Re: [syzbot] [block?] INFO: task hung in bdev_release

syzbot
2023-12-16T13:31:06Z

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: task hung in bdev_release

INFO: task syz-executor.0:5519 blocked for more than 143 seconds.
Not tainted 6.7.0-rc2-next-20231124-syzkaller-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0 state:D stack:28208 pid:5519 tgid:5519 ppid:5421 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5399 [inline]
__schedule+0xf15/0x5c00 kernel/sched/core.c:6726
__schedule_loop kernel/sched/core.c:6801 [inline]
schedule+0xe7/0x270 kernel/sched/core.c:6816
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6873
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x5b4/0x9c0 kernel/locking/mutex.c:747
bdev_release+0xe6/0xac0 block/bdev.c:973
blkdev_release+0x37/0x50 block/fops.c:616
__fput+0x270/0xbb0 fs/file_table.c:394
__fput_sync+0x47/0x50 fs/file_table.c:475
__do_sys_close fs/open.c:1591 [inline]
__se_sys_close fs/open.c:1576 [inline]
__x64_sys_close+0x86/0xf0 fs/open.c:1576
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x62/0x6a
RIP: 0033:0x7fc4db47b9da
RSP: 002b:00007fff600ff100 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007fc4db47b9da
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007fc4db59d980 R08: 0000001b2e860000 R09: 0000000000000001
R10: 00007fff601ac080 R11: 0000000000000293 R12: 000000000001c90d
R13: ffffffffffffffff R14: 00007fc4db000000 R15: 000000000001c5cc
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
#0: ffffffff8cfacf60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:301 [inline]
#0: ffffffff8cfacf60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline]
#0: ffffffff8cfacf60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6613
2 locks held by getty/4821:
#0: ffff8880272c20a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfc4/0x1490 drivers/tty/n_tty.c:2201
1 lock held by udevd/5406:
#0: ffff88801da974c8 (&disk->open_mutex){+.+.}-{3:3}, at: bdev_open_by_dev+0x27c/0xed0 block/bdev.c:859
1 lock held by syz-executor.0/5519:
#0: ffff88801da974c8 (&disk->open_mutex){+.+.}-{3:3}, at: bdev_release+0xe6/0xac0 block/bdev.c:973
1 lock held by syz-executor.0/5806:
#0: ffff88801da974c8 (&disk->open_mutex){+.+.}-{3:3}, at: bdev_open_by_dev+0x27c/0xed0 block/bdev.c:859
1 lock held by syz-executor.0/5823:
#0: ffff88801da974c8 (&disk->open_mutex){+.+.}-{3:3}, at: bdev_open_by_dev+0x27c/0xed0 block/bdev.c:859

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

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted 6.7.0-rc2-next-20231124-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
nmi_cpu_backtrace+0x277/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x299/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xf86/0x1210 kernel/hung_task.c:379
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 48 Comm: kworker/u4:3 Not tainted 6.7.0-rc2-next-20231124-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:find_held_lock+0x9/0x110 kernel/locking/lockdep.c:5236
Code: 0d a5 77 00 e9 18 ff ff ff e8 03 a5 77 00 4c 8d 44 24 20 eb 95 66 66 2e 0f 1f 84 00 00 00 00 00 90 41 57 44 8d 7a ff 49 63 c7 <41> 56 49 89 ce 48 8d 04 80 41 55 49 89 f5 41 54 55 89 d5 53 48 8d
RSP: 0018:ffffc90000b8eff8 EFLAGS: 00000006
RAX: 0000000000000004 RBX: 0000000000000003 RCX: ffffc90000b8f058
RDX: 0000000000000005 RSI: ffff8880b9840860 RDI: ffff888019edbb80
RBP: 1ffff92000171e03 R08: 0000000000000000 R09: fffffbfff1e32732
R10: ffffffff8f193997 R11: 0000000000000004 R12: ffff8880b9840860
R13: 0000000000000005 R14: ffff888019edc638 R15: 0000000000000004
FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd39e31e4c CR3: 000000000cd78000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
__lock_release kernel/locking/lockdep.c:5428 [inline]
lock_release+0x1fd/0x6a0 kernel/locking/lockdep.c:5773
local_lock_release include/linux/local_lock_internal.h:38 [inline]
___slab_alloc+0x98b/0x1700 mm/slub.c:3139
__slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3297
__slab_alloc_node mm/slub.c:3350 [inline]
slab_alloc_node mm/slub.c:3442 [inline]
__kmem_cache_alloc_node+0x131/0x310 mm/slub.c:3491
__do_kmalloc_node mm/slab_common.c:1006 [inline]
__kmalloc+0x49/0x90 mm/slab_common.c:1020
kmalloc include/linux/slab.h:604 [inline]
kzalloc include/linux/slab.h:721 [inline]
ieee802_11_parse_elems_full+0xee/0x13a0 net/mac80211/util.c:1628
ieee802_11_parse_elems_crc net/mac80211/ieee80211_i.h:2288 [inline]
ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2295 [inline]
ieee80211_inform_bss+0x120/0x1150 net/mac80211/scan.c:79
rdev_inform_bss+0xf9/0x440 net/wireless/rdev-ops.h:418
cfg80211_inform_single_bss_frame_data+0x7b7/0xf40 net/wireless/scan.c:2909
cfg80211_inform_bss_frame_data+0xbf/0x290 net/wireless/scan.c:2936
ieee80211_bss_info_update+0x300/0x8f0 net/mac80211/scan.c:205
ieee80211_rx_bss_info net/mac80211/ibss.c:1098 [inline]
ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1577 [inline]
ieee80211_ibss_rx_queued_mgmt+0x198a/0x3140 net/mac80211/ibss.c:1604
ieee80211_iface_process_skb net/mac80211/iface.c:1589 [inline]
ieee80211_iface_work+0xa67/0xda0 net/mac80211/iface.c:1643
cfg80211_wiphy_work+0x24e/0x330 net/wireless/core.c:435
process_one_work+0x8a4/0x15f0 kernel/workqueue.c:2633
process_scheduled_works kernel/workqueue.c:2706 [inline]
worker_thread+0x8b6/0x1290 kernel/workqueue.c:2787
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
</TASK>

Tested on:

commit: 8c9660f6 Add linux-next specific files for 20231124
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=13446c06e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=ca1e8655505e280
dashboard link: https://syzkaller.appspot.com/bug?extid=4da851837827326a7cd4
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=165e748ae80000