It runs in two modes: in one mode, it mmaps a file, then sits in a loop reading the first byte, printing it and sleeping for a second; in the second mode it mmaps a file, then sits in a loop incrementing the first byte and flushing, then printing and sleeping. Two instances of this program can be run on different machines, one doing the reading and one doing the writing. The reader should see the changes made by the writer, but without this patch, they aren't because validity checking is being done lazily - only on entry to the filesystem. Testing the InitCallBackState change is more complicated. The server has to be taken offline, the saved callback state file removed and then the server restarted whilst the reading-mode program continues to run. The client machine then has to poke the server to trigger the InitCallBackState call. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Markus Suvanto <markus.suvanto@gmail.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/163111668833.283156.382633263709075739.stgit@warthog.procyon.org.uk/
2021-09-09Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds1-6/+22
Pull ARM development updates from Russell King: - Rename "mod_init" and "mod_exit" so that initcall debug output is actually useful (Randy Dunlap) - Update maintainers entries for linux-arm-kernel to indicate it is moderated for non-subscribers (Randy Dunlap) - Move install rules to arch/arm/Makefile (Masahiro Yamada) - Drop unnecessary ARCH_NR_GPIOS definition (Linus Walleij) - Don't warn about atags_to_fdt() stack size (David Heidelberg) - Speed up unaligned copy_{from,to}_kernel_nofault (Arnd Bergmann) - Get rid of set_fs() usage (Arnd Bergmann) - Remove checks for GCC prior to v4.6 (Geert Uytterhoeven) * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 9118/1: div64: Remove always-true __div64_const32_is_OK() duplicate ARM: 9117/1: asm-generic: div64: Remove always-true __div64_const32_is_OK() ARM: 9116/1: unified: Remove check for gcc < 4 ARM: 9110/1: oabi-compat: fix oabi epoll sparse warning ARM: 9113/1: uaccess: remove set_fs() implementation ARM: 9112/1: uaccess: add __{get,put}_kernel_nofault ARM: 9111/1: oabi-compat: rework fcntl64() emulation ARM: 9114/1: oabi-compat: rework sys_semtimedop emulation ARM: 9108/1: oabi-compat: rework epoll_wait/epoll_pwait emulation ARM: 9107/1: syscall: always store thread_info->abi_syscall ARM: 9109/1: oabi-compat: add epoll_pwait handler ARM: 9106/1: traps: use get_kernel_nofault instead of set_fs() ARM: 9115/1: mm/maccess: fix unaligned copy_{from,to}_kernel_nofault ARM: 9105/1: atags_to_fdt: don't warn about stack size ARM: 9103/1: Drop ARCH_NR_GPIOS definition ARM: 9102/1: move theinstall rules to arch/arm/Makefile ARM: 9100/1: MAINTAINERS: mark all linux-arm-kernel@infradead list as moderated ARM: 9099/1: crypto: rename 'mod_init' & 'mod_exit' functions to be module-specific
2021-09-09Merge branches 'akpm' and 'akpm-hotfixes' (patches from Andrew)Linus Torvalds7-187/+150
Merge yet more updates and hotfixes from Andrew Morton: "Post-linux-next material, based upon latest upstream to catch the now-merged dependencies: - 10 patches. Subsystems affected by this patch series: mm (vmstat and migration) and compat. And bunch of hotfixes, mostly cc:stable: - 8 patches. Subsystems affected by this patch series: mm (hmm, hugetlb, vmscan, pagealloc, pagemap, kmemleak, mempolicy, and memblock)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: arch: remove compat_alloc_user_space compat: remove some compat entry points mm: simplify compat numa syscalls mm: simplify compat_sys_move_pages kexec: avoid compat_alloc_user_space kexec: move locking into do_kexec_load mm: migrate: change to use bool type for 'page_was_mapped' mm: migrate: fix the incorrect function name in comments mm: migrate: introduce a local variable to get the number of pages mm/vmstat: protect per cpu variables with preempt disable on RT * emailed hotfixes from Andrew Morton <akpm@linux-foundation.org>: nds32/setup: remove unused memblock_region variable in setup_memory() mm/mempolicy: fix a race between offset_il_node and mpol_rebind_task mm/kmemleak: allow __GFP_NOLOCKDEP passed to kmemleak's gfp mmap_lock: change trace and locking order mm/page_alloc.c: avoid accessing uninitialized pcp page migratetype mm,vmscan: fix divide by zero in get_scan_count mm/hugetlb: initialize hugetlb_usage in mm_init mm/hmm: bypass devmap pte when all pfn requested flags are fulfilled
2021-09-09mm/mempolicy: fix a race between offset_il_node and mpol_rebind_taskyanghui1-4/+13
Servers happened below panic: Kernel version:5.4.56 BUG: unable to handle page fault for address: 0000000000002c48 RIP: 0010:__next_zones_zonelist+0x1d/0x40 Call Trace: __alloc_pages_nodemask+0x277/0x310 alloc_page_interleave+0x13/0x70 handle_mm_fault+0xf99/0x1390 __do_page_fault+0x288/0x500 do_page_fault+0x30/0x110 page_fault+0x3e/0x50 The reason for the panic is that MAX_NUMNODES is passed in the third parameter in __alloc_pages_nodemask(preferred_nid). So access to zonelist->zoneref->zone_idx in __next_zones_zonelist will cause a panic. In offset_il_node(), first_node() returns nid from pol->v.nodes, after this other threads may chang pol->v.nodes before next_node(). This race condition will let next_node return MAX_NUMNODES. So put pol->nodes in a local variable. The race condition is between offset_il_node and cpuset_change_task_nodemask: CPU0: CPU1: alloc_pages_vma() interleave_nid(pol,) offset_il_node(pol,) first_node(pol->v.nodes) cpuset_change_task_nodemask //nodes==0xc mpol_rebind_task mpol_rebind_policy mpol_rebind_nodemask(pol,nodes) //nodes==0x3 next_node(nid, pol->v.nodes)//return MAX_NUMNODES Link: https://lkml.kernel.org/r/20210906034658.48721-1-yanghui.def@bytedance.com Signed-off-by: yanghui <yanghui.def@bytedance.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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