From 38f1d4aefdac30600698ab07cb1e41fca5851f7a Mon Sep 17 00:00:00 2001 From: Matti Vaittinen Date: Thu, 1 Dec 2022 18:45:40 +0200 Subject: [PATCH 1/9] mailmap: update Matti Vaittinen's email address The email backend used by ROHM keeps labeling patches as spam. This can result in missing the patches. Switch my mail address from a company mail to a personal one. Link: https://lkml.kernel.org/r/8f4498b66fedcbded37b3b87e0c516e659f8f583.1669912977.git.mazziesaccount@gmail.com Signed-off-by: Matti Vaittinen Suggested-by: Krzysztof Kozlowski Cc: Anup Patel Cc: Arnd Bergmann Cc: Atish Patra Cc: Baolin Wang Cc: Ben Widawsky Cc: Bjorn Andersson Cc: Christian Brauner Cc: Colin Ian King Cc: Kirill Tkhai Cc: Qais Yousef Cc: Vasily Averin Signed-off-by: Andrew Morton --- .mailmap | 1 + 1 file changed, 1 insertion(+) diff --git a/.mailmap b/.mailmap index aec51726551f..315e2207439a 100644 --- a/.mailmap +++ b/.mailmap @@ -287,6 +287,7 @@ Matthew Wilcox Matthew Wilcox Matthias Fuchs Matthieu CASTET +Matti Vaittinen Matt Ranostay Matt Ranostay Matthew Ranostay Matt Ranostay From f5ad5083404bb56c9de777dccb68c6672ef6487e Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Fri, 2 Dec 2022 17:27:24 +0100 Subject: [PATCH 2/9] mm: do not BUG_ON missing brk mapping, because userspace can unmap it The following program will trigger the BUG_ON that this patch removes, because the user can munmap() mm->brk: #include #include #include #include static void *brk_now(void) { return (void *)syscall(SYS_brk, 0); } static void brk_set(void *b) { assert(syscall(SYS_brk, b) != -1); } int main(int argc, char *argv[]) { void *b = brk_now(); brk_set(b + 4096); assert(munmap(b - 4096, 4096 * 2) == 0); brk_set(b); return 0; } Compile that with musl, since glibc actually uses brk(), and then execute it, and it'll hit this splat: kernel BUG at mm/mmap.c:229! invalid opcode: 0000 [#1] PREEMPT SMP CPU: 12 PID: 1379 Comm: a.out Tainted: G S U 6.1.0-rc7+ #419 RIP: 0010:__do_sys_brk+0x2fc/0x340 Code: 00 00 4c 89 ef e8 04 d3 fe ff eb 9a be 01 00 00 00 4c 89 ff e8 35 e0 fe ff e9 6e ff ff ff 4d 89 a7 20> RSP: 0018:ffff888140bc7eb0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 00000000007e7000 RCX: ffff8881020fe000 RDX: ffff8881020fe001 RSI: ffff8881955c9b00 RDI: ffff8881955c9b08 RBP: 0000000000000000 R08: ffff8881955c9b00 R09: 00007ffc77844000 R10: 0000000000000000 R11: 0000000000000001 R12: 00000000007e8000 R13: 00000000007e8000 R14: 00000000007e7000 R15: ffff8881020fe000 FS: 0000000000604298(0000) GS:ffff88901f700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000603fe0 CR3: 000000015ba9a005 CR4: 0000000000770ee0 PKRU: 55555554 Call Trace: do_syscall_64+0x2b/0x50 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x400678 Code: 10 4c 8d 41 08 4c 89 44 24 10 4c 8b 01 8b 4c 24 08 83 f9 2f 77 0a 4c 8d 4c 24 20 4c 01 c9 eb 05 48 8b> RSP: 002b:00007ffc77863890 EFLAGS: 00000212 ORIG_RAX: 000000000000000c RAX: ffffffffffffffda RBX: 000000000040031b RCX: 0000000000400678 RDX: 00000000004006a1 RSI: 00000000007e6000 RDI: 00000000007e7000 RBP: 00007ffc77863900 R08: 0000000000000000 R09: 00000000007e6000 R10: 00007ffc77863930 R11: 0000000000000212 R12: 00007ffc77863978 R13: 00007ffc77863988 R14: 0000000000000000 R15: 0000000000000000 Instead, just return the old brk value if the original mapping has been removed. [akpm@linux-foundation.org: fix changelog, per Liam] Link: https://lkml.kernel.org/r/20221202162724.2009-1-Jason@zx2c4.com Fixes: 2e7ce7d354f2 ("mm/mmap: change do_brk_flags() to expand existing VMA and add do_brk_munmap()") Signed-off-by: Jason A. Donenfeld Acked-by: Vlastimil Babka Reviewed-by: Liam R. Howlett Reviewed-by: SeongJae Park Cc: Yu Zhao Cc: Catalin Marinas Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: Matthew Wilcox Cc: Sven Schnelle Cc: Will Deacon Cc: Jann Horn Signed-off-by: Andrew Morton --- mm/mmap.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 74a84eb33b90..0024e615d069 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -226,8 +226,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) /* Search one past newbrk */ mas_set(&mas, newbrk); brkvma = mas_find(&mas, oldbrk); - BUG_ON(brkvma == NULL); - if (brkvma->vm_start >= oldbrk) + if (!brkvma || brkvma->vm_start >= oldbrk) goto out; /* mapping intersects with an existing non-brk vma. */ /* * mm->brk must be protected by write mmap_lock. From de16d6e4a9fb13d07c88d0e57754348662f53b23 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Fri, 2 Dec 2022 09:50:26 +0100 Subject: [PATCH 3/9] kselftests: cgroup: update kmem test precision tolerance MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 1813e51eece0 ("memcg: increase MEMCG_CHARGE_BATCH to 64") has changed the batch size while this test case has been left behind. This has led to a test failure reported by test bot: not ok 2 selftests: cgroup: test_kmem # exit=1 Update the tolerance for the pcp charges to reflect the MEMCG_CHARGE_BATCH change to fix this. [akpm@linux-foundation.org: update comments, per Roman] Link: https://lkml.kernel.org/r/Y4m8Unt6FhWKC6IH@dhcp22.suse.cz Fixes: 1813e51eece0a ("memcg: increase MEMCG_CHARGE_BATCH to 64") Signed-off-by: Michal Hocko Reported-by: kernel test robot Link: https://lore.kernel.org/oe-lkp/202212010958.c1053bd3-yujie.liu@intel.com Acked-by: Shakeel Butt Acked-by: Roman Gushchin Tested-by: Yujie Liu Cc: Eric Dumazet Cc: Feng Tang Cc: Johannes Weiner Cc: "Michal Koutný" Cc: Muchun Song Cc: Soheil Hassas Yeganeh Signed-off-by: Andrew Morton --- tools/testing/selftests/cgroup/test_kmem.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/cgroup/test_kmem.c b/tools/testing/selftests/cgroup/test_kmem.c index 22b31ebb3513..258ddc565deb 100644 --- a/tools/testing/selftests/cgroup/test_kmem.c +++ b/tools/testing/selftests/cgroup/test_kmem.c @@ -19,12 +19,12 @@ /* - * Memory cgroup charging is performed using percpu batches 32 pages + * Memory cgroup charging is performed using percpu batches 64 pages * big (look at MEMCG_CHARGE_BATCH), whereas memory.stat is exact. So * the maximum discrepancy between charge and vmstat entries is number - * of cpus multiplied by 32 pages. + * of cpus multiplied by 64 pages. */ -#define MAX_VMSTAT_ERROR (4096 * 32 * get_nprocs()) +#define MAX_VMSTAT_ERROR (4096 * 64 * get_nprocs()) static int alloc_dcache(const char *cgroup, void *arg) From 44bcabd70cf1425b4243e02251c02b01638a8287 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Sun, 4 Dec 2022 16:51:50 -0800 Subject: [PATCH 4/9] tmpfs: fix data loss from failed fallocate Fix tmpfs data loss when the fallocate system call is interrupted by a signal, or fails for some other reason. The partial folio handling in shmem_undo_range() forgot to consider this unfalloc case, and was liable to erase or truncate out data which had already been committed earlier. It turns out that none of the partial folio handling there is appropriate for the unfalloc case, which just wants to proceed to removal of whole folios: which find_get_entries() provides, even when partially covered. Original patch by Rui Wang. Link: https://lore.kernel.org/linux-mm/33b85d82.7764.1842e9ab207.Coremail.chenguoqic@163.com/ Link: https://lkml.kernel.org/r/a5dac112-cf4b-7af-a33-f386e347fd38@google.com Fixes: b9a8a4195c7d ("truncate,shmem: Handle truncates that split large folios") Signed-off-by: Hugh Dickins Reported-by: Guoqi Chen Link: https://lore.kernel.org/all/20221101032248.819360-1-kernel@hev.cc/ Cc: Rui Wang Cc: Huacai Chen Cc: Matthew Wilcox Cc: Vishal Moola (Oracle) Cc: [5.17+] Signed-off-by: Andrew Morton --- mm/shmem.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/mm/shmem.c b/mm/shmem.c index c1d8b8a1aa3b..82911fefc2d5 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -948,6 +948,15 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, index++; } + /* + * When undoing a failed fallocate, we want none of the partial folio + * zeroing and splitting below, but shall want to truncate the whole + * folio when !uptodate indicates that it was added by this fallocate, + * even when [lstart, lend] covers only a part of the folio. + */ + if (unfalloc) + goto whole_folios; + same_folio = (lstart >> PAGE_SHIFT) == (lend >> PAGE_SHIFT); folio = shmem_get_partial_folio(inode, lstart >> PAGE_SHIFT); if (folio) { @@ -973,6 +982,8 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, folio_put(folio); } +whole_folios: + index = start; while (index < end) { cond_resched(); From 630dc25e43dacfb5af94cd41532e77c47ec1caff Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 5 Dec 2022 16:08:57 +0100 Subject: [PATCH 5/9] mm/swap: fix SWP_PFN_BITS with CONFIG_PHYS_ADDR_T_64BIT on 32bit We use "unsigned long" to store a PFN in the kernel and phys_addr_t to store a physical address. On a 64bit system, both are 64bit wide. However, on a 32bit system, the latter might be 64bit wide. This is, for example, the case on x86 with PAE: phys_addr_t and PTEs are 64bit wide, while "unsigned long" only spans 32bit. The current definition of SWP_PFN_BITS without MAX_PHYSMEM_BITS misses that case, and assumes that the maximum PFN is limited by an 32bit phys_addr_t. This implies, that SWP_PFN_BITS will currently only be able to cover 4 GiB - 1 on any 32bit system with 4k page size, which is wrong. Let's rely on the number of bits in phys_addr_t instead, but make sure to not exceed the maximum swap offset, to not make the BUILD_BUG_ON() in is_pfn_swap_entry() unhappy. Note that swp_entry_t is effectively an unsigned long and the maximum swap offset shares that value with the swap type. For example, on an 8 GiB x86 PAE system with a kernel config based on Debian 11.5 (-> CONFIG_FLATMEM=y, CONFIG_X86_PAE=y), we will currently fail removing migration entries (remove_migration_ptes()), because mm/page_vma_mapped.c:check_pte() will fail to identify a PFN match as swp_offset_pfn() wrongly masks off PFN bits. For example, split_huge_page_to_list()->...->remap_page() will leave migration entries in place and continue to unlock the page. Later, when we stumble over these migration entries (e.g., via /proc/self/pagemap), pfn_swap_entry_to_page() will BUG_ON() because these migration entries shouldn't exist anymore and the page was unlocked. [ 33.067591] kernel BUG at include/linux/swapops.h:497! [ 33.067597] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI [ 33.067602] CPU: 3 PID: 742 Comm: cow Tainted: G E 6.1.0-rc8+ #16 [ 33.067605] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.fc36 04/01/2014 [ 33.067606] EIP: pagemap_pmd_range+0x644/0x650 [ 33.067612] Code: 00 00 00 00 66 90 89 ce b9 00 f0 ff ff e9 ff fb ff ff 89 d8 31 db e8 48 c6 52 00 e9 23 fb ff ff e8 61 83 56 00 e9 b6 fe ff ff <0f> 0b bf 00 f0 ff ff e9 38 fa ff ff 3e 8d 74 26 00 55 89 e5 57 31 [ 33.067615] EAX: ee394000 EBX: 00000002 ECX: ee394000 EDX: 00000000 [ 33.067617] ESI: c1b0ded4 EDI: 00024a00 EBP: c1b0ddb4 ESP: c1b0dd68 [ 33.067619] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00010246 [ 33.067624] CR0: 80050033 CR2: b7a00000 CR3: 01bbbd20 CR4: 00350ef0 [ 33.067625] Call Trace: [ 33.067628] ? madvise_free_pte_range+0x720/0x720 [ 33.067632] ? smaps_pte_range+0x4b0/0x4b0 [ 33.067634] walk_pgd_range+0x325/0x720 [ 33.067637] ? mt_find+0x1d6/0x3a0 [ 33.067641] ? mt_find+0x1d6/0x3a0 [ 33.067643] __walk_page_range+0x164/0x170 [ 33.067646] walk_page_range+0xf9/0x170 [ 33.067648] ? __kmem_cache_alloc_node+0x2a8/0x340 [ 33.067653] pagemap_read+0x124/0x280 [ 33.067658] ? default_llseek+0x101/0x160 [ 33.067662] ? smaps_account+0x1d0/0x1d0 [ 33.067664] vfs_read+0x90/0x290 [ 33.067667] ? do_madvise.part.0+0x24b/0x390 [ 33.067669] ? debug_smp_processor_id+0x12/0x20 [ 33.067673] ksys_pread64+0x58/0x90 [ 33.067675] __ia32_sys_ia32_pread64+0x1b/0x20 [ 33.067680] __do_fast_syscall_32+0x4c/0xc0 [ 33.067683] do_fast_syscall_32+0x29/0x60 [ 33.067686] do_SYSENTER_32+0x15/0x20 [ 33.067689] entry_SYSENTER_32+0x98/0xf1 Decrease the indentation level of SWP_PFN_BITS and SWP_PFN_MASK to keep it readable and consistent. [david@redhat.com: rely on sizeof(phys_addr_t) and min_t() instead] Link: https://lkml.kernel.org/r/20221206105737.69478-1-david@redhat.com [david@redhat.com: use "int" for comparison, as we're only comparing numbers < 64] Link: https://lkml.kernel.org/r/1f157500-2676-7cef-a84e-9224ed64e540@redhat.com Link: https://lkml.kernel.org/r/20221205150857.167583-1-david@redhat.com Fixes: 0d206b5d2e0d ("mm/swap: add swp_offset_pfn() to fetch PFN from swap entry") Signed-off-by: David Hildenbrand Acked-by: Peter Xu Reviewed-by: Yang Shi Cc: Hugh Dickins Cc: Andrea Arcangeli Signed-off-by: Andrew Morton --- include/linux/swapops.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/include/linux/swapops.h b/include/linux/swapops.h index 86b95ccb81bb..b07b277d6a16 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -33,11 +33,13 @@ * can use the extra bits to store other information besides PFN. */ #ifdef MAX_PHYSMEM_BITS -#define SWP_PFN_BITS (MAX_PHYSMEM_BITS - PAGE_SHIFT) +#define SWP_PFN_BITS (MAX_PHYSMEM_BITS - PAGE_SHIFT) #else /* MAX_PHYSMEM_BITS */ -#define SWP_PFN_BITS (BITS_PER_LONG - PAGE_SHIFT) +#define SWP_PFN_BITS min_t(int, \ + sizeof(phys_addr_t) * 8 - PAGE_SHIFT, \ + SWP_TYPE_SHIFT) #endif /* MAX_PHYSMEM_BITS */ -#define SWP_PFN_MASK (BIT(SWP_PFN_BITS) - 1) +#define SWP_PFN_MASK (BIT(SWP_PFN_BITS) - 1) /** * Migration swap entry specific bitfield definitions. Layout: From 6c28ca6485ddd7c5da171e479e3ebfbe661efc4d Mon Sep 17 00:00:00 2001 From: Liam Howlett Date: Mon, 5 Dec 2022 19:23:17 +0000 Subject: [PATCH 6/9] mmap: fix do_brk_flags() modifying obviously incorrect VMAs Add more sanity checks to the VMA that do_brk_flags() will expand. Ensure the VMA matches basic merge requirements within the function before calling can_vma_merge_after(). Drop the duplicate checks from vm_brk_flags() since they will be enforced later. The old code would expand file VMAs on brk(), which is functionally wrong and also dangerous in terms of locking because the brk() path isn't designed for file VMAs and therefore doesn't lock the file mapping. Checking can_vma_merge_after() ensures that new anonymous VMAs can't be merged into file VMAs. See https://lore.kernel.org/linux-mm/CAG48ez1tJZTOjS_FjRZhvtDA-STFmdw8PEizPDwMGFd_ui0Nrw@mail.gmail.com/ Link: https://lkml.kernel.org/r/20221205192304.1957418-1-Liam.Howlett@oracle.com Fixes: 2e7ce7d354f2 ("mm/mmap: change do_brk_flags() to expand existing VMA and add do_brk_munmap()") Signed-off-by: Liam R. Howlett Suggested-by: Jann Horn Cc: Jason A. Donenfeld Cc: Matthew Wilcox Cc: SeongJae Park Cc: Vlastimil Babka Cc: Yu Zhao Signed-off-by: Andrew Morton --- mm/mmap.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 0024e615d069..1d9aac3aa899 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2948,9 +2948,9 @@ static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma, * Expand the existing vma if possible; Note that singular lists do not * occur after forking, so the expand will only happen on new VMAs. */ - if (vma && - (!vma->anon_vma || list_is_singular(&vma->anon_vma_chain)) && - ((vma->vm_flags & ~VM_SOFTDIRTY) == flags)) { + if (vma && vma->vm_end == addr && !vma_policy(vma) && + can_vma_merge_after(vma, flags, NULL, NULL, + addr >> PAGE_SHIFT, NULL_VM_UFFD_CTX, NULL)) { mas_set_range(mas, vma->vm_start, addr + len - 1); if (mas_preallocate(mas, vma, GFP_KERNEL)) return -ENOMEM; @@ -3037,11 +3037,6 @@ int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags) goto munmap_failed; vma = mas_prev(&mas, 0); - if (!vma || vma->vm_end != addr || vma_policy(vma) || - !can_vma_merge_after(vma, flags, NULL, NULL, - addr >> PAGE_SHIFT, NULL_VM_UFFD_CTX, NULL)) - vma = NULL; - ret = do_brk_flags(&mas, vma, addr, len, flags); populate = ((mm->def_flags & VM_LOCKED) != 0); mmap_write_unlock(mm); From fcd0ccd836ffad73d98a66f6fea7b16f735ea920 Mon Sep 17 00:00:00 2001 From: John Starks Date: Tue, 6 Dec 2022 22:00:53 -0800 Subject: [PATCH 7/9] mm/gup: fix gup_pud_range() for dax For dax pud, pud_huge() returns true on x86. So the function works as long as hugetlb is configured. However, dax doesn't depend on hugetlb. Commit 414fd080d125 ("mm/gup: fix gup_pmd_range() for dax") fixed devmap-backed huge PMDs, but missed devmap-backed huge PUDs. Fix this as well. This fixes the below kernel panic: general protection fault, probably for non-canonical address 0x69e7c000cc478: 0000 [#1] SMP < snip > Call Trace: get_user_pages_fast+0x1f/0x40 iov_iter_get_pages+0xc6/0x3b0 ? mempool_alloc+0x5d/0x170 bio_iov_iter_get_pages+0x82/0x4e0 ? bvec_alloc+0x91/0xc0 ? bio_alloc_bioset+0x19a/0x2a0 blkdev_direct_IO+0x282/0x480 ? __io_complete_rw_common+0xc0/0xc0 ? filemap_range_has_page+0x82/0xc0 generic_file_direct_write+0x9d/0x1a0 ? inode_update_time+0x24/0x30 __generic_file_write_iter+0xbd/0x1e0 blkdev_write_iter+0xb4/0x150 ? io_import_iovec+0x8d/0x340 io_write+0xf9/0x300 io_issue_sqe+0x3c3/0x1d30 ? sysvec_reschedule_ipi+0x6c/0x80 __io_queue_sqe+0x33/0x240 ? fget+0x76/0xa0 io_submit_sqes+0xe6a/0x18d0 ? __fget_light+0xd1/0x100 __x64_sys_io_uring_enter+0x199/0x880 ? __context_tracking_enter+0x1f/0x70 ? irqentry_exit_to_user_mode+0x24/0x30 ? irqentry_exit+0x1d/0x30 ? __context_tracking_exit+0xe/0x70 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fc97c11a7be < snip > ---[ end trace 48b2e0e67debcaeb ]--- RIP: 0010:internal_get_user_pages_fast+0x340/0x990 < snip > Kernel panic - not syncing: Fatal exception Kernel Offset: disabled Link: https://lkml.kernel.org/r/1670392853-28252-1-git-send-email-ssengar@linux.microsoft.com Fixes: 414fd080d125 ("mm/gup: fix gup_pmd_range() for dax") Signed-off-by: John Starks Signed-off-by: Saurabh Sengar Cc: Jan Kara Cc: Yu Zhao Cc: Jason Gunthorpe Cc: John Hubbard Cc: David Hildenbrand Cc: Dan Williams Cc: Alistair Popple Cc: Signed-off-by: Andrew Morton --- mm/gup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/gup.c b/mm/gup.c index fe195d47de74..3b7bc2c1fd44 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2852,7 +2852,7 @@ static int gup_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr, unsigned lo next = pud_addr_end(addr, end); if (unlikely(!pud_present(pud))) return 0; - if (unlikely(pud_huge(pud))) { + if (unlikely(pud_huge(pud) || pud_devmap(pud))) { if (!gup_huge_pud(pud, pudp, addr, next, flags, pages, nr)) return 0; From a501788ab2603d97c41e8cda59cd74b72c29951f Mon Sep 17 00:00:00 2001 From: Muchun Song Date: Thu, 8 Dec 2022 19:55:48 +0800 Subject: [PATCH 8/9] MAINTAINERS: update Muchun Song's email I'm moving to the @linux.dev account. Map my old addresses and update it to my new address. Link: https://lkml.kernel.org/r/20221208115548.85244-1-songmuchun@bytedance.com Signed-off-by: Muchun Song Signed-off-by: Andrew Morton --- .mailmap | 2 ++ MAINTAINERS | 4 ++-- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/.mailmap b/.mailmap index 315e2207439a..f5bd014469d7 100644 --- a/.mailmap +++ b/.mailmap @@ -373,6 +373,8 @@ Ricardo Ribalda Roman Gushchin Roman Gushchin Roman Gushchin +Muchun Song +Muchun Song Ross Zwisler Rudolf Marek Rui Saraiva diff --git a/MAINTAINERS b/MAINTAINERS index 0e152a7afda8..93913c3825a8 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5299,7 +5299,7 @@ M: Johannes Weiner M: Michal Hocko M: Roman Gushchin M: Shakeel Butt -R: Muchun Song +R: Muchun Song L: cgroups@vger.kernel.org L: linux-mm@kvack.org S: Maintained @@ -9443,7 +9443,7 @@ F: drivers/net/ethernet/huawei/hinic/ HUGETLB SUBSYSTEM M: Mike Kravetz -M: Muchun Song +M: Muchun Song L: linux-mm@kvack.org S: Maintained F: Documentation/ABI/testing/sysfs-kernel-mm-hugepages From 4a7ba45b1a435e7097ca0f79a847d0949d0eb088 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 7 Dec 2022 16:53:15 -1000 Subject: [PATCH 9/9] memcg: fix possible use-after-free in memcg_write_event_control() memcg_write_event_control() accesses the dentry->d_name of the specified control fd to route the write call. As a cgroup interface file can't be renamed, it's safe to access d_name as long as the specified file is a regular cgroup file. Also, as these cgroup interface files can't be removed before the directory, it's safe to access the parent too. Prior to 347c4a874710 ("memcg: remove cgroup_event->cft"), there was a call to __file_cft() which verified that the specified file is a regular cgroupfs file before further accesses. The cftype pointer returned from __file_cft() was no longer necessary and the commit inadvertently dropped the file type check with it allowing any file to slip through. With the invarients broken, the d_name and parent accesses can now race against renames and removals of arbitrary files and cause use-after-free's. Fix the bug by resurrecting the file type check in __file_cft(). Now that cgroupfs is implemented through kernfs, checking the file operations needs to go through a layer of indirection. Instead, let's check the superblock and dentry type. Link: https://lkml.kernel.org/r/Y5FRm/cfcKPGzWwl@slm.duckdns.org Fixes: 347c4a874710 ("memcg: remove cgroup_event->cft") Signed-off-by: Tejun Heo Reported-by: Jann Horn Acked-by: Roman Gushchin Acked-by: Johannes Weiner Cc: Linus Torvalds Cc: Michal Hocko Cc: Muchun Song Cc: Shakeel Butt Cc: [3.14+] Signed-off-by: Andrew Morton --- include/linux/cgroup.h | 1 + kernel/cgroup/cgroup-internal.h | 1 - mm/memcontrol.c | 15 +++++++++++++-- 3 files changed, 14 insertions(+), 3 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 528bd44b59e2..2b7d077de7ef 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -68,6 +68,7 @@ struct css_task_iter { struct list_head iters_node; /* css_set->task_iters */ }; +extern struct file_system_type cgroup_fs_type; extern struct cgroup_root cgrp_dfl_root; extern struct css_set init_css_set; diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h index fd4020835ec6..367b0a42ada9 100644 --- a/kernel/cgroup/cgroup-internal.h +++ b/kernel/cgroup/cgroup-internal.h @@ -167,7 +167,6 @@ struct cgroup_mgctx { extern spinlock_t css_set_lock; extern struct cgroup_subsys *cgroup_subsys[]; extern struct list_head cgroup_roots; -extern struct file_system_type cgroup_fs_type; /* iterate across the hierarchies */ #define for_each_root(root) \ diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a1a35c12635e..266a1ab05434 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4832,6 +4832,7 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, unsigned int efd, cfd; struct fd efile; struct fd cfile; + struct dentry *cdentry; const char *name; char *endp; int ret; @@ -4885,6 +4886,16 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, if (ret < 0) goto out_put_cfile; + /* + * The control file must be a regular cgroup1 file. As a regular cgroup + * file can't be renamed, it's safe to access its name afterwards. + */ + cdentry = cfile.file->f_path.dentry; + if (cdentry->d_sb->s_type != &cgroup_fs_type || !d_is_reg(cdentry)) { + ret = -EINVAL; + goto out_put_cfile; + } + /* * Determine the event callbacks and set them in @event. This used * to be done via struct cftype but cgroup core no longer knows @@ -4893,7 +4904,7 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, * * DO NOT ADD NEW FILES. */ - name = cfile.file->f_path.dentry->d_name.name; + name = cdentry->d_name.name; if (!strcmp(name, "memory.usage_in_bytes")) { event->register_event = mem_cgroup_usage_register_event; @@ -4917,7 +4928,7 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, * automatically removed on cgroup destruction but the removal is * asynchronous, so take an extra ref on @css. */ - cfile_css = css_tryget_online_from_dir(cfile.file->f_path.dentry->d_parent, + cfile_css = css_tryget_online_from_dir(cdentry->d_parent, &memory_cgrp_subsys); ret = -EINVAL; if (IS_ERR(cfile_css))