[moderation] [exfat?] KCSAN: data-race in _copy_to_iter / fat_set_state (7)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 610a9b8f49fb Linux 6.7-rc8
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=150dd291e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=17e138c8fc533c5e
dashboard link: https://syzkaller.appspot.com/bug?extid=33d3a155fe2eb4624356
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [hiro...@mail.parknet.co.jp linki...@kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org sj155...@samsung.com]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/238dea1fdecf/disk-610a9b8f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c4adb81883c3/vmlinux-610a9b8f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ad74642e2389/bzImage-610a9b8f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+33d3a1...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in _copy_to_iter / fat_set_state

write to 0xffff888149081025 of 1 bytes by task 12041 on cpu 1:
fat_set_state+0x16e/0x1d0
fat_put_super+0x2e/0x80 fs/fat/inode.c:737
generic_shutdown_super+0xdb/0x210 fs/super.c:696
kill_block_super+0x2a/0x60 fs/super.c:1667
deactivate_locked_super+0x7a/0x1c0 fs/super.c:484
deactivate_super+0x9b/0xb0 fs/super.c:517
cleanup_mnt+0x272/0x2e0 fs/namespace.c:1256
__cleanup_mnt+0x19/0x20 fs/namespace.c:1263
task_work_run+0x135/0x1a0 kernel/task_work.c:180
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xd6/0xe0 kernel/entry/common.c:171
exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:296
do_syscall_64+0x50/0x110 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888149081000 of 1024 bytes by task 12046 on cpu 0:
instrument_copy_to_user include/linux/instrumented.h:113 [inline]
copy_to_user_iter lib/iov_iter.c:24 [inline]
iterate_ubuf include/linux/iov_iter.h:29 [inline]
iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
iterate_and_advance include/linux/iov_iter.h:271 [inline]
_copy_to_iter+0x126/0xb20 lib/iov_iter.c:186
copy_page_to_iter+0x171/0x2b0 lib/iov_iter.c:381
copy_folio_to_iter include/linux/uio.h:181 [inline]
filemap_read+0x42c/0x680 mm/filemap.c:2653
blkdev_read_iter+0x217/0x2c0 block/fops.c:742
call_read_iter include/linux/fs.h:2014 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x3c0/0x590 fs/read_write.c:470
ksys_read+0xeb/0x1a0 fs/read_write.c:613
__do_sys_read fs/read_write.c:623 [inline]
__se_sys_read fs/read_write.c:621 [inline]
__x64_sys_read+0x42/0x50 fs/read_write.c:621
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 12046 Comm: udevd Not tainted 6.7.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
I/O error, dev loop0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
I/O error, dev loop0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2
Buffer I/O error on dev loop0, logical block 0, async page read
I/O error, dev loop0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
I/O error, dev loop0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2
Buffer I/O error on dev loop0, logical block 0, async page read
I/O error, dev loop4, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2


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[syzbot]

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