Re: [syzbot] [jfs?] INFO: task hung in txBegin

syzbot
2024-06-27T03:14:03Z

Hello,

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

INFO: task kworker/u8:6:1105 blocked for more than 143 seconds.
Not tainted 6.10.0-rc4-syzkaller-00148-g50736169ecc8-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:6 state:D stack:22288 pid:1105 tgid:1105 ppid:2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5408 [inline]
__schedule+0x1796/0x49d0 kernel/sched/core.c:6745
__schedule_loop kernel/sched/core.c:6822 [inline]
schedule+0x14b/0x320 kernel/sched/core.c:6837
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
rwsem_down_write_slowpath+0xeeb/0x13b0 kernel/locking/rwsem.c:1178
__down_write_common+0x1af/0x200 kernel/locking/rwsem.c:1306
wb_writeback+0x143/0xda0 fs/fs-writeback.c:2083
wb_do_writeback fs/fs-writeback.c:2279 [inline]
wb_workfn+0x410/0x1090 fs/fs-writeback.c:2319
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
worker_thread+0x86d/0xd70 kernel/workqueue.c:3393
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
INFO: task syz-executor:5687 blocked for more than 143 seconds.
Not tainted 6.10.0-rc4-syzkaller-00148-g50736169ecc8-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:20288 pid:5687 tgid:5687 ppid:1 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5408 [inline]
__schedule+0x1796/0x49d0 kernel/sched/core.c:6745
__schedule_loop kernel/sched/core.c:6822 [inline]
schedule+0x14b/0x320 kernel/sched/core.c:6837
wb_wait_for_completion+0x166/0x290 fs/fs-writeback.c:216
__writeback_inodes_sb_nr+0x2d2/0x380 fs/fs-writeback.c:2711
sync_filesystem+0xa4/0x230 fs/sync.c:54
generic_shutdown_super+0x72/0x2d0 fs/super.c:621
kill_block_super+0x44/0x90 fs/super.c:1676
deactivate_locked_super+0xc4/0x130 fs/super.c:473
cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1267
task_work_run+0x24f/0x310 kernel/task_work.c:180
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218
do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6f9d87e257
RSP: 002b:00007fff1d6cb318 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f6f9d87e257
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff1d6cb3d0
RBP: 00007fff1d6cb3d0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fff1d6cc480
R13: 00007f6f9d8d96c6 R14: 000000000001846f R15: 0000000000000001
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
#0: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
#0: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614
3 locks held by kworker/u8:6/1105:
#0: ffff88801aef9148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline]
#0: ffff88801aef9148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312
#1: ffffc90004117d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline]
#1: ffffc90004117d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312
#2: ffff88801cf800e0 (&type->s_umount_key#52){+.+.}-{3:3}, at: wb_writeback+0x143/0xda0 fs/fs-writeback.c:2083
2 locks held by getty/4837:
#0: ffff88802b0160a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5687:
#0: ffff88801cf800e0 (&type->s_umount_key#52){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
#0: ffff88801cf800e0 (&type->s_umount_key#52){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
#0: ffff88801cf800e0 (&type->s_umount_key#52){+.+.}-{3:3}, at: deactivate_super+0xb5/0xf0 fs/super.c:505

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

NMI backtrace for cpu 1
CPU: 1 PID: 30 Comm: khungtaskd Not tainted 6.10.0-rc4-syzkaller-00148-g50736169ecc8-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
watchdog+0xfde/0x1020 kernel/hung_task.c:379
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3962 Comm: kworker/u8:10 Not tainted 6.10.0-rc4-syzkaller-00148-g50736169ecc8-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:173 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:236 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0x9d/0x120 kernel/kcov.c:341
Code: 00 00 4d 85 d2 0f 84 8b 00 00 00 4c 8b 4c 24 20 65 4c 8b 1c 25 80 d4 03 00 31 d2 eb 08 48 ff c2 49 39 d2 74 71 4c 8b 74 d6 10 <65> 8b 05 c4 a9 6d 7e a9 00 01 ff 00 74 11 a9 00 01 00 00 74 de 41
RSP: 0018:ffffc9000c266798 EFLAGS: 00000212
RAX: 0000000000000000 RBX: 0000000000000016 RCX: ffff88802e735a00
RDX: 000000000000001b RSI: ffffffff8f8548d0 RDI: 0000000000000003
RBP: ffffc9000c266bb0 R08: 0000000000000001 R09: ffffffff8afbe03a
R10: 0000000000000028 R11: ffff88802e735a00 R12: ffff888021f2e02f
R13: dffffc0000000000 R14: 000000000000007f R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556005801600 CR3: 000000000e132000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
_ieee802_11_parse_elems_full+0x6da/0x49f0 net/mac80211/parse.c:215
ieee802_11_parse_elems_full+0xde7/0x2870 net/mac80211/parse.c:902
ieee802_11_parse_elems_crc net/mac80211/ieee80211_i.h:2332 [inline]
ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2339 [inline]
ieee80211_inform_bss+0x15f/0x1080 net/mac80211/scan.c:79
rdev_inform_bss net/wireless/rdev-ops.h:418 [inline]
cfg80211_inform_single_bss_data+0x1121/0x2360 net/wireless/scan.c:2293
cfg80211_inform_bss_data+0x3dd/0x5a70 net/wireless/scan.c:3117
cfg80211_inform_bss_frame_data+0x3bc/0x720 net/wireless/scan.c:3207
ieee80211_bss_info_update+0x8a7/0xbc0 net/mac80211/scan.c:226
ieee80211_rx_bss_info net/mac80211/ibss.c:1099 [inline]
ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1578 [inline]
ieee80211_ibss_rx_queued_mgmt+0x1962/0x2d70 net/mac80211/ibss.c:1605
ieee80211_iface_process_skb net/mac80211/iface.c:1603 [inline]
ieee80211_iface_work+0x8a3/0xf10 net/mac80211/iface.c:1657
cfg80211_wiphy_work+0x221/0x260 net/wireless/core.c:437
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
worker_thread+0x86d/0xd70 kernel/workqueue.c:3393
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

Tested on:

commit: 50736169 Merge tag 'for-6.10-rc4-tag' of git://git.ker..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=11f12b3e980000
kernel config: https://syzkaller.appspot.com/x/.config?x=12f98862a3c0c799
dashboard link: https://syzkaller.appspot.com/bug?extid=eda89a33c5856f66f823
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=148dfb01980000