[moderation] [mm?] KCSAN: data-race in next_uptodate_folio / shmem_write_end

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 5e3f5b81de80 Merge tag 'net-6.7-rc5' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17cb8c96e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=ac34c1f29a8029df
dashboard link: https://syzkaller.appspot.com/bug?extid=92075be90d0a2f5b0265
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org hu...@google.com linux-...@vger.kernel.org linu...@kvack.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8894c209e25f/disk-5e3f5b81.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/42757ce1a7da/vmlinux-5e3f5b81.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a3314e0b4681/bzImage-5e3f5b81.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+92075b...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in next_uptodate_folio / shmem_write_end

write to 0xffff888103a669f0 of 8 bytes by task 26735 on cpu 1:
i_size_write include/linux/fs.h:932 [inline]
shmem_write_end+0x9a/0x470 mm/shmem.c:2726
generic_perform_write+0x267/0x410 mm/filemap.c:3929
shmem_file_write_iter+0xc8/0xe0 mm/shmem.c:2878
call_write_iter include/linux/fs.h:2020 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x48a/0x790 fs/read_write.c:584
ksys_write+0xeb/0x1a0 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__x64_sys_write+0x42/0x50 fs/read_write.c:646
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888103a669f0 of 8 bytes by task 26740 on cpu 0:
i_size_read include/linux/fs.h:910 [inline]
next_uptodate_folio+0x5c9/0x7a0 mm/filemap.c:3408
filemap_map_pages+0x6e7/0x8d0 mm/filemap.c:3556
do_fault_around mm/memory.c:4586 [inline]
do_read_fault mm/memory.c:4619 [inline]
do_fault mm/memory.c:4762 [inline]
do_pte_missing mm/memory.c:3730 [inline]
handle_pte_fault mm/memory.c:5038 [inline]
__handle_mm_fault mm/memory.c:5179 [inline]
handle_mm_fault+0x1239/0x2dd0 mm/memory.c:5344
faultin_page mm/gup.c:956 [inline]
__get_user_pages+0x402/0xe40 mm/gup.c:1239
populate_vma_page_range mm/gup.c:1677 [inline]
__mm_populate+0x216/0x330 mm/gup.c:1786
mm_populate include/linux/mm.h:3379 [inline]
vm_mmap_pgoff+0x1a7/0x240 mm/util.c:561
ksys_mmap_pgoff+0x2b8/0x330 mm/mmap.c:1425
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000ce7000 -> 0x0000000000ce8000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 26740 Comm: syz-executor.1 Tainted: G W 6.7.0-rc4-syzkaller-00111-g5e3f5b81de80 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.