kernel.git/mm/shmem.c, branch linux-5.19.y

shmem: update folio if shmem_replace_page() updates the page

2022-08-31T15:18:16Z

commit 9dfb3b8d655022760ca68af11821f1c63aa547c3 upstream. If we allocate a new page, we need to make sure that our folio matches that new page. If we do end up in this code path, we store the wrong page in the shmem inode's page cache, and I would rather imagine that data corruption ensues. This will be solved by changing shmem_replace_page() to shmem_replace_folio(), but this is the minimal fix. Link: https://lkml.kernel.org/r/20220730042518.1264767-1-willy@infradead.org Fixes: da08e9b79323 ("mm/shmem: convert shmem_swapin_page() to shmem_swapin_folio()") Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: William Kucharski Cc: Hugh Dickins Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

tmpfs: fix the issue that the mount and remount results are inconsistent.

2022-07-18T22:07:51Z

An undefined-behavior issue has not been completely fixed since commit d14f5efadd84 ("tmpfs: fix undefined-behaviour in shmem_reconfigure()"). In the commit, check in the shmem_reconfigure() is added in remount process to avoid the Ubsan problem. However, the check is not added to the mount process. It causes inconsistent results between mount and remount. The operations to reproduce the problem in user mode as follows: If nr_blocks is set to 0x8000000000000000, the mounting is successful. # mount tmpfs /dev/shm/ -t tmpfs -o nr_blocks=0x8000000000000000 However, when -o remount is used, the mount fails because of the check in the shmem_reconfigure() # mount tmpfs /dev/shm/ -t tmpfs -o remount,nr_blocks=0x8000000000000000 mount: /dev/shm: mount point not mounted or bad option. Therefore, add checks in the shmem_parse_one() function and remove the check in shmem_reconfigure() to avoid this problem. Link: https://lkml.kernel.org/r/20220629124324.1640807-1-wangzhaolong1@huawei.com Signed-off-by: ZhaoLong Wang Cc: Luo Meng Cc: Hugh Dickins Cc: Yu Kuai Cc: Zhihao Cheng Cc: Zhang Yi Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2022-05-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-05-27T18:40:49Z

Pull more MM updates from Andrew Morton: - Two follow-on fixes for the post-5.19 series "Use pageblock_order for cma and alloc_contig_range alignment", from Zi Yan. - A series of z3fold cleanups and fixes from Miaohe Lin. - Some memcg selftests work from Michal Koutný - Some swap fixes and cleanups from Miaohe Lin - Several individual minor fixups * tag 'mm-stable-2022-05-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (25 commits) mm/shmem.c: suppress shift warning mm: Kconfig: reorganize misplaced mm options mm: kasan: fix input of vmalloc_to_page() mm: fix is_pinnable_page against a cma page mm: filter out swapin error entry in shmem mapping mm/shmem: fix infinite loop when swap in shmem error at swapoff time mm/madvise: free hwpoison and swapin error entry in madvise_free_pte_range mm/swapfile: fix lost swap bits in unuse_pte() mm/swapfile: unuse_pte can map random data if swap read fails selftests: memcg: factor out common parts of memory.{low,min} tests selftests: memcg: remove protection from top level memcg selftests: memcg: adjust expected reclaim values of protected cgroups selftests: memcg: expect no low events in unprotected sibling selftests: memcg: fix compilation mm/z3fold: fix z3fold_page_migrate races with z3fold_map mm/z3fold: fix z3fold_reclaim_page races with z3fold_free mm/z3fold: always clear PAGE_CLAIMED under z3fold page lock mm/z3fold: put z3fold page back into unbuddied list when reclaim or migration fails revert "mm/z3fold.c: allow __GFP_HIGHMEM in z3fold_alloc" mm/z3fold: throw warning on failure of trylock_page in z3fold_alloc ...

mm/shmem.c: suppress shift warning

2022-05-27T16:33:47Z

mm/shmem.c:1948 shmem_getpage_gfp() warn: should '(((1) << 12) / 512) << folio_order(folio)' be a 64 bit type? On i386, so an unsigned long is 32-bit, but i_blocks is a 64-bit blkcnt_t. Reported-by: kernel test robot Reported-by: Jessica Clarke Signed-off-by: Andrew Morton

mm/shmem: fix infinite loop when swap in shmem error at swapoff time

2022-05-27T16:33:46Z

When swap in shmem error at swapoff time, there would be a infinite loop in the while loop in shmem_unuse_inode(). It's because swapin error is deliberately ignored now and thus info->swapped will never reach 0. So we can't escape the loop in shmem_unuse(). In order to fix the issue, swapin_error entry is stored in the mapping when swapin error occurs. So the swapcache page can be freed and the user won't end up with a permanently mounted swap because a sector is bad. If the page is accessed later, the user process will be killed so that corrupted data is never consumed. On the other hand, if the page is never accessed, the user won't even notice it. Link: https://lkml.kernel.org/r/20220519125030.21486-5-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Reported-by: Naoya Horiguchi Reviewed-by: Naoya Horiguchi Cc: Alistair Popple Cc: David Hildenbrand Cc: David Howells Cc: Hugh Dickins Cc: Matthew Wilcox (Oracle) Cc: NeilBrown Cc: Peter Xu Cc: Ralph Campbell Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2022-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-05-26T19:32:41Z

Pull MM updates from Andrew Morton: "Almost all of MM here. A few things are still getting finished off, reviewed, etc. - Yang Shi has improved the behaviour of khugepaged collapsing of readonly file-backed transparent hugepages. - Johannes Weiner has arranged for zswap memory use to be tracked and managed on a per-cgroup basis. - Munchun Song adds a /proc knob ("hugetlb_optimize_vmemmap") for runtime enablement of the recent huge page vmemmap optimization feature. - Baolin Wang contributes a series to fix some issues around hugetlb pagetable invalidation. - Zhenwei Pi has fixed some interactions between hwpoisoned pages and virtualization. - Tong Tiangen has enabled the use of the presently x86-only page_table_check debugging feature on arm64 and riscv. - David Vernet has done some fixup work on the memcg selftests. - Peter Xu has taught userfaultfd to handle write protection faults against shmem- and hugetlbfs-backed files. - More DAMON development from SeongJae Park - adding online tuning of the feature and support for monitoring of fixed virtual address ranges. Also easier discovery of which monitoring operations are available. - Nadav Amit has done some optimization of TLB flushing during mprotect(). - Neil Brown continues to labor away at improving our swap-over-NFS support. - David Hildenbrand has some fixes to anon page COWing versus get_user_pages(). - Peng Liu fixed some errors in the core hugetlb code. - Joao Martins has reduced the amount of memory consumed by device-dax's compound devmaps. - Some cleanups of the arch-specific pagemap code from Anshuman Khandual. - Muchun Song has found and fixed some errors in the TLB flushing of transparent hugepages. - Roman Gushchin has done more work on the memcg selftests. ... and, of course, many smaller fixes and cleanups. Notably, the customary million cleanup serieses from Miaohe Lin" * tag 'mm-stable-2022-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (381 commits) mm: kfence: use PAGE_ALIGNED helper selftests: vm: add the "settings" file with timeout variable selftests: vm: add "test_hmm.sh" to TEST_FILES selftests: vm: check numa_available() before operating "merge_across_nodes" in ksm_tests selftests: vm: add migration to the .gitignore selftests/vm/pkeys: fix typo in comment ksm: fix typo in comment selftests: vm: add process_mrelease tests Revert "mm/vmscan: never demote for memcg reclaim" mm/kfence: print disabling or re-enabling message include/trace/events/percpu.h: cleanup for "percpu: improve percpu_alloc_percpu event trace" include/trace/events/mmflags.h: cleanup for "tracing: incorrect gfp_t conversion" mm: fix a potential infinite loop in start_isolate_page_range() MAINTAINERS: add Muchun as co-maintainer for HugeTLB zram: fix Kconfig dependency warning mm/shmem: fix shmem folio swapoff hang cgroup: fix an error handling path in alloc_pagecache_max_30M() mm: damon: use HPAGE_PMD_SIZE tracing: incorrect isolate_mote_t cast in mm_vmscan_lru_isolate nodemask.h: fix compilation error with GCC12 ...

mm/shmem: fix shmem folio swapoff hang

2022-05-25T17:47:47Z

Shmem swapoff makes no progress: the index to indices is not incremented. But "ret" is no longer a return value, so use folio_batch_count() instead. Link: https://lkml.kernel.org/r/c32bee8a-f0aa-245-f94e-24dd271924fa@google.com Fixes: da08e9b79323 ("mm/shmem: convert shmem_swapin_page() to shmem_swapin_folio()") Signed-off-by: Hugh Dickins Reviewed-by: Miaohe Lin Tested-by: Miaohe Lin Cc: Matthew Wilcox Cc: Christoph Hellwig Signed-off-by: Andrew Morton

tmpfs: fix undefined-behaviour in shmem_reconfigure()

2022-05-19T21:08:54Z

When shmem_reconfigure() calls __percpu_counter_compare(), the second parameter is unsigned long long. But in the definition of __percpu_counter_compare(), the second parameter is s64. So when __percpu_counter_compare() executes abs(count - rhs), UBSAN shows the following warning: ================================================================================ UBSAN: Undefined behaviour in lib/percpu_counter.c:209:6 signed integer overflow: 0 - -9223372036854775808 cannot be represented in type 'long long int' CPU: 1 PID: 9636 Comm: syz-executor.2 Tainted: G ---------r- - 4.18.0 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack home/install/linux-rh-3-10/lib/dump_stack.c:77 [inline] dump_stack+0x125/0x1ae home/install/linux-rh-3-10/lib/dump_stack.c:117 ubsan_epilogue+0xe/0x81 home/install/linux-rh-3-10/lib/ubsan.c:159 handle_overflow+0x19d/0x1ec home/install/linux-rh-3-10/lib/ubsan.c:190 __percpu_counter_compare+0x124/0x140 home/install/linux-rh-3-10/lib/percpu_counter.c:209 percpu_counter_compare home/install/linux-rh-3-10/./include/linux/percpu_counter.h:50 [inline] shmem_remount_fs+0x1ce/0x6b0 home/install/linux-rh-3-10/mm/shmem.c:3530 do_remount_sb+0x11b/0x530 home/install/linux-rh-3-10/fs/super.c:888 do_remount home/install/linux-rh-3-10/fs/namespace.c:2344 [inline] do_mount+0xf8d/0x26b0 home/install/linux-rh-3-10/fs/namespace.c:2844 ksys_mount+0xad/0x120 home/install/linux-rh-3-10/fs/namespace.c:3075 __do_sys_mount home/install/linux-rh-3-10/fs/namespace.c:3089 [inline] __se_sys_mount home/install/linux-rh-3-10/fs/namespace.c:3086 [inline] __x64_sys_mount+0xbf/0x160 home/install/linux-rh-3-10/fs/namespace.c:3086 do_syscall_64+0xca/0x5c0 home/install/linux-rh-3-10/arch/x86/entry/common.c:298 entry_SYSCALL_64_after_hwframe+0x6a/0xdf RIP: 0033:0x46b5e9 Code: 5d db fa ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 2b db fa ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f54d5f22c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 000000000077bf60 RCX: 000000000046b5e9 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000000 RBP: 000000000077bf60 R08: 0000000020000140 R09: 0000000000000000 R10: 00000000026740a4 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd1fb1592f R14: 00007f54d5f239c0 R15: 000000000077bf6c ================================================================================ [akpm@linux-foundation.org: tweak error message text] Link: https://lkml.kernel.org/r/20220513025225.2678727-1-luomeng12@huawei.com Signed-off-by: Luo Meng Cc: Hugh Dickins Cc: Yu Kuai Signed-off-by: Andrew Morton

mm: mmap: register suitable readonly file vmas for khugepaged

2022-05-19T21:08:50Z

The readonly FS THP relies on khugepaged to collapse THP for suitable vmas. But the behavior is inconsistent for "always" mode (https://lore.kernel.org/linux-mm/00f195d4-d039-3cf2-d3a1-a2c88de397a0@suse.cz/). The "always" mode means THP allocation should be tried all the time and khugepaged should try to collapse THP all the time. Of course the allocation and collapse may fail due to other factors and conditions. Currently file THP may not be collapsed by khugepaged even though all the conditions are met. That does break the semantics of "always" mode. So make sure readonly FS vmas are registered to khugepaged to fix the break. Register suitable vmas in common mmap path, that could cover both readonly FS vmas and shmem vmas, so remove the khugepaged calls in shmem.c. Still need to keep the khugepaged call in vma_merge() since vma_merge() is called in a lot of places, for example, madvise, mprotect, etc. Link: https://lkml.kernel.org/r/20220510203222.24246-9-shy828301@gmail.com Signed-off-by: Yang Shi Reported-by: Vlastimil Babka Acked-by: Vlastmil Babka Cc: Kirill A. Shutemov Cc: Miaohe Lin Cc: Song Liu Cc: Rik van Riel Cc: Matthew Wilcox (Oracle) Cc: Zi Yan Cc: Theodore Ts'o Cc: Song Liu Signed-off-by: Andrew Morton

mm: khugepaged: introduce khugepaged_enter_vma() helper

2022-05-19T21:08:50Z

The khugepaged_enter_vma_merge() actually does as the same thing as the khugepaged_enter() section called by shmem_mmap(), so consolidate them into one helper and rename it to khugepaged_enter_vma(). Link: https://lkml.kernel.org/r/20220510203222.24246-8-shy828301@gmail.com Signed-off-by: Yang Shi Acked-by: Vlastmil Babka Cc: Kirill A. Shutemov Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Rik van Riel Cc: Song Liu Cc: Song Liu Cc: Theodore Ts'o Cc: Zi Yan Signed-off-by: Andrew Morton