INFO: task hung in path_openat (2)

[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=12805d01b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=f693f78234b636a634ce
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+f693f7...@syzkaller.appspotmail.com

ieee802154 phy1 wpan1: encryption failed: -22
ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
INFO: task syz-executor.3:32161 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.3 D29744 32161 11979 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+0x4f/0x90 kernel/locking/rwsem.c:72
inode_lock include/linux/fs.h:748 [inline]
do_last fs/namei.c:3324 [inline]
path_openat+0x1071/0x2df0 fs/namei.c:3537
do_filp_open+0x18c/0x3f0 fs/namei.c:3567
do_sys_open+0x3b3/0x520 fs/open.c:1085
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fd514519ae9
Code: Bad RIP value.
RSP: 002b:00007fd511a4d188 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fd51462d0e0 RCX: 00007fd514519ae9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200003c0
RBP: 00007fd514573f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd39caa1bf R14: 00007fd511a4d300 R15: 0000000000022000
INFO: task syz-executor.3:32189 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.3 D29720 32189 11979 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_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline]
rwsem_down_read_failed+0x20a/0x390 kernel/locking/rwsem-xadd.c:309
call_rwsem_down_read_failed+0x14/0x30 arch/x86/lib/rwsem.S:94
__down_read arch/x86/include/asm/rwsem.h:83 [inline]
down_read+0x44/0x80 kernel/locking/rwsem.c:26
inode_lock_shared include/linux/fs.h:758 [inline]
lookup_slow fs/namei.c:1688 [inline]
walk_component+0x798/0xda0 fs/namei.c:1811
lookup_last fs/namei.c:2274 [inline]
path_lookupat+0x1ff/0x8d0 fs/namei.c:2319
filename_lookup+0x1ac/0x5a0 fs/namei.c:2349
user_path include/linux/namei.h:62 [inline]
do_mount+0x147/0x2f50 fs/namespace.c:2762
ksys_mount+0xcf/0x130 fs/namespace.c:3038
__do_sys_mount fs/namespace.c:3052 [inline]
__se_sys_mount fs/namespace.c:3049 [inline]
__x64_sys_mount+0xba/0x150 fs/namespace.c:3049
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fd514519ae9
Code: Bad RIP value.
RSP: 002b:00007fd511a0b188 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fd51462d260 RCX: 00007fd514519ae9
RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000000
RBP: 00007fd514573f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd39caa1bf R14: 00007fd511a0b300 R15: 0000000000022000

Showing all locks held in the system:
1 lock held by khungtaskd/1570:
#0: 0000000019c54d5a (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
1 lock held by systemd-journal/4688:
#0: 00000000925ce984 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1826 [inline]
#0: 00000000925ce984 (&rq->lock){-.-.}, at: __schedule+0x1f9/0x2040 kernel/sched/core.c:3455
1 lock held by in:imklog/7801:
#0: 00000000a9e92713 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767
3 locks held by kworker/u4:11/10510:
#0: 00000000925ce984 (&rq->lock){-.-.}, at: idle_balance kernel/sched/fair.c:9702 [inline]
#0: 00000000925ce984 (&rq->lock){-.-.}, at: pick_next_task_fair+0x556/0x1570 kernel/sched/fair.c:6841
#1: 0000000019c54d5a (rcu_read_lock){....}, at: cpu_of kernel/sched/sched.h:923 [inline]
#1: 0000000019c54d5a (rcu_read_lock){....}, at: __update_idle_core+0x39/0x3e0 kernel/sched/fair.c:6057
#2: 00000000dec9f94b (&base->lock){-.-.}, at: lock_timer_base+0x55/0x1b0 kernel/time/timer.c:950
1 lock held by syz-executor.3/32156:
#0: 0000000063e929b1 (&sb->s_type->i_mutex_key#27){++++}, at: inode_lock_shared include/linux/fs.h:758 [inline]
#0: 0000000063e929b1 (&sb->s_type->i_mutex_key#27){++++}, at: lookup_slow fs/namei.c:1688 [inline]
#0: 0000000063e929b1 (&sb->s_type->i_mutex_key#27){++++}, at: walk_component+0x798/0xda0 fs/namei.c:1811
2 locks held by syz-executor.3/32161:
#0: 00000000f4bdf5ed (sb_writers#21){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline]
#0: 00000000f4bdf5ed (sb_writers#21){.+.+}, at: mnt_want_write+0x3a/0xb0 fs/namespace.c:360
#1: 0000000063e929b1 (&sb->s_type->i_mutex_key#27){++++}, at: inode_lock include/linux/fs.h:748 [inline]
#1: 0000000063e929b1 (&sb->s_type->i_mutex_key#27){++++}, at: do_last fs/namei.c:3324 [inline]
#1: 0000000063e929b1 (&sb->s_type->i_mutex_key#27){++++}, at: path_openat+0x1071/0x2df0 fs/namei.c:3537
1 lock held by syz-executor.3/32189:
#0: 0000000063e929b1 (&sb->s_type->i_mutex_key#27){++++}, at: inode_lock_shared include/linux/fs.h:758 [inline]
#0: 0000000063e929b1 (&sb->s_type->i_mutex_key#27){++++}, at: lookup_slow fs/namei.c:1688 [inline]
#0: 0000000063e929b1 (&sb->s_type->i_mutex_key#27){++++}, at: walk_component+0x798/0xda0 fs/namei.c:1811

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

NMI backtrace for cpu 0
CPU: 0 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4688 Comm: systemd-journal Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:preempt_count_add+0x64/0x190 kernel/sched/core.c:3238
Code: 0b 85 c9 75 07 65 8b 05 ea 70 c0 7e 48 b8 00 00 00 00 00 fc ff df 48 89 da 83 e3 07 48 c1 ea 03 83 c3 03 65 01 2d cc 70 c0 7e <0f> b6 04 02 38 c3 7c 08 84 c0 0f 85 da 00 00 00 8b 15 c6 c8 e2 0b
RSP: 0018:ffff8880a1137990 EFLAGS: 00000282
RAX: dffffc0000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 1ffffffff1a486ec RSI: ffff8880a1137938 RDI: 0000000000000001
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001
R10: ffff8880a1137b37 R11: 0000000000074071 R12: ffff8880a1137b20
R13: 0000000000000000 R14: ffff8880a1137ad8 R15: 0000000000001000
FS: 00007fb2291c68c0(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb226247000 CR3: 00000000a1bac000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
unwind_next_frame+0x135/0x1400 arch/x86/kernel/unwind_orc.c:407
__save_stack_trace+0x9f/0x190 arch/x86/kernel/stacktrace.c:44
save_stack mm/kasan/kasan.c:448 [inline]
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:553
kmem_cache_alloc+0x122/0x370 mm/slab.c:3559
getname_flags+0xce/0x590 fs/namei.c:140
user_path_at_empty+0x2a/0x50 fs/namei.c:2609
user_path_at include/linux/namei.h:57 [inline]
do_faccessat+0x248/0x7a0 fs/open.c:397
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fb2284819c7
Code: 83 c4 08 48 3d 01 f0 ff ff 73 01 c3 48 8b 0d c8 d4 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 15 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d4 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007ffc036e3ca8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015
RAX: ffffffffffffffda RBX: 00007ffc036e6bc0 RCX: 00007fb2284819c7
RDX: 00007fb228ef2a00 RSI: 0000000000000000 RDI: 0000562bb5c609a3
RBP: 00007ffc036e3ce0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ffc036e6bc0 R15: 00007ffc036e41d0
----------------
Code disassembly (best guess):
0: 0b 85 c9 75 07 65 or 0x650775c9(%rbp),%eax
6: 8b 05 ea 70 c0 7e mov 0x7ec070ea(%rip),%eax # 0x7ec070f6
c: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
13: fc ff df
16: 48 89 da mov %rbx,%rdx
19: 83 e3 07 and $0x7,%ebx
1c: 48 c1 ea 03 shr $0x3,%rdx
20: 83 c3 03 add $0x3,%ebx
23: 65 01 2d cc 70 c0 7e add %ebp,%gs:0x7ec070cc(%rip) # 0x7ec070f6
* 2a: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction
2e: 38 c3 cmp %al,%bl
30: 7c 08 jl 0x3a
32: 84 c0 test %al,%al
34: 0f 85 da 00 00 00 jne 0x114
3a: 8b 15 c6 c8 e2 0b mov 0xbe2c8c6(%rip),%edx # 0xbe2c906


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[syzbot]

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