[moderation] [fs?] KCSAN: data-race in inode_set_ctime_current / inode_update_timestamps (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 5635f189425e Merge tag 'bpf-fixes' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16365340580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b957b77e265904d
dashboard link: https://syzkaller.appspot.com/bug?extid=c0720e600644b25b76fa
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [bra...@kernel.org ja...@suse.cz linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/02c8e8934f70/disk-5635f189.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0c7f87b1c9fb/vmlinux-5635f189.xz
kernel image: https://storage.googleapis.com/syzbot-assets/27052a026e2c/bzImage-5635f189.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c0720e...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in inode_set_ctime_current / inode_update_timestamps

write to 0xffff8881047d7b18 of 4 bytes by task 27687 on cpu 0:
inode_set_ctime_to_ts include/linux/fs.h:1678 [inline]
inode_set_ctime_current+0x35/0x50 fs/inode.c:2664
shmem_truncate_range+0x2f/0x70 mm/shmem.c:1145
shmem_setattr+0x791/0x830 mm/shmem.c:1229
notify_change+0x85c/0x8e0 fs/attr.c:503
do_truncate fs/open.c:65 [inline]
do_ftruncate+0x3cf/0x460 fs/open.c:181
do_sys_ftruncate fs/open.c:199 [inline]
__do_sys_ftruncate fs/open.c:207 [inline]
__se_sys_ftruncate fs/open.c:205 [inline]
__x64_sys_ftruncate+0x6a/0xc0 fs/open.c:205
x64_sys_call+0x8e5/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:78
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881047d7b18 of 4 bytes by task 27678 on cpu 1:
inode_get_ctime_nsec include/linux/fs.h:1663 [inline]
inode_get_ctime include/linux/fs.h:1669 [inline]
inode_update_timestamps+0x56/0x280 fs/inode.c:1994
generic_update_time fs/inode.c:2036 [inline]
inode_update_time fs/inode.c:2056 [inline]
__file_update_time fs/inode.c:2245 [inline]
file_update_time+0x220/0x2b0 fs/inode.c:2275
fault_dirty_shared_page+0xde/0x340 mm/memory.c:3204
do_shared_fault mm/memory.c:5389 [inline]
do_fault mm/memory.c:5435 [inline]
do_pte_missing mm/memory.c:3965 [inline]
handle_pte_fault mm/memory.c:5766 [inline]
__handle_mm_fault mm/memory.c:5909 [inline]
handle_mm_fault+0x1370/0x2a80 mm/memory.c:6077
do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x3b9/0x650 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0x25e79932 -> 0x35ff78b7

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 27678 Comm: syz.0.4118 Not tainted 6.12.0-rc5-syzkaller-00176-g5635f189425e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================


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[syzbot]

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