[moderation] [ext4?] KCSAN: data-race in file_modified_flags / inode_update_timestamps

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 2bfcfd584ff5 Merge tag 'pmdomain-v6.10-rc1' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16e3f744980000
kernel config: https://syzkaller.appspot.com/x/.config?x=b639694183430f97
dashboard link: https://syzkaller.appspot.com/bug?extid=1d111dbd571bc392f537
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/f2bd5cba5755/disk-2bfcfd58.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/10a3376907f7/vmlinux-2bfcfd58.xz
kernel image: https://storage.googleapis.com/syzbot-assets/29e81e0ad2a0/bzImage-2bfcfd58.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1d111d...@syzkaller.appspotmail.com

bridge2: the hash_elasticity option has been deprecated and is always 16
Cannot find add_set index 0 as target
==================================================================
BUG: KCSAN: data-race in file_modified_flags / inode_update_timestamps

write to 0xffff888120230f48 of 8 bytes by task 21362 on cpu 1:
inode_set_mtime_to_ts include/linux/fs.h:1587 [inline]
inode_update_timestamps+0x16f/0x280 fs/inode.c:1865
generic_update_time fs/inode.c:1900 [inline]
inode_update_time fs/inode.c:1920 [inline]
__file_update_time fs/inode.c:2109 [inline]
file_modified_flags+0x2a7/0x340 fs/inode.c:2180
file_modified+0x17/0x20 fs/inode.c:2196
ext4_dio_write_checks fs/ext4/file.c:485 [inline]
ext4_dio_write_iter fs/ext4/file.c:551 [inline]
ext4_file_write_iter+0x8b8/0xe30 fs/ext4/file.c:696
iter_file_splice_write+0x5e6/0x970 fs/splice.c:743
do_splice_from fs/splice.c:941 [inline]
direct_splice_actor+0x16c/0x2c0 fs/splice.c:1164
splice_direct_to_actor+0x305/0x670 fs/splice.c:1108
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 0xffff888120230f48 of 8 bytes by task 21358 on cpu 0:
inode_get_mtime include/linux/fs.h:1581 [inline]
inode_needs_update_time fs/inode.c:2088 [inline]
file_modified_flags+0xe6/0x340 fs/inode.c:2174
file_modified+0x17/0x20 fs/inode.c:2196
ext4_dio_write_checks fs/ext4/file.c:485 [inline]
ext4_dio_write_iter fs/ext4/file.c:551 [inline]
ext4_file_write_iter+0x8b8/0xe30 fs/ext4/file.c:696
iter_file_splice_write+0x5e6/0x970 fs/splice.c:743
do_splice_from fs/splice.c:941 [inline]
direct_splice_actor+0x16c/0x2c0 fs/splice.c:1164
splice_direct_to_actor+0x305/0x670 fs/splice.c:1108
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: 0x0000000020947fee -> 0x00000000225e436e

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 21358 Comm: syz-executor.3 Tainted: G W 6.10.0-rc1-syzkaller-00013-g2bfcfd584ff5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
==================================================================


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