[moderation] [exfat?] KCSAN: data-race in generic_write_end / next_uptodate_folio (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f5837722ffec Merge tag 'mm-hotfixes-stable-2023-12-27-15-0..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12f63e09e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=4da1e2da456c3a7d
dashboard link: https://syzkaller.appspot.com/bug?extid=6a2ae6f4dc618966c004
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [hiro...@mail.parknet.co.jp linki...@kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org sj155...@samsung.com]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6aff0083d0f1/disk-f5837722.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7a95407790bc/vmlinux-f5837722.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1f0bdee701ad/bzImage-f5837722.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6a2ae6...@syzkaller.appspotmail.com

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

write to 0xffff8881063b7a80 of 8 bytes by task 32758 on cpu 1:
i_size_write include/linux/fs.h:932 [inline]
generic_write_end+0x94/0x230 fs/buffer.c:2291
fat_write_end+0x4e/0x160 fs/fat/inode.c:244
cont_expand_zero fs/buffer.c:2514 [inline]
cont_write_begin+0x2c0/0x690 fs/buffer.c:2572
fat_write_begin+0x61/0xf0 fs/fat/inode.c:230
generic_cont_expand_simple+0xa7/0x140 fs/buffer.c:2473
fat_cont_expand+0x3a/0x160 fs/fat/file.c:223
fat_setattr+0x2a9/0x840 fs/fat/file.c:513
notify_change+0x866/0x8e0 fs/attr.c:499
do_truncate+0x116/0x150 fs/open.c:66
do_sys_ftruncate+0x2ba/0x3b0 fs/open.c:194
__do_sys_ftruncate fs/open.c:205 [inline]
__se_sys_ftruncate fs/open.c:203 [inline]
__x64_sys_ftruncate+0x33/0x40 fs/open.c:203
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 0xffff8881063b7a80 of 8 bytes by task 32759 on cpu 0:
i_size_read include/linux/fs.h:910 [inline]
next_uptodate_folio+0x5c9/0x7a0 mm/filemap.c:3417
filemap_map_pages+0x708/0x900 mm/filemap.c:3565
do_fault_around mm/memory.c:4587 [inline]
do_read_fault mm/memory.c:4620 [inline]
do_fault mm/memory.c:4763 [inline]
do_pte_missing mm/memory.c:3731 [inline]
handle_pte_fault mm/memory.c:5039 [inline]
__handle_mm_fault mm/memory.c:5180 [inline]
handle_mm_fault+0x1239/0x2dd0 mm/memory.c:5345
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: 0x000000000055f000 -> 0x0000000000561000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 32759 Comm: syz-executor.3 Not tainted 6.7.0-rc7-syzkaller-00016-gf5837722ffec #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================


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[syzbot]

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