syzbot


possible deadlock in work_grab_pending

Status: upstream: reported on 2024/08/22 08:45
Subsystems: bpf
[Documentation on labels]
Reported-by: syzbot+fbf8ab9c22c12e84f438@syzkaller.appspotmail.com
First crash: 27d, last: 27d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bpf?] possible deadlock in work_grab_pending 0 (1) 2024/08/22 08:45

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.11.0-rc3-next-20240816-syzkaller #0 Not tainted
------------------------------------------------------
swapper/1/0 is trying to acquire lock:
ffff8880158a0018 (&pool->lock){-.-.}-{2:2}, at: try_to_grab_pending kernel/workqueue.c:2084 [inline]
ffff8880158a0018 (&pool->lock){-.-.}-{2:2}, at: work_grab_pending+0x294/0xae0 kernel/workqueue.c:2160

but task is already holding lock:
ffff8880b9129430 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:3312 [inline]
ffff8880b9129430 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3724 [inline]
ffff8880b9129430 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3810

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (krc.lock){..-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5762
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
       krc_this_cpu_lock kernel/rcu/tree.c:3312 [inline]
       add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3724 [inline]
       kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3810
       trie_delete_elem+0x546/0x6a0 kernel/bpf/lpm_trie.c:540
       0xffffffffa0001fe3
       bpf_dispatcher_nop_func include/linux/bpf.h:1252 [inline]
       __bpf_prog_run include/linux/filter.h:691 [inline]
       bpf_prog_run include/linux/filter.h:698 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2338 [inline]
       bpf_trace_run4+0x334/0x590 kernel/trace/bpf_trace.c:2381
       trace_sched_switch include/trace/events/sched.h:222 [inline]
       __schedule+0x2591/0x4ad0 kernel/sched/core.c:6636
       preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6818
       preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6842
       preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
       class_preempt_destructor include/linux/preempt.h:480 [inline]
       try_to_wake_up+0x9a1/0x1470 kernel/sched/core.c:4236
       wake_up_process kernel/sched/core.c:4361 [inline]
       wake_up_q+0xc8/0x120 kernel/sched/core.c:1056
       futex_wake+0x523/0x5c0 kernel/futex/waitwake.c:199
       do_futex+0x392/0x560 kernel/futex/syscalls.c:107
       __do_sys_futex kernel/futex/syscalls.c:179 [inline]
       __se_sys_futex+0x3f9/0x480 kernel/futex/syscalls.c:160
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&rq->__lock){-.-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5762
       _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:587
       raw_spin_rq_lock kernel/sched/sched.h:1485 [inline]
       task_rq_lock+0xc6/0x360 kernel/sched/core.c:689
       cgroup_move_task+0x92/0x2d0 kernel/sched/psi.c:1161
       css_set_move_task+0x72e/0x950 kernel/cgroup/cgroup.c:898
       cgroup_post_fork+0x256/0x880 kernel/cgroup/cgroup.c:6690
       copy_process+0x3ab1/0x3e30 kernel/fork.c:2620
       kernel_clone+0x226/0x8f0 kernel/fork.c:2806
       user_mode_thread+0x132/0x1a0 kernel/fork.c:2884
       rest_init+0x23/0x300 init/main.c:712
       start_kernel+0x47a/0x500 init/main.c:1103
       x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:507
       x86_64_start_kernel+0x9f/0xa0 arch/x86/kernel/head64.c:488
       common_startup_64+0x13e/0x147

-> #1 (&p->pi_lock){-.-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5762
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline]
       try_to_wake_up+0xb0/0x1470 kernel/sched/core.c:4113
       create_worker+0x507/0x720 kernel/workqueue.c:2828
       workqueue_init+0x520/0x8a0 kernel/workqueue.c:7902
       kernel_init_freeable+0x3fe/0x5d0 init/main.c:1562
       kernel_init+0x1d/0x2b0 init/main.c:1467
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (&pool->lock){-.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3136 [inline]
       check_prevs_add kernel/locking/lockdep.c:3255 [inline]
       validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3871
       __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5145
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5762
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
       try_to_grab_pending kernel/workqueue.c:2084 [inline]
       work_grab_pending+0x294/0xae0 kernel/workqueue.c:2160
       mod_delayed_work_on+0xd4/0x370 kernel/workqueue.c:2588
       kvfree_call_rcu+0x47f/0x790 kernel/rcu/tree.c:3838
       cfg80211_update_known_bss+0xb39/0x1500 net/wireless/scan.c:1891
       __cfg80211_bss_update+0x153/0x2170 net/wireless/scan.c:1937
       cfg80211_inform_single_bss_data+0xd51/0x2030 net/wireless/scan.c:2331
       cfg80211_inform_bss_data+0x3dd/0x5a70 net/wireless/scan.c:3159
       cfg80211_inform_bss_frame_data+0x3b8/0x720 net/wireless/scan.c:3254
       ieee80211_bss_info_update+0x8a7/0xbc0 net/mac80211/scan.c:226
       ieee80211_scan_rx+0x526/0x9c0 net/mac80211/scan.c:340
       __ieee80211_rx_handle_packet net/mac80211/rx.c:5225 [inline]
       ieee80211_rx_list+0x2b02/0x3780 net/mac80211/rx.c:5462
       ieee80211_rx_napi+0x18a/0x3c0 net/mac80211/rx.c:5485
       ieee80211_rx include/net/mac80211.h:5124 [inline]
       ieee80211_handle_queued_frames+0xe7/0x1e0 net/mac80211/main.c:439
       tasklet_action_common+0x321/0x4d0 kernel/softirq.c:785
       handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
       __do_softirq kernel/softirq.c:588 [inline]
       invoke_softirq kernel/softirq.c:428 [inline]
       __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
       irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
       instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline]
       sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1037
       asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
       native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
       arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline]
       acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111
       acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:702
       cpuidle_enter_state+0x112/0x480 drivers/cpuidle/cpuidle.c:267
       cpuidle_enter+0x5d/0xa0 drivers/cpuidle/cpuidle.c:388
       call_cpuidle kernel/sched/idle.c:155 [inline]
       cpuidle_idle_call kernel/sched/idle.c:230 [inline]
       do_idle+0x375/0x5d0 kernel/sched/idle.c:326
       cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:424
       __pfx_ap_starting+0x0/0x10 arch/x86/kernel/smpboot.c:313
       common_startup_64+0x13e/0x147

other info that might help us debug this:

Chain exists of:
  &pool->lock --> &rq->__lock --> krc.lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(krc.lock);
                               lock(&rq->__lock);
                               lock(krc.lock);
  lock(&pool->lock);

 *** DEADLOCK ***

4 locks held by swapper/1/0:
 #0: ffffffff8e939720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e939720 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e939720 (rcu_read_lock){....}-{1:2}, at: ieee80211_rx_napi+0xd6/0x3c0 net/mac80211/rx.c:5484
 #1: ffff8880799c0168 (&rdev->bss_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
 #1: ffff8880799c0168 (&rdev->bss_lock){+.-.}-{2:2}, at: cfg80211_inform_single_bss_data+0xd3d/0x2030 net/wireless/scan.c:2330
 #2: ffff8880b9129430 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:3312 [inline]
 #2: ffff8880b9129430 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3724 [inline]
 #2: ffff8880b9129430 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3810
 #3: ffffffff8e939720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #3: ffffffff8e939720 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #3: ffffffff8e939720 (rcu_read_lock){....}-{1:2}, at: try_to_grab_pending kernel/workqueue.c:2075 [inline]
 #3: ffffffff8e939720 (rcu_read_lock){....}-{1:2}, at: work_grab_pending+0x1d3/0xae0 kernel/workqueue.c:2160

stack backtrace:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.11.0-rc3-next-20240816-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2189
 check_prev_add kernel/locking/lockdep.c:3136 [inline]
 check_prevs_add kernel/locking/lockdep.c:3255 [inline]
 validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3871
 __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5145
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5762
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 try_to_grab_pending kernel/workqueue.c:2084 [inline]
 work_grab_pending+0x294/0xae0 kernel/workqueue.c:2160
 mod_delayed_work_on+0xd4/0x370 kernel/workqueue.c:2588
 kvfree_call_rcu+0x47f/0x790 kernel/rcu/tree.c:3838
 cfg80211_update_known_bss+0xb39/0x1500 net/wireless/scan.c:1891
 __cfg80211_bss_update+0x153/0x2170 net/wireless/scan.c:1937
 cfg80211_inform_single_bss_data+0xd51/0x2030 net/wireless/scan.c:2331
 cfg80211_inform_bss_data+0x3dd/0x5a70 net/wireless/scan.c:3159
 cfg80211_inform_bss_frame_data+0x3b8/0x720 net/wireless/scan.c:3254
 ieee80211_bss_info_update+0x8a7/0xbc0 net/mac80211/scan.c:226
 ieee80211_scan_rx+0x526/0x9c0 net/mac80211/scan.c:340
 __ieee80211_rx_handle_packet net/mac80211/rx.c:5225 [inline]
 ieee80211_rx_list+0x2b02/0x3780 net/mac80211/rx.c:5462
 ieee80211_rx_napi+0x18a/0x3c0 net/mac80211/rx.c:5485
 ieee80211_rx include/net/mac80211.h:5124 [inline]
 ieee80211_handle_queued_frames+0xe7/0x1e0 net/mac80211/main.c:439
 tasklet_action_common+0x321/0x4d0 kernel/softirq.c:785
 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1037
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:92 [inline]
RIP: 0010:acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:112
Code: 90 90 90 90 90 90 90 90 90 65 48 8b 04 25 80 d7 03 00 48 f7 00 08 00 00 00 75 10 66 90 0f 00 2d d5 69 ae 00 f3 0f 1e fa fb f4 <fa> c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90
RSP: 0018:ffffc900001a7d08 EFLAGS: 00000246
RAX: ffff888017ec0000 RBX: ffff88801bea9864 RCX: 000000000019e8c9
RDX: 0000000000000001 RSI: ffff88801bea9800 RDI: ffff88801bea9864
RBP: 000000000003a6f8 R08: ffff8880b9137c7b R09: 1ffff11017226f8f
R10: dffffc0000000000 R11: ffffffff8bbbf1e0 R12: ffff888018b56000
R13: 0000000000000000 R14: 0000000000000001 R15: ffffffff8f0e8660
 acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:702
 cpuidle_enter_state+0x112/0x480 drivers/cpuidle/cpuidle.c:267
 cpuidle_enter+0x5d/0xa0 drivers/cpuidle/cpuidle.c:388
 call_cpuidle kernel/sched/idle.c:155 [inline]
 cpuidle_idle_call kernel/sched/idle.c:230 [inline]
 do_idle+0x375/0x5d0 kernel/sched/idle.c:326
 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:424
 start_secondary+0x100/0x100 arch/x86/kernel/smpboot.c:313
 common_startup_64+0x13e/0x147
 </TASK>
----------------
Code disassembly (best guess):
   0:	90                   	nop
   1:	90                   	nop
   2:	90                   	nop
   3:	90                   	nop
   4:	90                   	nop
   5:	90                   	nop
   6:	90                   	nop
   7:	90                   	nop
   8:	90                   	nop
   9:	65 48 8b 04 25 80 d7 	mov    %gs:0x3d780,%rax
  10:	03 00
  12:	48 f7 00 08 00 00 00 	testq  $0x8,(%rax)
  19:	75 10                	jne    0x2b
  1b:	66 90                	xchg   %ax,%ax
  1d:	0f 00 2d d5 69 ae 00 	verw   0xae69d5(%rip)        # 0xae69f9
  24:	f3 0f 1e fa          	endbr64
  28:	fb                   	sti
  29:	f4                   	hlt
* 2a:	fa                   	cli <-- trapping instruction
  2b:	c3                   	ret
  2c:	cc                   	int3
  2d:	cc                   	int3
  2e:	cc                   	int3
  2f:	cc                   	int3
  30:	66 0f 1f 84 00 00 00 	nopw   0x0(%rax,%rax,1)
  37:	00 00
  39:	90                   	nop
  3a:	90                   	nop
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/08/18 08:43 linux-next 367b5c3d53e5 dbc93b08 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in work_grab_pending
* Struck through repros no longer work on HEAD.