KCSAN: data-race in generic_file_buffered_read / set_blocksize

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: aae5ab85 Merge tag 'riscv-for-linus-5.10-rc6' of git://git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1685b32d500000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9b19d1bde60f8d
dashboard link: https://syzkaller.appspot.com/bug?extid=0eb93ed1001ce784b24a
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+0eb93e...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in generic_file_buffered_read / set_blocksize

write to 0xffff88810be69c06 of 1 bytes by task 3069 on cpu 0:
set_blocksize+0x21f/0x2b0 fs/block_dev.c:153
sb_set_blocksize+0x2c/0xa0 fs/block_dev.c:163
udf_load_vrs+0x61/0x630 fs/udf/super.c:1967
udf_fill_super+0x4d4/0xd50 fs/udf/super.c:2186
mount_bdev+0x1e2/0x280 fs/super.c:1419
udf_mount+0x2d/0x40 fs/udf/super.c:127
legacy_get_tree+0x70/0xc0 fs/fs_context.c:592
vfs_get_tree+0x4a/0x190 fs/super.c:1549
do_new_mount fs/namespace.c:2875 [inline]
path_mount+0x119d/0x1c10 fs/namespace.c:3205
do_mount fs/namespace.c:3218 [inline]
__do_sys_mount fs/namespace.c:3426 [inline]
__se_sys_mount+0x23d/0x2e0 fs/namespace.c:3403
__x64_sys_mount+0x63/0x70 fs/namespace.c:3403
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810be69c06 of 1 bytes by task 1962 on cpu 1:
generic_file_buffered_read+0x6c0/0x23a0 mm/filemap.c:2276
generic_file_read_iter+0x80/0x3d0 mm/filemap.c:2553
blkdev_read_iter+0xb3/0xc0 fs/block_dev.c:1925
call_read_iter include/linux/fs.h:1897 [inline]
new_sync_read fs/read_write.c:415 [inline]
vfs_read+0x552/0x5c0 fs/read_write.c:496
ksys_read+0xce/0x180 fs/read_write.c:634
__do_sys_read fs/read_write.c:644 [inline]
__se_sys_read fs/read_write.c:642 [inline]
__x64_sys_read+0x3e/0x50 fs/read_write.c:642
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: 1962 Comm: systemd-udevd Not tainted 5.10.0-rc5-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.