[moderation] [fs?] KCSAN: data-race in filemap_read / filemap_read (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1e1ba8d23dae Merge tag 'timers-clocksource-2025-03-26' of ..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=155aabb0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6b81011ebe099f
dashboard link: https://syzkaller.appspot.com/bug?extid=d19a771491d23a5abd3a
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/d3d2f9cf0f25/disk-1e1ba8d2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/aae63ca7d829/vmlinux-1e1ba8d2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d3fc3d1112f0/bzImage-1e1ba8d2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d19a77...@syzkaller.appspotmail.com

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

read to 0xffff8881034b75e8 of 8 bytes by task 16625 on cpu 1:
filemap_read+0x85/0x8d0 mm/filemap.c:2675
generic_file_read_iter+0x78/0x330 mm/filemap.c:2893
ext4_file_read_iter+0x1cc/0x290 fs/ext4/file.c:-1
copy_splice_read+0x390/0x5d0 fs/splice.c:363
do_splice_read fs/splice.c:978 [inline]
splice_direct_to_actor+0x28e/0x680 fs/splice.c:1083
do_splice_direct_actor fs/splice.c:1201 [inline]
do_splice_direct+0xd9/0x150 fs/splice.c:1227
do_sendfile+0x40a/0x690 fs/read_write.c:1368
__do_sys_sendfile64 fs/read_write.c:1429 [inline]
__se_sys_sendfile64 fs/read_write.c:1415 [inline]
__x64_sys_sendfile64+0x113/0x160 fs/read_write.c:1415
x64_sys_call+0xfc3/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:41
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

write to 0xffff8881034b75e8 of 8 bytes by task 16630 on cpu 0:
filemap_read+0x842/0x8d0 mm/filemap.c:2774
generic_file_read_iter+0x78/0x330 mm/filemap.c:2893
ext4_file_read_iter+0x1cc/0x290 fs/ext4/file.c:-1
copy_splice_read+0x390/0x5d0 fs/splice.c:363
do_splice_read fs/splice.c:978 [inline]
splice_direct_to_actor+0x28e/0x680 fs/splice.c:1083
do_splice_direct_actor fs/splice.c:1201 [inline]
do_splice_direct+0xd9/0x150 fs/splice.c:1227
do_sendfile+0x40a/0x690 fs/read_write.c:1368
__do_sys_sendfile64 fs/read_write.c:1429 [inline]
__se_sys_sendfile64 fs/read_write.c:1415 [inline]
__x64_sys_sendfile64+0x113/0x160 fs/read_write.c:1415
x64_sys_call+0xfc3/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:41
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: 0x0000000000000323 -> 0x0000000000000324

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 16630 Comm: syz.5.4778 Not tainted 6.14.0-syzkaller-03576-g1e1ba8d23dae #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.