kernel/linux.git/mm/util.c, branch v6.1.168

mm: unconditionally close VMAs on error

2024-11-22T14:37:34+00:00

[ Upstream commit 4080ef1579b2413435413988d14ac8c68e4d42c8 ] Incorrect invocation of VMA callbacks when the VMA is no longer in a consistent state is bug prone and risky to perform. With regards to the important vm_ops->close() callback We have gone to great lengths to try to track whether or not we ought to close VMAs. Rather than doing so and risking making a mistake somewhere, instead unconditionally close and reset vma->vm_ops to an empty dummy operations set with a NULL .close operator. We introduce a new function to do so - vma_close() - and simplify existing vms logic which tracked whether we needed to close or not. This simplifies the logic, avoids incorrect double-calling of the .close() callback and allows us to update error paths to simply call vma_close() unconditionally - making VMA closure idempotent. Link: https://lkml.kernel.org/r/28e89dda96f68c505cb6f8e9fc9b57c3e9f74b42.1730224667.git.lorenzo.stoakes@oracle.com Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes Reported-by: Jann Horn Reviewed-by: Vlastimil Babka Reviewed-by: Liam R. Howlett Reviewed-by: Jann Horn Cc: Andreas Larsson Cc: Catalin Marinas Cc: David S. Miller Cc: Helge Deller Cc: James E.J. Bottomley Cc: Linus Torvalds Cc: Mark Brown Cc: Peter Xu Cc: Will Deacon Cc: Signed-off-by: Andrew Morton Signed-off-by: Lorenzo Stoakes Signed-off-by: Greg Kroah-Hartman

mm: avoid unsafe VMA hook invocation when error arises on mmap hook

2024-11-22T14:37:34+00:00

[ Upstream commit 3dd6ed34ce1f2356a77fb88edafb5ec96784e3cf ] Patch series "fix error handling in mmap_region() and refactor (hotfixes)", v4. mmap_region() is somewhat terrifying, with spaghetti-like control flow and numerous means by which issues can arise and incomplete state, memory leaks and other unpleasantness can occur. A large amount of the complexity arises from trying to handle errors late in the process of mapping a VMA, which forms the basis of recently observed issues with resource leaks and observable inconsistent state. This series goes to great lengths to simplify how mmap_region() works and to avoid unwinding errors late on in the process of setting up the VMA for the new mapping, and equally avoids such operations occurring while the VMA is in an inconsistent state. The patches in this series comprise the minimal changes required to resolve existing issues in mmap_region() error handling, in order that they can be hotfixed and backported. There is additionally a follow up series which goes further, separated out from the v1 series and sent and updated separately. This patch (of 5): After an attempted mmap() fails, we are no longer in a situation where we can safely interact with VMA hooks. This is currently not enforced, meaning that we need complicated handling to ensure we do not incorrectly call these hooks. We can avoid the whole issue by treating the VMA as suspect the moment that the file->f_ops->mmap() function reports an error by replacing whatever VMA operations were installed with a dummy empty set of VMA operations. We do so through a new helper function internal to mm - mmap_file() - which is both more logically named than the existing call_mmap() function and correctly isolates handling of the vm_op reassignment to mm. All the existing invocations of call_mmap() outside of mm are ultimately nested within the call_mmap() from mm, which we now replace. It is therefore safe to leave call_mmap() in place as a convenience function (and to avoid churn). The invokers are: ovl_file_operations -> mmap -> ovl_mmap() -> backing_file_mmap() coda_file_operations -> mmap -> coda_file_mmap() shm_file_operations -> shm_mmap() shm_file_operations_huge -> shm_mmap() dma_buf_fops -> dma_buf_mmap_internal -> i915_dmabuf_ops -> i915_gem_dmabuf_mmap() None of these callers interact with vm_ops or mappings in a problematic way on error, quickly exiting out. Link: https://lkml.kernel.org/r/cover.1730224667.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/d41fd763496fd0048a962f3fd9407dc72dd4fd86.1730224667.git.lorenzo.stoakes@oracle.com Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes Reported-by: Jann Horn Reviewed-by: Liam R. Howlett Reviewed-by: Vlastimil Babka Reviewed-by: Jann Horn Cc: Andreas Larsson Cc: Catalin Marinas Cc: David S. Miller Cc: Helge Deller Cc: James E.J. Bottomley Cc: Linus Torvalds Cc: Mark Brown Cc: Peter Xu Cc: Will Deacon Cc: Signed-off-by: Andrew Morton Signed-off-by: Lorenzo Stoakes Signed-off-by: Greg Kroah-Hartman

mm: only enforce minimum stack gap size if it's sensible

2024-10-17T13:21:27+00:00

commit 69b50d4351ed924f29e3d46b159e28f70dfc707f upstream. The generic mmap_base code tries to leave a gap between the top of the stack and the mmap base address, but enforces a minimum gap size (MIN_GAP) of 128MB, which is too large on some setups. In particular, on arm tasks without ADDR_LIMIT_32BIT, the STACK_TOP value is less than 128MB, so it's impossible to fit such a gap in. Only enforce this minimum if MIN_GAP < MAX_GAP, as we'd prefer to honour MAX_GAP, which is defined proportionally, so scales better and always leaves us with both _some_ stack space and some room for mmap. This fixes the usercopy KUnit test suite on 32-bit arm, as it doesn't set any personality flags so gets the default (in this case 26-bit) task size. This test can be run with: ./tools/testing/kunit/kunit.py run --arch arm usercopy --make_options LLVM=1 Link: https://lkml.kernel.org/r/20240803074642.1849623-2-davidgow@google.com Fixes: dba79c3df4a2 ("arm: use generic mmap top-down layout and brk randomization") Signed-off-by: David Gow Reviewed-by: Kees Cook Cc: Alexandre Ghiti Cc: Linus Walleij Cc: Luis Chamberlain Cc: Mark Rutland Cc: Russell King Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm: Remove kmem_valid_obj()

2024-08-29T15:30:28+00:00

commit 6e284c55fc0bef7d25fd34d29db11f483da60ea4 upstream. Function kmem_dump_obj() will splat if passed a pointer to a non-slab object. So nothing calls it directly, instead calling kmem_valid_obj() first to determine whether the passed pointer to a valid slab object. This means that merging kmem_valid_obj() into kmem_dump_obj() will make the code more concise. Therefore, convert kmem_dump_obj() to work the same way as vmalloc_dump_obj(), removing the need for the kmem_dump_obj() caller to check kmem_valid_obj(). After this, there are no remaining calls to kmem_valid_obj() anymore, and it can be safely removed. Suggested-by: Matthew Wilcox Signed-off-by: Zhen Lei Reviewed-by: Matthew Wilcox (Oracle) Acked-by: Vlastimil Babka Signed-off-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker Signed-off-by: Greg Kroah-Hartman

rcu: dump vmalloc memory info safely

2023-09-13T07:42:59+00:00

commit c83ad36a18c02c0f51280b50272327807916987f upstream. Currently, for double invoke call_rcu(), will dump rcu_head objects memory info, if the objects is not allocated from the slab allocator, the vmalloc_dump_obj() will be invoke and the vmap_area_lock spinlock need to be held, since the call_rcu() can be invoked in interrupt context, therefore, there is a possibility of spinlock deadlock scenarios. And in Preempt-RT kernel, the rcutorture test also trigger the following lockdep warning: BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 1, name: swapper/0 preempt_count: 1, expected: 0 RCU nest depth: 1, expected: 1 3 locks held by swapper/0/1: #0: ffffffffb534ee80 (fullstop_mutex){+.+.}-{4:4}, at: torture_init_begin+0x24/0xa0 #1: ffffffffb5307940 (rcu_read_lock){....}-{1:3}, at: rcu_torture_init+0x1ec7/0x2370 #2: ffffffffb536af40 (vmap_area_lock){+.+.}-{3:3}, at: find_vmap_area+0x1f/0x70 irq event stamp: 565512 hardirqs last enabled at (565511): [] __call_rcu_common+0x218/0x940 hardirqs last disabled at (565512): [] rcu_torture_init+0x20b2/0x2370 softirqs last enabled at (399112): [] __local_bh_enable_ip+0x126/0x170 softirqs last disabled at (399106): [] inet_register_protosw+0x9/0x1d0 Preemption disabled at: [] rcu_torture_init+0x1f13/0x2370 CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 6.5.0-rc4-rt2-yocto-preempt-rt+ #15 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack_lvl+0x68/0xb0 dump_stack+0x14/0x20 __might_resched+0x1aa/0x280 ? __pfx_rcu_torture_err_cb+0x10/0x10 rt_spin_lock+0x53/0x130 ? find_vmap_area+0x1f/0x70 find_vmap_area+0x1f/0x70 vmalloc_dump_obj+0x20/0x60 mem_dump_obj+0x22/0x90 __call_rcu_common+0x5bf/0x940 ? debug_smp_processor_id+0x1b/0x30 call_rcu_hurry+0x14/0x20 rcu_torture_init+0x1f82/0x2370 ? __pfx_rcu_torture_leak_cb+0x10/0x10 ? __pfx_rcu_torture_leak_cb+0x10/0x10 ? __pfx_rcu_torture_init+0x10/0x10 do_one_initcall+0x6c/0x300 ? debug_smp_processor_id+0x1b/0x30 kernel_init_freeable+0x2b9/0x540 ? __pfx_kernel_init+0x10/0x10 kernel_init+0x1f/0x150 ret_from_fork+0x40/0x50 ? __pfx_kernel_init+0x10/0x10 ret_from_fork_asm+0x1b/0x30 The previous patch fixes this by using the deadlock-safe best-effort version of find_vm_area. However, in case of failure print the fact that the pointer was a vmalloc pointer so that we print at least something. Link: https://lkml.kernel.org/r/20230904180806.1002832-2-joel@joelfernandes.org Fixes: 98f180837a89 ("mm: Make mem_dump_obj() handle vmalloc() memory") Signed-off-by: Zqiang Signed-off-by: Joel Fernandes (Google) Reported-by: Zhen Lei Reviewed-by: Matthew Wilcox (Oracle) Cc: Paul E. McKenney Cc: Uladzislau Rezki (Sony) Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-10-11T00:53:04+00:00

Pull MM updates from Andrew Morton: - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in linux-next for a couple of months without, to my knowledge, any negative reports (or any positive ones, come to that). - Also the Maple Tree from Liam Howlett. An overlapping range-based tree for vmas. It it apparently slightly more efficient in its own right, but is mainly targeted at enabling work to reduce mmap_lock contention. Liam has identified a number of other tree users in the kernel which could be beneficially onverted to mapletrees. Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat at [1]. This has yet to be addressed due to Liam's unfortunately timed vacation. He is now back and we'll get this fixed up. - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses clang-generated instrumentation to detect used-unintialized bugs down to the single bit level. KMSAN keeps finding bugs. New ones, as well as the legacy ones. - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of memory into THPs. - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support file/shmem-backed pages. - userfaultfd updates from Axel Rasmussen - zsmalloc cleanups from Alexey Romanov - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure - Huang Ying adds enhancements to NUMA balancing memory tiering mode's page promotion, with a new way of detecting hot pages. - memcg updates from Shakeel Butt: charging optimizations and reduced memory consumption. - memcg cleanups from Kairui Song. - memcg fixes and cleanups from Johannes Weiner. - Vishal Moola provides more folio conversions - Zhang Yi removed ll_rw_block() :( - migration enhancements from Peter Xu - migration error-path bugfixes from Huang Ying - Aneesh Kumar added ability for a device driver to alter the memory tiering promotion paths. For optimizations by PMEM drivers, DRM drivers, etc. - vma merging improvements from Jakub Matěn. - NUMA hinting cleanups from David Hildenbrand. - xu xin added aditional userspace visibility into KSM merging activity. - THP & KSM code consolidation from Qi Zheng. - more folio work from Matthew Wilcox. - KASAN updates from Andrey Konovalov. - DAMON cleanups from Kaixu Xia. - DAMON work from SeongJae Park: fixes, cleanups. - hugetlb sysfs cleanups from Muchun Song. - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core. Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1] * tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits) hugetlb: allocate vma lock for all sharable vmas hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer hugetlb: fix vma lock handling during split vma and range unmapping mglru: mm/vmscan.c: fix imprecise comments mm/mglru: don't sync disk for each aging cycle mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol mm: memcontrol: use do_memsw_account() in a few more places mm: memcontrol: deprecate swapaccounting=0 mode mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled mm/secretmem: remove reduntant return value mm/hugetlb: add available_huge_pages() func mm: remove unused inline functions from include/linux/mm_inline.h selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd selftests/vm: add thp collapse shmem testing selftests/vm: add thp collapse file and tmpfs testing selftests/vm: modularize thp collapse memory operations selftests/vm: dedup THP helpers mm/khugepaged: add tracepoint to hpage_collapse_scan_file() mm/madvise: add file and shmem support to MADV_COLLAPSE ...

mm: fix BUG splat with kvmalloc + GFP_ATOMIC

2022-10-01T01:46:31+00:00

Martin Zaharinov reports BUG with 5.19.10 kernel: kernel BUG at mm/vmalloc.c:2437! invalid opcode: 0000 [#1] SMP CPU: 28 PID: 0 Comm: swapper/28 Tainted: G W O 5.19.9 #1 [..] RIP: 0010:__get_vm_area_node+0x120/0x130 __vmalloc_node_range+0x96/0x1e0 kvmalloc_node+0x92/0xb0 bucket_table_alloc.isra.0+0x47/0x140 rhashtable_try_insert+0x3a4/0x440 rhashtable_insert_slow+0x1b/0x30 [..] bucket_table_alloc uses kvzalloc(GPF_ATOMIC). If kmalloc fails, this now falls through to vmalloc and hits code paths that assume GFP_KERNEL. Link: https://lkml.kernel.org/r/20220926151650.15293-1-fw@strlen.de Fixes: a421ef303008 ("mm: allow !GFP_KERNEL allocations for kvmalloc") Signed-off-by: Florian Westphal Suggested-by: Michal Hocko Link: https://lore.kernel.org/linux-mm/Yy3MS2uhSgjF47dy@pc636/T/#t Acked-by: Michal Hocko Reported-by: Martin Zaharinov Cc: Uladzislau Rezki (Sony) Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton

mm: remove the vma linked list

2022-09-27T02:46:26+00:00

Replace any vm_next use with vma_find(). Update free_pgtables(), unmap_vmas(), and zap_page_range() to use the maple tree. Use the new free_pgtables() and unmap_vmas() in do_mas_align_munmap(). At the same time, alter the loop to be more compact. Now that free_pgtables() and unmap_vmas() take a maple tree as an argument, rearrange do_mas_align_munmap() to use the new tree to hold the vmas to remove. Remove __vma_link_list() and __vma_unlink_list() as they are exclusively used to update the linked list. Drop linked list update from __insert_vm_struct(). Rework validation of tree as it was depending on the linked list. [yang.lee@linux.alibaba.com: fix one kernel-doc comment] Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=1949 Link: https://lkml.kernel.org/r/20220824021918.94116-1-yang.lee@linux.alibaba.comLink: https://lkml.kernel.org/r/20220906194824.2110408-69-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Signed-off-by: Yang Li Tested-by: Yu Zhao Cc: Catalin Marinas Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: "Matthew Wilcox (Oracle)" Cc: SeongJae Park Cc: Sven Schnelle Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton

mm: remove rb tree.

2022-09-27T02:46:16+00:00

Remove the RB tree and start using the maple tree for vm_area_struct tracking. Drop validate_mm() calls in expand_upwards() and expand_downwards() as the lock is not held. Link: https://lkml.kernel.org/r/20220906194824.2110408-18-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Tested-by: Yu Zhao Cc: Catalin Marinas Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: "Matthew Wilcox (Oracle)" Cc: SeongJae Park Cc: Sven Schnelle Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton

mm/util.c: add warning if __vm_enough_memory fails

2022-09-12T03:25:54+00:00

If a process has not enough memory to allocate a new virtual mapping, we may meet verious kinds of error, eg, fork cannot allocate memory, SIGBUS error in shmem, but it is difficult to confirm them, let's add some debug information to easily to check this scenario if __vm_enough_memory fails. Link: https://lkml.kernel.org/r/20220726145428.8030-1-wangkefeng.wang@huawei.com Reported-by: Yongqiang Liu Signed-off-by: Kefeng Wang Acked-by: David Hildenbrand Signed-off-by: Andrew Morton