kernel/linux.git/mm/memory.c, branch linux-5.17.y

mm: hugetlb: fix missing cache flush in copy_huge_page_from_user()

2022-05-15T18:20:52+00:00

commit e763243cc6cb1fcc720ec58cfd6e7c35ae90a479 upstream. userfaultfd calls copy_huge_page_from_user() which does not do any cache flushing for the target page. Then the target page will be mapped to the user space with a different address (user address), which might have an alias issue with the kernel address used to copy the data from the user to. Fix this issue by flushing dcache in copy_huge_page_from_user(). Link: https://lkml.kernel.org/r/20220210123058.79206-4-songmuchun@bytedance.com Fixes: fa4d75c1de13 ("userfaultfd: hugetlbfs: add copy_huge_page_from_user for hugetlb userfaultfd support") Signed-off-by: Muchun Song Reviewed-by: Mike Kravetz Cc: Axel Rasmussen Cc: David Rientjes Cc: Fam Zheng Cc: Kirill A. Shutemov Cc: Lars Persson Cc: Peter Xu Cc: Xiongchun Duan Cc: Zi Yan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm,hwpoison: unmap poisoned page before invalidation

2022-04-08T11:57:23+00:00

commit 3149c79f3cb0e2e3bafb7cfadacec090cbd250d3 upstream. In some cases it appears the invalidation of a hwpoisoned page fails because the page is still mapped in another process. This can cause a program to be continuously restarted and die when it page faults on the page that was not invalidated. Avoid that problem by unmapping the hwpoisoned page when we find it. Another issue is that sometimes we end up oopsing in finish_fault, if the code tries to do something with the now-NULL vmf->page. I did not hit this error when submitting the previous patch because there are several opportunities for alloc_set_pte to bail out before accessing vmf->page, and that apparently happened on those systems, and most of the time on other systems, too. However, across several million systems that error does occur a handful of times a day. It can be avoided by returning VM_FAULT_NOPAGE which will cause do_read_fault to return before calling finish_fault. Link: https://lkml.kernel.org/r/20220325161428.5068d97e@imladris.surriel.com Fixes: e53ac7374e64 ("mm: invalidate hwpoison page cache page in fault path") Signed-off-by: Rik van Riel Reviewed-by: Miaohe Lin Tested-by: Naoya Horiguchi Reviewed-by: Oscar Salvador Cc: Mel Gorman Cc: Johannes Weiner Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm: invalidate hwpoison page cache page in fault path

2022-04-08T11:57:20+00:00

commit e53ac7374e64dede04d745ff0e70ff5048378d1f upstream. Sometimes the page offlining code can leave behind a hwpoisoned clean page cache page. This can lead to programs being killed over and over and over again as they fault in the hwpoisoned page, get killed, and then get re-spawned by whatever wanted to run them. This is particularly embarrassing when the page was offlined due to having too many corrected memory errors. Now we are killing tasks due to them trying to access memory that probably isn't even corrupted. This problem can be avoided by invalidating the page from the page fault handler, which already has a branch for dealing with these kinds of pages. With this patch we simply pretend the page fault was successful if the page was invalidated, return to userspace, incur another page fault, read in the file from disk (to a new memory page), and then everything works again. Link: https://lkml.kernel.org/r/20220212213740.423efcea@imladris.surriel.com Signed-off-by: Rik van Riel Reviewed-by: Miaohe Lin Acked-by: Naoya Horiguchi Reviewed-by: Oscar Salvador Cc: John Hubbard Cc: Mel Gorman Cc: Johannes Weiner Cc: Matthew Wilcox Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm: don't skip swap entry even if zap_details specified

2022-04-08T11:57:19+00:00

commit 5abfd71d936a8aefd9f9ccd299dea7a164a5d455 upstream. Patch series "mm: Rework zap ptes on swap entries", v5. Patch 1 should fix a long standing bug for zap_pte_range() on zap_details usage. The risk is we could have some swap entries skipped while we should have zapped them. Migration entries are not the major concern because file backed memory always zap in the pattern that "first time without page lock, then re-zap with page lock" hence the 2nd zap will always make sure all migration entries are already recovered. However there can be issues with real swap entries got skipped errornoously. There's a reproducer provided in commit message of patch 1 for that. Patch 2-4 are cleanups that are based on patch 1. After the whole patchset applied, we should have a very clean view of zap_pte_range(). Only patch 1 needs to be backported to stable if necessary. This patch (of 4): The "details" pointer shouldn't be the token to decide whether we should skip swap entries. For example, when the callers specified details->zap_mapping==NULL, it means the user wants to zap all the pages (including COWed pages), then we need to look into swap entries because there can be private COWed pages that was swapped out. Skipping some swap entries when details is non-NULL may lead to wrongly leaving some of the swap entries while we should have zapped them. A reproducer of the problem: ===8<=== #define _GNU_SOURCE /* See feature_test_macros(7) */ #include #include #include #include #include int page_size; int shmem_fd; char *buffer; void main(void) { int ret; char val; page_size = getpagesize(); shmem_fd = memfd_create("test", 0); assert(shmem_fd >= 0); ret = ftruncate(shmem_fd, page_size * 2); assert(ret == 0); buffer = mmap(NULL, page_size * 2, PROT_READ | PROT_WRITE, MAP_PRIVATE, shmem_fd, 0); assert(buffer != MAP_FAILED); /* Write private page, swap it out */ buffer[page_size] = 1; madvise(buffer, page_size * 2, MADV_PAGEOUT); /* This should drop private buffer[page_size] already */ ret = ftruncate(shmem_fd, page_size); assert(ret == 0); /* Recover the size */ ret = ftruncate(shmem_fd, page_size * 2); assert(ret == 0); /* Re-read the data, it should be all zero */ val = buffer[page_size]; if (val == 0) printf("Good\n"); else printf("BUG\n"); } ===8<=== We don't need to touch up the pmd path, because pmd never had a issue with swap entries. For example, shmem pmd migration will always be split into pte level, and same to swapping on anonymous. Add another helper should_zap_cows() so that we can also check whether we should zap private mappings when there's no page pointer specified. This patch drops that trick, so we handle swap ptes coherently. Meanwhile we should do the same check upon migration entry, hwpoison entry and genuine swap entries too. To be explicit, we should still remember to keep the private entries if even_cows==false, and always zap them when even_cows==true. The issue seems to exist starting from the initial commit of git. [peterx@redhat.com: comment tweaks] Link: https://lkml.kernel.org/r/20220217060746.71256-2-peterx@redhat.com Link: https://lkml.kernel.org/r/20220217060746.71256-1-peterx@redhat.com Link: https://lkml.kernel.org/r/20220216094810.60572-1-peterx@redhat.com Link: https://lkml.kernel.org/r/20220216094810.60572-2-peterx@redhat.com Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Peter Xu Reviewed-by: John Hubbard Cc: David Hildenbrand Cc: Hugh Dickins Cc: Alistair Popple Cc: Andrea Arcangeli Cc: "Kirill A . Shutemov" Cc: Matthew Wilcox Cc: Vlastimil Babka Cc: Yang Shi Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

Merge branch 'akpm' (patches from Andrew)

2022-01-20T08:41:01+00:00

Merge more updates from Andrew Morton: "55 patches. Subsystems affected by this patch series: percpu, procfs, sysctl, misc, core-kernel, get_maintainer, lib, checkpatch, binfmt, nilfs2, hfs, fat, adfs, panic, delayacct, kconfig, kcov, and ubsan" * emailed patches from Andrew Morton : (55 commits) lib: remove redundant assignment to variable ret ubsan: remove CONFIG_UBSAN_OBJECT_SIZE kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR lib/Kconfig.debug: make TEST_KMOD depend on PAGE_SIZE_LESS_THAN_256KB btrfs: use generic Kconfig option for 256kB page size limit arch/Kconfig: split PAGE_SIZE_LESS_THAN_256KB from PAGE_SIZE_LESS_THAN_64KB configs: introduce debug.config for CI-like setup delayacct: track delays from memory compact Documentation/accounting/delay-accounting.rst: add thrashing page cache and direct compact delayacct: cleanup flags in struct task_delay_info and functions use it delayacct: fix incomplete disable operation when switch enable to disable delayacct: support swapin delay accounting for swapping without blkio panic: remove oops_id panic: use error_report_end tracepoint on warnings fs/adfs: remove unneeded variable make code cleaner FAT: use io_schedule_timeout() instead of congestion_wait() hfsplus: use struct_group_attr() for memcpy() region nilfs2: remove redundant pointer sbufs fs/binfmt_elf: use PT_LOAD p_align values for static PIE const_structs.checkpatch: add frequently used ops structs ...

delayacct: support swapin delay accounting for swapping without blkio

2022-01-20T06:52:55+00:00

Currently delayacct accounts swapin delay only for swapping that cause blkio. If we use zram for swapping, tools/accounting/getdelays can't get any SWAP delay. It's useful to get zram swapin delay information, for example to adjust compress algorithm or /proc/sys/vm/swappiness. Reference to PSI, it accounts any kind of swapping by doing its work in swap_readpage(), no matter whether swapping causes blkio. Let delayacct do the similar work. Link: https://lkml.kernel.org/r/20211112083813.8559-1-yang.yang29@zte.com.cn Signed-off-by: Yang Yang Reported-by: Zeal Robot Cc: Balbir Singh Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'akpm' (patches from Andrew)

2022-01-15T18:37:06+00:00

Merge misc updates from Andrew Morton: "146 patches. Subsystems affected by this patch series: kthread, ia64, scripts, ntfs, squashfs, ocfs2, vfs, and mm (slab-generic, slab, kmemleak, dax, kasan, debug, pagecache, gup, shmem, frontswap, memremap, memcg, selftests, pagemap, dma, vmalloc, memory-failure, hugetlb, userfaultfd, vmscan, mempolicy, oom-kill, hugetlbfs, migration, thp, ksm, page-poison, percpu, rmap, zswap, zram, cleanups, hmm, and damon)" * emailed patches from Andrew Morton : (146 commits) mm/damon: hide kernel pointer from tracepoint event mm/damon/vaddr: hide kernel pointer from damon_va_three_regions() failure log mm/damon/vaddr: use pr_debug() for damon_va_three_regions() failure logging mm/damon/dbgfs: remove an unnecessary variable mm/damon: move the implementation of damon_insert_region to damon.h mm/damon: add access checking for hugetlb pages Docs/admin-guide/mm/damon/usage: update for schemes statistics mm/damon/dbgfs: support all DAMOS stats Docs/admin-guide/mm/damon/reclaim: document statistics parameters mm/damon/reclaim: provide reclamation statistics mm/damon/schemes: account how many times quota limit has exceeded mm/damon/schemes: account scheme actions that successfully applied mm/damon: remove a mistakenly added comment for a future feature Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts Docs/admin-guide/mm/damon/usage: mention tracepoint at the beginning Docs/admin-guide/mm/damon/usage: remove redundant information Docs/admin-guide/mm/damon/usage: update for scheme quotas and watermarks mm/damon: convert macro functions to static inline functions mm/damon: modify damon_rand() macro to static inline function mm/damon: move damon_rand() definition into damon.h ...

mm: remove last argument of reuse_swap_page()

2022-01-15T14:30:28+00:00

None of the callers care about the total_map_swapcount() any more. Link: https://lkml.kernel.org/r/20211220205943.456187-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Acked-by: Linus Torvalds Reviewed-by: William Kucharski Reviewed-by: David Hildenbrand Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: change page type prior to adding page table entry

2022-01-15T14:30:28+00:00

Patch series "page table check", v3. Ensure that some memory corruptions are prevented by checking at the time of insertion of entries into user page tables that there is no illegal sharing. We have recently found a problem [1] that existed in kernel since 4.14. The problem was caused by broken page ref count and led to memory leaking from one process into another. The problem was accidentally detected by studying a dump of one process and noticing that one page contains memory that should not belong to this process. There are some other page->_refcount related problems that were recently fixed: [2], [3] which potentially could also lead to illegal sharing. In addition to hardening refcount [4] itself, this work is an attempt to prevent this class of memory corruption issues. It uses a simple state machine that is independent from regular MM logic to check for illegal sharing at time pages are inserted and removed from page tables. [1] https://lore.kernel.org/all/xr9335nxwc5y.fsf@gthelen2.svl.corp.google.com [2] https://lore.kernel.org/all/1582661774-30925-2-git-send-email-akaher@vmware.com [3] https://lore.kernel.org/all/20210622021423.154662-3-mike.kravetz@oracle.com [4] https://lore.kernel.org/all/20211221150140.988298-1-pasha.tatashin@soleen.com This patch (of 4): There are a few places where we first update the entry in the user page table, and later change the struct page to indicate that this is anonymous or file page. In most places, however, we first configure the page metadata and then insert entries into the page table. Page table check, will use the information from struct page to verify the type of entry is inserted. Change the order in all places to first update struct page, and later to update page table. This means that we first do calls that may change the type of page (anon or file): page_move_anon_rmap page_add_anon_rmap do_page_add_anon_rmap page_add_new_anon_rmap page_add_file_rmap hugepage_add_anon_rmap hugepage_add_new_anon_rmap And after that do calls that add entries to the page table: set_huge_pte_at set_pte_at Link: https://lkml.kernel.org/r/20211221154650.1047963-1-pasha.tatashin@soleen.com Link: https://lkml.kernel.org/r/20211221154650.1047963-2-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin Cc: David Rientjes Cc: Paul Turner Cc: Wei Xu Cc: Greg Thelen Cc: Ingo Molnar Cc: Jonathan Corbet Cc: Will Deacon Cc: Mike Rapoport Cc: Kees Cook Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Masahiro Yamada Cc: Sami Tolvanen Cc: Dave Hansen Cc: Frederic Weisbecker Cc: "H. Peter Anvin" Cc: Aneesh Kumar K.V Cc: Jiri Slaby Cc: Muchun Song Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: move tlb_flush_pending inline helpers to mm_inline.h

2022-01-15T14:30:27+00:00

linux/mm_types.h should only define structure definitions, to make it cheap to include elsewhere. The atomic_t helper function definitions are particularly large, so it's better to move the helpers using those into the existing linux/mm_inline.h and only include that where needed. As a follow-up, we may want to go through all the indirect includes in mm_types.h and reduce them as much as possible. Link: https://lkml.kernel.org/r/20211207125710.2503446-2-arnd@kernel.org Signed-off-by: Arnd Bergmann Cc: Al Viro Cc: Stephen Rothwell Cc: Suren Baghdasaryan Cc: Colin Cross Cc: Kees Cook Cc: Peter Xu Cc: Peter Zijlstra (Intel) Cc: Yu Zhao Cc: Vlastimil Babka Cc: Matthew Wilcox (Oracle) Cc: Eric Biederman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds