possible deadlock in console_trylock_spinning (2)

Status: upstream: reported C repro on 2023/11/29 03:09
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+dc57c1cfb6ac07a3c0d2@syzkaller.appspotmail.com
First crash: 989d, last: 26d
Fix commit to backport (bisect log) :
tree: upstream
commit 09c5ba0aa2fcfdadb17d045c3ee6f86d69270df7
Author: John Ogness <john.ogness@linutronix.de>
Date: Thu Apr 21 21:22:48 2022 +0000

  printk: add kthread console printers

  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2024/01/22 linux-5.15.y (ToT) ddcaf4999061 C [report] possible deadlock in console_trylock_spinning
2024/01/22 upstream (ToT) 6613476e225e C Didn't crash
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in console_trylock_spinning serial 4 syz, C done inconclusive 168 1551d 2612d 0/29 auto-obsoleted due to no activity on 2022/10/10 16:31
upstream possible deadlock in console_trylock_spinning (2) serial 4 3 781d 792d 0/29 auto-obsoleted due to no activity on 2024/10/02 11:14
linux-5.15 possible deadlock in console_trylock_spinning 4 4 1091d 1208d 0/3 auto-obsoleted due to no activity on 2023/11/27 19:44
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/07/19 09:54 15m retest repro linux-5.15.y report log
2026/07/19 09:54 13m retest repro linux-5.15.y report log
2026/07/19 09:54 24m retest repro linux-5.15.y report log
2026/07/19 09:54 15m retest repro linux-5.15.y report log
2026/07/19 09:54 15m retest repro linux-5.15.y report log
2026/07/17 05:58 20m retest repro linux-5.15.y report log
2026/07/17 05:58 15m retest repro linux-5.15.y report log
2026/07/17 05:58 15m retest repro linux-5.15.y report log
2026/07/17 05:58 21m retest repro linux-5.15.y no crash log
2026/07/17 05:58 18m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (1)
Created Duration User Patch Repo Result
2024/01/22 12:11 3h47m fix candidate upstream OK (1) job log

Sample crash report:
------------[ cut here ]------------
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/u4:6/4339 is trying to acquire lock:
ffffffff8c110ec0 (console_owner){-...}-{0:0}, at: console_trylock_spinning+0x150/0x350 kernel/printk/printk.c:1879

but task is already holding lock:
ffff8880b912a218 (hrtimer_bases.lock){-.-.}-{2:2}, at: __run_hrtimer kernel/time/hrtimer.c:1694 [inline]
ffff8880b912a218 (hrtimer_bases.lock){-.-.}-{2:2}, at: __hrtimer_run_queues+0x5ff/0xc40 kernel/time/hrtimer.c:1754

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #6 (hrtimer_bases.lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
       lock_hrtimer_base kernel/time/hrtimer.c:168 [inline]
       hrtimer_start_range_ns+0xff/0xc20 kernel/time/hrtimer.c:1289
       hrtimer_start_expires include/linux/hrtimer.h:434 [inline]
       do_start_rt_bandwidth kernel/sched/rt.c:69 [inline]
       start_rt_bandwidth kernel/sched/rt.c:80 [inline]
       inc_rt_group kernel/sched/rt.c:1207 [inline]
       inc_rt_tasks kernel/sched/rt.c:1251 [inline]
       __enqueue_rt_entity kernel/sched/rt.c:1321 [inline]
       enqueue_rt_entity kernel/sched/rt.c:1368 [inline]
       enqueue_task_rt+0x60c/0xc00 kernel/sched/rt.c:1398
       enqueue_task+0x182/0x2b0 kernel/sched/core.c:1996
       __sched_setscheduler+0x1379/0x1be0 kernel/sched/core.c:7570
       _sched_setscheduler kernel/sched/core.c:7617 [inline]
       sched_setscheduler_nocheck kernel/sched/core.c:7664 [inline]
       sched_set_fifo+0xbc/0x120 kernel/sched/core.c:7688
       drm_vblank_worker_init+0x149/0x1a0 drivers/gpu/drm/drm_vblank_work.c:263
       drm_vblank_init+0x265/0x330 drivers/gpu/drm/drm_vblank.c:551
       vkms_create drivers/gpu/drm/vkms/vkms_drv.c:195 [inline]
       vkms_init+0x31a/0x700 drivers/gpu/drm/vkms/vkms_drv.c:233
       do_one_initcall+0x1ee/0x680 init/main.c:1302
       do_initcall_level+0x137/0x1f0 init/main.c:1375
       do_initcalls+0x4b/0x90 init/main.c:1391
       kernel_init_freeable+0x3ce/0x560 init/main.c:1615
       kernel_init+0x19/0x1b0 init/main.c:1506
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #5 (&rt_b->rt_runtime_lock){-...}-{2:2}:
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
       __enable_runtime kernel/sched/rt.c:840 [inline]
       rq_online_rt+0x125/0x310 kernel/sched/rt.c:2331
       set_rq_online kernel/sched/core.c:9056 [inline]
       sched_cpu_activate+0x4ae/0x650 kernel/sched/core.c:9176
       cpuhp_invoke_callback+0x431/0x830 kernel/cpu.c:191
       cpuhp_thread_fun+0x39a/0x7d0 kernel/cpu.c:822
       smpboot_thread_fn+0x4f6/0x970 kernel/smpboot.c:164
       kthread+0x436/0x520 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #4 (&rq->__lock){-.-.}-{2:2}:
       _raw_spin_lock_nested+0x2e/0x40 kernel/locking/spinlock.c:368
       raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
       raw_spin_rq_lock kernel/sched/sched.h:1326 [inline]
       rq_lock kernel/sched/sched.h:1621 [inline]
       task_fork_fair+0x5c/0x350 kernel/sched/fair.c:11499
       sched_cgroup_fork+0x2c6/0x320 kernel/sched/core.c:4485
       copy_process+0x22d1/0x3e00 kernel/fork.c:2395
       kernel_clone+0x219/0x930 kernel/fork.c:2679
       kernel_thread+0xc8/0x120 kernel/fork.c:2731
       rest_init+0x21/0x330 init/main.c:706
       start_kernel+0x486/0x530 init/main.c:1140
       secondary_startup_64_no_verify+0xb1/0xbb

-> #3 (&p->pi_lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
       try_to_wake_up+0x5c/0x1050 kernel/sched/core.c:4049
       __wake_up_common+0x2a4/0x4e0 kernel/sched/wait.c:108
       __wake_up_common_lock kernel/sched/wait.c:138 [inline]
       __wake_up+0x108/0x180 kernel/sched/wait.c:157
       tty_port_default_wakeup+0xa5/0xf0 drivers/tty/tty_port.c:51
       serial8250_tx_chars+0x629/0x830 drivers/tty/serial/8250/8250_port.c:1828
       serial8250_handle_irq+0x519/0x610 drivers/tty/serial/8250/8250_port.c:1924
       serial8250_default_handle_irq+0xb4/0x1a0 drivers/tty/serial/8250/8250_port.c:1941
       serial8250_interrupt+0x9b/0x1c0 drivers/tty/serial/8250/8250_core.c:127
       __handle_irq_event_percpu+0x291/0x9b0 kernel/irq/handle.c:156
       handle_irq_event_percpu kernel/irq/handle.c:196 [inline]
       handle_irq_event+0xa5/0x220 kernel/irq/handle.c:213
       handle_edge_irq+0x243/0xb20 kernel/irq/chip.c:819
       generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
       handle_irq arch/x86/kernel/irq.c:233 [inline]
       __common_interrupt+0xd7/0x1e0 arch/x86/kernel/irq.c:252
       common_interrupt+0xb0/0xd0 arch/x86/kernel/irq.c:242
       asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667
       put_page include/linux/mm.h:1257 [inline]
       filemap_map_pages+0xe8d/0x1390 mm/filemap.c:3351
       do_fault_around mm/memory.c:4243 [inline]
       do_read_fault mm/memory.c:4258 [inline]
       do_fault mm/memory.c:4392 [inline]
       handle_pte_fault mm/memory.c:4650 [inline]
       __handle_mm_fault mm/memory.c:4785 [inline]
       handle_mm_fault+0x2580/0x43c0 mm/memory.c:4883
       do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357
       handle_page_fault arch/x86/mm/fault.c:1445 [inline]
       exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606

-> #2 (&tty->write_wait){-...}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
       __wake_up_common_lock kernel/sched/wait.c:137 [inline]
       __wake_up+0xed/0x180 kernel/sched/wait.c:157
       tty_port_default_wakeup+0xa5/0xf0 drivers/tty/tty_port.c:51
       serial8250_tx_chars+0x629/0x830 drivers/tty/serial/8250/8250_port.c:1828
       serial8250_handle_irq+0x519/0x610 drivers/tty/serial/8250/8250_port.c:1924
       serial8250_default_handle_irq+0xb4/0x1a0 drivers/tty/serial/8250/8250_port.c:1941
       serial8250_interrupt+0x9b/0x1c0 drivers/tty/serial/8250/8250_core.c:127
       __handle_irq_event_percpu+0x291/0x9b0 kernel/irq/handle.c:156
       handle_irq_event_percpu kernel/irq/handle.c:196 [inline]
       handle_irq_event+0xa5/0x220 kernel/irq/handle.c:213
       handle_edge_irq+0x243/0xb20 kernel/irq/chip.c:819
       generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
       handle_irq arch/x86/kernel/irq.c:233 [inline]
       __common_interrupt+0xd7/0x1e0 arch/x86/kernel/irq.c:252
       common_interrupt+0xb0/0xd0 arch/x86/kernel/irq.c:242
       asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667
       native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
       arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
       default_idle+0xb/0x10 arch/x86/kernel/process.c:729
       default_idle_call+0x81/0xc0 kernel/sched/idle.c:112
       cpuidle_idle_call kernel/sched/idle.c:194 [inline]
       do_idle+0x21b/0x5b0 kernel/sched/idle.c:306
       cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403
       start_secondary+0x31f/0x430 arch/x86/kernel/smpboot.c:281
       secondary_startup_64_no_verify+0xb1/0xbb

-> #1 (&port_lock_key){-...}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
       serial8250_console_write+0x170/0xf80 drivers/tty/serial/8250/8250_port.c:3362
       call_console_drivers kernel/printk/printk.c:-1 [inline]
       console_unlock+0xc86/0x1200 kernel/printk/printk.c:2744
       vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
       _printk+0xcc/0x110 kernel/printk/printk.c:2299
       register_console+0x682/0x960 kernel/printk/printk.c:3107
       univ8250_console_init+0x41/0x50 drivers/tty/serial/8250/8250_core.c:690
       console_init+0x177/0x5d0 kernel/printk/printk.c:3207
       start_kernel+0x2f9/0x530 init/main.c:1076
       secondary_startup_64_no_verify+0xb1/0xbb

-> #0 (console_owner){-...}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
       lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
       console_trylock_spinning+0x170/0x350 kernel/printk/printk.c:1896
       vprintk_emit+0xa7/0x150 kernel/printk/printk.c:2273
       _printk+0xcc/0x110 kernel/printk/printk.c:2299
       report_bug+0x1e5/0x2e0 lib/bug.c:195
       handle_bug+0x3a/0x70 arch/x86/kernel/traps.c:239
       exc_invalid_op+0x16/0x40 arch/x86/kernel/traps.c:259
       asm_exc_invalid_op+0x16/0x20 arch/x86/include/asm/idtentry.h:604
       copy_from_user_nofault+0x160/0x1c0 mm/maccess.c:226
       bpf_probe_read_user_common kernel/trace/bpf_trace.c:157 [inline]
       ____bpf_probe_read_compat kernel/trace/bpf_trace.c:281 [inline]
       bpf_probe_read_compat+0xdd/0x170 kernel/trace/bpf_trace.c:277
       bpf_prog_8fc34fd13f997abc+0x3d/0xbc4
       bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline]
       __bpf_prog_run include/linux/filter.h:628 [inline]
       bpf_prog_run include/linux/filter.h:635 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
       bpf_trace_run2+0x15b/0x2d0 kernel/trace/bpf_trace.c:1915
       trace_hrtimer_start include/trace/events/timer.h:199 [inline]
       debug_activate kernel/time/hrtimer.c:466 [inline]
       enqueue_hrtimer+0x314/0x370 kernel/time/hrtimer.c:1074
       __run_hrtimer kernel/time/hrtimer.c:1707 [inline]
       __hrtimer_run_queues+0x65a/0xc40 kernel/time/hrtimer.c:1754
       hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
       local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
       __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
       instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
       sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
       asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
       lock_acquire+0x1f2/0x3f0 kernel/locking/lockdep.c:5627
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
       _raw_spin_lock_bh+0x32/0x50 kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:368 [inline]
       batadv_nc_purge_paths+0xe7/0x3b0 net/batman-adv/network-coding.c:446
       batadv_nc_worker+0x327/0x5c0 net/batman-adv/network-coding.c:726
       process_one_work+0x863/0x1000 kernel/workqueue.c:2310
       worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
       kthread+0x436/0x520 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

other info that might help us debug this:

Chain exists of:
  console_owner --> &rt_b->rt_runtime_lock --> hrtimer_bases.lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(hrtimer_bases.lock);
                               lock(&rt_b->rt_runtime_lock);
                               lock(hrtimer_bases.lock);
  lock(console_owner);

 *** DEADLOCK ***

5 locks held by kworker/u4:6/4339:
 #0: ffff88802b491938 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000334fd00 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff888075458018 (key#18){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
 #2: ffff888075458018 (key#18){+...}-{2:2}, at: batadv_nc_purge_paths+0xe7/0x3b0 net/batman-adv/network-coding.c:446
 #3: ffff8880b912a218 (hrtimer_bases.lock){-.-.}-{2:2}, at: __run_hrtimer kernel/time/hrtimer.c:1694 [inline]
 #3: ffff8880b912a218 (hrtimer_bases.lock){-.-.}-{2:2}, at: __hrtimer_run_queues+0x5ff/0xc40 kernel/time/hrtimer.c:1754
 #4: ffffffff8c11c460 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311

stack backtrace:
CPU: 1 PID: 4339 Comm: kworker/u4:6 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <IRQ>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 console_trylock_spinning+0x170/0x350 kernel/printk/printk.c:1896
 vprintk_emit+0xa7/0x150 kernel/printk/printk.c:2273
 _printk+0xcc/0x110 kernel/printk/printk.c:2299
 report_bug+0x1e5/0x2e0 lib/bug.c:195
 handle_bug+0x3a/0x70 arch/x86/kernel/traps.c:239
 exc_invalid_op+0x16/0x40 arch/x86/kernel/traps.c:259
 asm_exc_invalid_op+0x16/0x20 arch/x86/include/asm/idtentry.h:604
RIP: 0010:copy_from_user_nofault+0x160/0x1c0 mm/maccess.c:226
Code: 24 45 31 f6 31 ff 89 de e8 3d f7 d8 ff 85 db 48 c7 c0 f2 ff ff ff 49 0f 44 c6 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 c0 f3 d8 ff <0f> 0b e9 1c ff ff ff 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c ea fe
RSP: 0018:ffffc90000dd0b90 EFLAGS: 00010006
RAX: ffffffff819ed720 RBX: 0000000000000000 RCX: ffff888029a65940
RDX: 0000000000010000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed100534cb29
R10: ffffed100534cb29 R11: 1ffff1100534cb28 R12: ffff888029a670c8
R13: 00007ffffffff000 R14: ffffc90000dd0bc8 R15: 0000000020000000
 bpf_probe_read_user_common kernel/trace/bpf_trace.c:157 [inline]
 ____bpf_probe_read_compat kernel/trace/bpf_trace.c:281 [inline]
 bpf_probe_read_compat+0xdd/0x170 kernel/trace/bpf_trace.c:277
 bpf_prog_8fc34fd13f997abc+0x3d/0xbc4
 bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
 bpf_trace_run2+0x15b/0x2d0 kernel/trace/bpf_trace.c:1915
 trace_hrtimer_start include/trace/events/timer.h:199 [inline]
 debug_activate kernel/time/hrtimer.c:466 [inline]
 enqueue_hrtimer+0x314/0x370 kernel/time/hrtimer.c:1074
 __run_hrtimer kernel/time/hrtimer.c:1707 [inline]
 __hrtimer_run_queues+0x65a/0xc40 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_acquire+0x1f2/0x3f0 kernel/locking/lockdep.c:5627
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f6 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0018:ffffc9000334fa00 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 7b13d1df46d4ad00
RDX: 0000000000000000 RSI: ffffffff8a0b28c0 RDI: ffffffff8a59a240
RBP: ffffc9000334fb18 R08: dffffc0000000000 R09: fffffbfff1ff7639
R10: fffffbfff1ff7639 R11: 1ffffffff1ff7638 R12: ffff888075458018
R13: 1ffff92000669f4c R14: 0000000000000246 R15: dffffc0000000000
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x32/0x50 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:368 [inline]
 batadv_nc_purge_paths+0xe7/0x3b0 net/batman-adv/network-coding.c:446
 batadv_nc_worker+0x327/0x5c0 net/batman-adv/network-coding.c:726
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
WARNING: CPU: 1 PID: 4339 at mm/maccess.c:226 copy_from_user_nofault+0x160/0x1c0 mm/maccess.c:226
Modules linked in:
CPU: 1 PID: 4339 Comm: kworker/u4:6 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: bat_events batadv_nc_worker
RIP: 0010:copy_from_user_nofault+0x160/0x1c0 mm/maccess.c:226
Code: 24 45 31 f6 31 ff 89 de e8 3d f7 d8 ff 85 db 48 c7 c0 f2 ff ff ff 49 0f 44 c6 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 c0 f3 d8 ff <0f> 0b e9 1c ff ff ff 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c ea fe
RSP: 0018:ffffc90000dd0b90 EFLAGS: 00010006
RAX: ffffffff819ed720 RBX: 0000000000000000 RCX: ffff888029a65940
RDX: 0000000000010000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed100534cb29
R10: ffffed100534cb29 R11: 1ffff1100534cb28 R12: ffff888029a670c8
R13: 00007ffffffff000 R14: ffffc90000dd0bc8 R15: 0000000020000000
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000077dcd000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 bpf_probe_read_user_common kernel/trace/bpf_trace.c:157 [inline]
 ____bpf_probe_read_compat kernel/trace/bpf_trace.c:281 [inline]
 bpf_probe_read_compat+0xdd/0x170 kernel/trace/bpf_trace.c:277
 bpf_prog_8fc34fd13f997abc+0x3d/0xbc4
 bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
 bpf_trace_run2+0x15b/0x2d0 kernel/trace/bpf_trace.c:1915
 trace_hrtimer_start include/trace/events/timer.h:199 [inline]
 debug_activate kernel/time/hrtimer.c:466 [inline]
 enqueue_hrtimer+0x314/0x370 kernel/time/hrtimer.c:1074
 __run_hrtimer kernel/time/hrtimer.c:1707 [inline]
 __hrtimer_run_queues+0x65a/0xc40 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_acquire+0x1f2/0x3f0 kernel/locking/lockdep.c:5627
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f6 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0018:ffffc9000334fa00 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 7b13d1df46d4ad00
RDX: 0000000000000000 RSI: ffffffff8a0b28c0 RDI: ffffffff8a59a240
RBP: ffffc9000334fb18 R08: dffffc0000000000 R09: fffffbfff1ff7639
R10: fffffbfff1ff7639 R11: 1ffffffff1ff7638 R12: ffff888075458018
R13: 1ffff92000669f4c R14: 0000000000000246 R15: dffffc0000000000
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x32/0x50 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:368 [inline]
 batadv_nc_purge_paths+0xe7/0x3b0 net/batman-adv/network-coding.c:446
 batadv_nc_worker+0x327/0x5c0 net/batman-adv/network-coding.c:726
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
----------------
Code disassembly (best guess):
   0:	00 9c 8f 84 24 80 00 	add    %bl,0x802484(%rdi,%rcx,4)
   7:	00 00                	add    %al,(%rax)
   9:	f6 84 24 81 00 00 00 	testb  $0x2,0x81(%rsp)
  10:	02
  11:	0f 85 f6 00 00 00    	jne    0x10d
  17:	41 f7 c6 00 02 00 00 	test   $0x200,%r14d
  1e:	74 01                	je     0x21
  20:	fb                   	sti
  21:	48 c7 44 24 60 0e 36 	movq   $0x45e0360e,0x60(%rsp)
  28:	e0 45
* 2a:	4b c7 44 3d 00 00 00 	movq   $0x0,0x0(%r13,%r15,1) <-- trapping instruction
  31:	00 00
  33:	66 43 c7 44 3d 09 00 	movw   $0x0,0x9(%r13,%r15,1)
  3a:	00
  3b:	43                   	rex.XB
  3c:	c6                   	.byte 0xc6
  3d:	44                   	rex.R
  3e:	3d                   	.byte 0x3d
  3f:	0b                   	.byte 0xb

Crashes (185):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/11 10:31 linux-5.15.y de9476bb4f1b fdeaa69b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/09/06 09:29 linux-5.15.y 7a6c2d093c45 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/07/21 16:44 linux-5.15.y c79648372d02 56d87229 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/05/10 03:41 linux-5.15.y 3b8db0e4f263 77908e5f .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/02/23 07:47 linux-5.15.y c16c81c81336 d34966d1 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2024/07/31 07:48 linux-5.15.y 7e89efd3ae1c 6fde257d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in console_trylock_spinning
2024/01/21 21:31 linux-5.15.y ddcaf4999061 9bd8dcda .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in console_trylock_spinning
2025/12/17 12:27 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/09/06 11:42 linux-5.15.y 7a6c2d093c45 d291dd2d .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/09/06 11:02 linux-5.15.y 7a6c2d093c45 d291dd2d .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/09/06 10:03 linux-5.15.y 7a6c2d093c45 d291dd2d .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/04/29 03:48 linux-5.15.y f7347f400572 aeb6ec69 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/02/16 09:21 linux-5.15.y c16c81c81336 40a34ec9 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/01/27 17:25 linux-5.15.y 003148680b79 d99a33ad .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/01/22 09:10 linux-5.15.y 4735586da88e da72ac06 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/01/09 23:09 linux-5.15.y 4735586da88e 9220929f .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2026/07/02 08:05 linux-5.15.y eceeec79dbc6 27192279 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in console_trylock_spinning
2026/03/04 19:03 linux-5.15.y 91d48252ad4b e6b6b96b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in console_trylock_spinning
2026/01/16 11:58 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2026/01/16 02:40 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2026/01/13 10:15 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2026/01/04 21:34 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/12/26 11:40 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/12/25 05:13 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/12/22 01:24 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/12/19 15:32 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/12/15 14:49 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in console_trylock_spinning
2025/12/13 20:38 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/12/13 04:25 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in console_trylock_spinning
2025/12/09 06:11 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/12/08 07:18 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/12/01 08:56 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/28 12:01 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/26 08:32 linux-5.15.y cc5ec8769306 64219f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in console_trylock_spinning
2025/11/25 13:54 linux-5.15.y cc5ec8769306 64219f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/24 23:05 linux-5.15.y cc5ec8769306 bf6fe8fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/24 15:47 linux-5.15.y cc5ec8769306 bf6fe8fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/23 05:31 linux-5.15.y cc5ec8769306 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in console_trylock_spinning
2025/11/20 04:58 linux-5.15.y cc5ec8769306 26ee5237 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/19 04:58 linux-5.15.y cc5ec8769306 ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/16 13:21 linux-5.15.y cc5ec8769306 f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/15 06:56 linux-5.15.y cc5ec8769306 f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/13 06:30 linux-5.15.y cc5ec8769306 07e030de .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/11 10:00 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/10 20:28 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/08 07:01 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/07 22:33 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/07 10:15 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/04 02:19 linux-5.15.y cc5ec8769306 686bf657 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/11/03 07:28 linux-5.15.y cc5ec8769306 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/10/27 10:11 linux-5.15.y ac56c046adf4 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/10/16 15:29 linux-5.15.y 29e53a5b1c4f 19568248 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/10/15 07:20 linux-5.15.y 29e53a5b1c4f b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in console_trylock_spinning
2025/10/13 07:00 linux-5.15.y 29e53a5b1c4f ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/10/08 23:10 linux-5.15.y 29e53a5b1c4f 7e2882b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/10/07 09:53 linux-5.15.y 29e53a5b1c4f 8ef35d49 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/10/03 23:53 linux-5.15.y 29e53a5b1c4f 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/10/03 18:50 linux-5.15.y 29e53a5b1c4f 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/09/21 21:08 linux-5.15.y 43bb85222e53 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in console_trylock_spinning
2025/09/13 09:31 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in console_trylock_spinning
2025/09/13 03:44 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/09/10 18:30 linux-5.15.y de9476bb4f1b fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in console_trylock_spinning
2025/08/30 17:03 linux-5.15.y 01879f56bdde 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/08/28 00:36 linux-5.15.y c79648372d02 e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf possible deadlock in console_trylock_spinning
2025/05/17 20:47 linux-5.15.y 3b8db0e4f263 f41472b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in console_trylock_spinning
2023/11/29 03:08 linux-5.15.y a78d278e01b1 1adfb6f6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in console_trylock_spinning
* Struck through repros no longer work on HEAD.