INFO: task hung in filename_create (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=101748bb080000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=3c611218ee0d0789ecf7
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

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+3c6112...@syzkaller.appspotmail.com

loop2: rw=0, want=2052, limit=1119
attempt to access beyond end of device
loop2: rw=0, want=2054, limit=1119
attempt to access beyond end of device
loop2: rw=0, want=2056, limit=1119
INFO: task syz-executor.4:3080 blocked for more than 140 seconds.
Not tainted 4.19.211-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4 D27912 3080 25535 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2828 [inline]
__schedule+0x887/0x2040 kernel/sched/core.c:3517
schedule+0x8d/0x1b0 kernel/sched/core.c:3561
__rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline]
rwsem_down_write_failed+0x3aa/0x760 kernel/locking/rwsem-xadd.c:618
call_rwsem_down_write_failed+0x13/0x20 arch/x86/lib/rwsem.S:117
__down_write arch/x86/include/asm/rwsem.h:142 [inline]
down_write_nested+0x51/0x90 kernel/locking/rwsem.c:194
inode_lock_nested include/linux/fs.h:783 [inline]
filename_create+0x15a/0x490 fs/namei.c:3638
user_path_create fs/namei.c:3696 [inline]
do_mkdirat+0xa0/0x2d0 fs/namei.c:3834
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7ff1b1f0d3c9
Code: Bad RIP value.
RSP: 002b:00007ff1b0861168 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007ff1b2020050 RCX: 00007ff1b1f0d3c9
RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000006
RBP: 00007ff1b1f6833f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcbda2d61f R14: 00007ff1b0861300 R15: 0000000000022000

Showing all locks held in the system:
2 locks held by kworker/u4:2/61:
3 locks held by kworker/u4:5/1080:
1 lock held by khungtaskd/1572:
#0: 00000000f0f14bb5 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
1 lock held by in:imklog/7812:
#0: 000000000ed56ef2 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767
2 locks held by login/25537:
#0: 000000008e23eb25 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
#1: 0000000095bb89d2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1950 drivers/tty/n_tty.c:2154
3 locks held by kworker/u4:6/19088:
2 locks held by syz-executor.4/3079:
2 locks held by syz-executor.4/3080:
#0: 0000000049e8ff07 (sb_writers#26){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline]
#0: 0000000049e8ff07 (sb_writers#26){.+.+}, at: mnt_want_write+0x3a/0xb0 fs/namespace.c:360
#1: 00000000b6d39bc2 (&type->i_mutex_dir_key#12/1){+.+.}, at: inode_lock_nested include/linux/fs.h:783 [inline]
#1: 00000000b6d39bc2 (&type->i_mutex_dir_key#12/1){+.+.}, at: filename_create+0x15a/0x490 fs/namei.c:3638
1 lock held by syz-executor.2/14075:

=============================================

wlan1: No active IBSS STAs - trying to scan for other IBSS networks with same SSID (merge)
NMI backtrace for cpu 1
CPU: 1 PID: 1572 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
watchdog+0x991/0xe60 kernel/hung_task.c:287
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 19088 Comm: kworker/u4:6 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
Workqueue: bat_events batadv_purge_orig
RIP: 0010:lockdep_hardirqs_on+0x66/0x5c0 kernel/locking/lockdep.c:2849
Code: 84 57 03 00 00 65 48 8b 1c 25 c0 df 01 00 48 8d bb 84 08 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 <48> 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 c1 03 00 00 44
RSP: 0018:ffff888225d27bf0 EFLAGS: 00000803
RAX: dffffc0000000000 RBX: ffff88821a842240 RCX: 1ffffffff148be2c
RDX: 0000000000000000 RSI: ffffffff8167a995 RDI: ffff88821a842ac4
RBP: ffffffff813922a9 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: ffff88821a842240
R13: ffff88802e891200 R14: dffffc0000000000 R15: 000000000000012f
FS: 0000000000000000(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f184bed8000 CR3: 00000000b2915000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__local_bh_enable_ip+0x159/0x270 kernel/softirq.c:194
spin_unlock_bh include/linux/spinlock.h:374 [inline]
batadv_purge_orig_ref+0xa2c/0x1110 net/batman-adv/originator.c:1379
batadv_purge_orig+0x17/0x60 net/batman-adv/originator.c:1392
process_one_work+0x864/0x1570 kernel/workqueue.c:2153
worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415


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[syzbot]

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