[moderation] [fs?] KCSAN: data-race in file_update_time / inode_update_timestamps (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0af2f6be1b42 Linux 6.15-rc1
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12384070580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e5bf3e2a48bfe768
dashboard link: https://syzkaller.appspot.com/bug?extid=2f7a9fb1b6766445675a
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/d90ae40aa6df/disk-0af2f6be.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/616ed7a70804/vmlinux-0af2f6be.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ed2c418afc9a/bzImage-0af2f6be.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2f7a9f...@syzkaller.appspotmail.com

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

write to 0xffff88811897c6c4 of 4 bytes by task 17627 on cpu 1:
inode_set_mtime_to_ts include/linux/fs.h:1706 [inline]
inode_update_timestamps+0x139/0x250 fs/inode.c:2022
generic_update_time fs/inode.c:2057 [inline]
inode_update_time fs/inode.c:2077 [inline]
__file_update_time fs/inode.c:2305 [inline]
file_update_time+0x219/0x2b0 fs/inode.c:2335
fault_dirty_shared_page+0xd7/0x3b0 mm/memory.c:3329
do_shared_fault mm/memory.c:5610 [inline]
do_fault mm/memory.c:5656 [inline]
do_pte_missing mm/memory.c:4160 [inline]
handle_pte_fault mm/memory.c:5997 [inline]
__handle_mm_fault mm/memory.c:6140 [inline]
handle_mm_fault+0x154c/0x2e80 mm/memory.c:6309
faultin_page mm/gup.c:1193 [inline]
__get_user_pages+0xf4e/0x2340 mm/gup.c:1491
__get_user_pages_locked mm/gup.c:1757 [inline]
faultin_page_range+0x352/0x5d0 mm/gup.c:1981
madvise_populate mm/madvise.c:965 [inline]
madvise_do_behavior+0x10e/0x2530 mm/madvise.c:1693
do_madvise mm/madvise.c:1782 [inline]
__do_sys_madvise mm/madvise.c:1790 [inline]
__se_sys_madvise mm/madvise.c:1788 [inline]
__x64_sys_madvise+0xcb/0x100 mm/madvise.c:1788
x64_sys_call+0x23b8/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:29
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811897c6c4 of 4 bytes by task 17628 on cpu 0:
inode_get_mtime_nsec include/linux/fs.h:1692 [inline]
inode_get_mtime include/linux/fs.h:1698 [inline]
inode_needs_update_time fs/inode.c:2284 [inline]
file_update_time+0x8b/0x2b0 fs/inode.c:2331
fault_dirty_shared_page+0xd7/0x3b0 mm/memory.c:3329
do_shared_fault mm/memory.c:5610 [inline]
do_fault mm/memory.c:5656 [inline]
do_pte_missing mm/memory.c:4160 [inline]
handle_pte_fault mm/memory.c:5997 [inline]
__handle_mm_fault mm/memory.c:6140 [inline]
handle_mm_fault+0x154c/0x2e80 mm/memory.c:6309
faultin_page mm/gup.c:1193 [inline]
__get_user_pages+0xf4e/0x2340 mm/gup.c:1491
__get_user_pages_locked mm/gup.c:1757 [inline]
faultin_page_range+0x352/0x5d0 mm/gup.c:1981
madvise_populate mm/madvise.c:965 [inline]
madvise_do_behavior+0x10e/0x2530 mm/madvise.c:1693
do_madvise mm/madvise.c:1782 [inline]
__do_sys_madvise mm/madvise.c:1790 [inline]
__se_sys_madvise mm/madvise.c:1788 [inline]
__x64_sys_madvise+0xcb/0x100 mm/madvise.c:1788
x64_sys_call+0x23b8/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:29
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x236256a9 -> 0x23faed29

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 17628 Comm: syz.3.4930 Not tainted 6.15.0-rc1-syzkaller #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================


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[syzbot]

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