[moderation] [ext4?] KCSAN: data-race in touch_atime / touch_atime (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1613e604df0c Linux 6.10-rc1
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12355ca4980000
kernel config: https://syzkaller.appspot.com/x/.config?x=b639694183430f97
dashboard link: https://syzkaller.appspot.com/bug?extid=d339c673f459c1a220ea
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [adilger...@dilger.ca linux...@vger.kernel.org linux-...@vger.kernel.org ty...@mit.edu]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/515d9ab45ca5/disk-1613e604.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/94202de9ed1e/vmlinux-1613e604.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d2b7508a28df/bzImage-1613e604.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d339c6...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in touch_atime / touch_atime

write to 0xffff8881079a6608 of 8 bytes by task 15346 on cpu 1:
inode_set_atime_to_ts include/linux/fs.h:1557 [inline]
inode_update_timestamps fs/inode.c:1878 [inline]
generic_update_time fs/inode.c:1900 [inline]
inode_update_time fs/inode.c:1920 [inline]
touch_atime+0x1f3/0x350 fs/inode.c:1992
file_accessed include/linux/fs.h:2458 [inline]
filemap_splice_read+0x8b0/0x920 mm/filemap.c:2950
ext4_file_splice_read+0x95/0xc0 fs/ext4/file.c:158
do_splice_read fs/splice.c:985 [inline]
splice_direct_to_actor+0x26c/0x670 fs/splice.c:1089
do_splice_direct_actor fs/splice.c:1207 [inline]
do_splice_direct+0xd7/0x150 fs/splice.c:1233
do_sendfile+0x3ab/0x960 fs/read_write.c:1295
__do_sys_sendfile64 fs/read_write.c:1362 [inline]
__se_sys_sendfile64 fs/read_write.c:1348 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
x64_sys_call+0x2c9f/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:41
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 0xffff8881079a6608 of 8 bytes by task 15360 on cpu 0:
inode_get_atime include/linux/fs.h:1551 [inline]
inode_update_timestamps fs/inode.c:1875 [inline]
generic_update_time fs/inode.c:1900 [inline]
inode_update_time fs/inode.c:1920 [inline]
touch_atime+0x1a0/0x350 fs/inode.c:1992
file_accessed include/linux/fs.h:2458 [inline]
filemap_splice_read+0x8b0/0x920 mm/filemap.c:2950
ext4_file_splice_read+0x95/0xc0 fs/ext4/file.c:158
do_splice_read fs/splice.c:985 [inline]
splice_direct_to_actor+0x26c/0x670 fs/splice.c:1089
do_splice_direct_actor fs/splice.c:1207 [inline]
do_splice_direct+0xd7/0x150 fs/splice.c:1233
do_sendfile+0x3ab/0x960 fs/read_write.c:1295
__do_sys_sendfile64 fs/read_write.c:1362 [inline]
__se_sys_sendfile64 fs/read_write.c:1348 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
x64_sys_call+0x2c9f/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:41
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

value changed: 0x0000000025eee990 -> 0x0000000026878010

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15360 Comm: syz-executor.3 Not tainted 6.10.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
==================================================================


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