[moderation] [fs?] KCSAN: data-race in filemap_read / filemap_read (6)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8c6bc74c7f89 Merge tag 'v6.16-rc1-smb3-client-fixes' of gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=128b2e82580000
kernel config: https://syzkaller.appspot.com/x/.config?x=75ba7d6bc4eb7c9d
dashboard link: https://syzkaller.appspot.com/bug?extid=5de889f7f7e25c4e6d5a
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
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/8bb8ff23b86b/disk-8c6bc74c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b8ce1c10350a/vmlinux-8c6bc74c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/eff1a0604096/bzImage-8c6bc74c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5de889...@syzkaller.appspotmail.com

EXT4-fs: Ignoring removed orlov option
==================================================================
BUG: KCSAN: data-race in filemap_read / filemap_read

write to 0xffff88811227bfa8 of 8 bytes by task 7360 on cpu 1:
filemap_read+0x974/0xa00 mm/filemap.c:2784
generic_file_read_iter+0x79/0x330 mm/filemap.c:2903
ext4_file_read_iter+0x1cc/0x290 fs/ext4/file.c:-1
copy_splice_read+0x3c4/0x5f0 fs/splice.c:363
do_splice_read fs/splice.c:978 [inline]
splice_direct_to_actor+0x290/0x680 fs/splice.c:1083
do_splice_direct_actor fs/splice.c:1201 [inline]
do_splice_direct+0xda/0x150 fs/splice.c:1227
do_sendfile+0x380/0x650 fs/read_write.c:1370
__do_sys_sendfile64 fs/read_write.c:1431 [inline]
__se_sys_sendfile64 fs/read_write.c:1417 [inline]
__x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
x64_sys_call+0xb39/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811227bfa8 of 8 bytes by task 7354 on cpu 0:
filemap_read+0x6f/0xa00 mm/filemap.c:2685
generic_file_read_iter+0x79/0x330 mm/filemap.c:2903
ext4_file_read_iter+0x1cc/0x290 fs/ext4/file.c:-1
copy_splice_read+0x3c4/0x5f0 fs/splice.c:363
do_splice_read fs/splice.c:978 [inline]
splice_direct_to_actor+0x290/0x680 fs/splice.c:1083
do_splice_direct_actor fs/splice.c:1201 [inline]
do_splice_direct+0xda/0x150 fs/splice.c:1227
do_sendfile+0x380/0x650 fs/read_write.c:1370
__do_sys_sendfile64 fs/read_write.c:1431 [inline]
__se_sys_sendfile64 fs/read_write.c:1417 [inline]
__x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
x64_sys_call+0xb39/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000000000022d -> 0x000000000000022e

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 7354 Comm: syz.7.1178 Not tainted 6.16.0-rc1-syzkaller-00236-g8c6bc74c7f89 #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================


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