KCSAN: data-race in __writeback_single_inode / ext4_set_iomap (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 111e91a6 Merge tag 's390-5.10-4' of git://git.kernel.org/p..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10622d72500000
kernel config: https://syzkaller.appspot.com/x/.config?x=e0bbcd06922dbd46
dashboard link: https://syzkaller.appspot.com/bug?extid=5418db9cb5a39107a050
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5418db...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __writeback_single_inode / ext4_set_iomap

read-write to 0xffff88810e786c58 of 8 bytes by task 20960 on cpu 0:
__writeback_single_inode+0x248/0x560 fs/fs-writeback.c:1492
writeback_single_inode+0x126/0x580 fs/fs-writeback.c:1570
sync_inode fs/fs-writeback.c:2606 [inline]
sync_inode_metadata+0x52/0x70 fs/fs-writeback.c:2626
ext4_fsync_nojournal fs/ext4/fsync.c:92 [inline]
ext4_sync_file+0x359/0x6c0 fs/ext4/fsync.c:170
vfs_fsync_range+0x107/0x120 fs/sync.c:200
generic_write_sync include/linux/fs.h:2739 [inline]
ext4_buffered_write_iter+0x384/0x3d0 fs/ext4/file.c:278
ext4_file_write_iter+0x45e/0x1090 fs/ext4/file.c:503
call_write_iter include/linux/fs.h:1903 [inline]
do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
do_iter_write+0x112/0x4b0 fs/read_write.c:866
vfs_iter_write+0x4c/0x70 fs/read_write.c:907
iter_file_splice_write+0x42a/0x780 fs/splice.c:686
do_splice_from fs/splice.c:764 [inline]
direct_splice_actor+0x80/0xa0 fs/splice.c:933
splice_direct_to_actor+0x345/0x650 fs/splice.c:888
do_splice_direct+0xf5/0x170 fs/splice.c:976
do_sendfile+0x5db/0xca0 fs/read_write.c:1257
__do_sys_sendfile64 fs/read_write.c:1312 [inline]
__se_sys_sendfile64 fs/read_write.c:1304 [inline]
__x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1304
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810e786c58 of 8 bytes by task 20957 on cpu 1:
ext4_inode_datasync_dirty fs/ext4/inode.c:3322 [inline]
ext4_set_iomap+0x182/0x440 fs/ext4/inode.c:3337
ext4_iomap_begin+0x641/0x690 fs/ext4/inode.c:3476
iomap_apply+0x8d/0x4a0 fs/iomap/apply.c:46
__iomap_dio_rw+0x448/0x9b0 fs/iomap/direct-io.c:517
iomap_dio_rw+0x30/0x70 fs/iomap/direct-io.c:605
ext4_dio_read_iter fs/ext4/file.c:77 [inline]
ext4_file_read_iter+0x3bd/0x420 fs/ext4/file.c:129
call_read_iter include/linux/fs.h:1897 [inline]
generic_file_splice_read+0x22a/0x310 fs/splice.c:311
do_splice_to fs/splice.c:788 [inline]
splice_direct_to_actor+0x2aa/0x650 fs/splice.c:867
do_splice_direct+0xf5/0x170 fs/splice.c:976
do_sendfile+0x5db/0xca0 fs/read_write.c:1257
__do_sys_sendfile64 fs/read_write.c:1318 [inline]
__se_sys_sendfile64 fs/read_write.c:1304 [inline]
__x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 20957 Comm: syz-executor.1 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[syzbot]

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