syzbot
INFO: rcu detected stall in v4l2_release (4)
Status: auto-obsoleted due to no activity on 2026/07/18 17:10
Subsystems:
mm
Labels:
prio:normal
[Documentation on labels]
First crash: 97d, last: 97d
Sample crash report:
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9024/1:b..l
rcu: (detected by 0, t=10503 jiffies, g=33593, q=1261 ncpus=2)
task:syz.0.766 state:R running task stack:25928 pid:9024 tgid:9019 ppid:5807 task_flags:0x40054c flags:0x00080003
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5387 [inline]
__schedule+0x10e9/0x6820 kernel/sched/core.c:7188
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7512
irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:476 [inline]
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline]
irqentry_exit+0x1fe/0x790 kernel/entry/common.c:164
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline]
RIP: 0010:lock_release+0x240/0x310 kernel/locking/lockdep.c:5879
Code: fe ff 48 c7 c0 c0 30 87 8e 48 85 c0 0f 84 00 fe ff ff be 04 00 00 00 48 89 c7 e8 fb ab 07 00 65 49 ff 44 24 08 e9 e8 fd ff ff <e8> ab 5e 08 00 84 c0 0f 85 f9 fd ff ff 48 8d 3d fc c8 f9 0e 67 48
RSP: 0018:ffffc9000350f4a0 EFLAGS: 00000297
RAX: 0000000000000000 RBX: ffffffff8e7e5460 RCX: ffffffff91f09f01
RDX: 0000000000000000 RSI: ffffffff81b8a1ae RDI: ffffffff8e7e5460
RBP: ffffffff81b8a1ae R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000200 R11: 000000000006fcdf R12: ffffc9000350f5a8
R13: ffffc9000350f558 R14: ffffc9000350f958 R15: ffffc9000350f58c
rcu_lock_release include/linux/rcupdate.h:310 [inline]
rcu_read_unlock include/linux/rcupdate.h:869 [inline]
class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
unwind_next_frame+0x3c3/0x2090 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
save_stack+0x162/0x1e0 mm/page_owner.c:165
__reset_page_owner+0x84/0x190 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1394 [inline]
__free_frozen_pages+0x747/0x1040 mm/page_alloc.c:2935
vfree mm/vmalloc.c:3472 [inline]
vfree+0x15f/0x8d0 mm/vmalloc.c:3436
vb2_vmalloc_put drivers/media/common/videobuf2/videobuf2-vmalloc.c:68 [inline]
vb2_vmalloc_put+0x80/0xc0 drivers/media/common/videobuf2/videobuf2-vmalloc.c:63
__vb2_buf_mem_free+0x121/0x240 drivers/media/common/videobuf2/videobuf2-core.c:275
__vb2_free_mem drivers/media/common/videobuf2/videobuf2-core.c:571 [inline]
__vb2_queue_free+0x7ec/0xa30 drivers/media/common/videobuf2/videobuf2-core.c:599
vb2_core_queue_release+0x70/0x190 drivers/media/common/videobuf2/videobuf2-core.c:2679
v4l2_m2m_ctx_release+0x1e/0x40 drivers/media/v4l2-core/v4l2-mem2mem.c:1285
vicodec_release+0xa0/0x160 drivers/media/test-drivers/vicodec/vicodec-core.c:1947
v4l2_release+0x1cf/0x390 drivers/media/v4l2-core/v4l2-dev.c:468
__fput+0x3ff/0xb50 fs/file_table.c:510
task_work_run+0x150/0x240 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x8d2/0x2a60 kernel/exit.c:975
do_group_exit+0xd5/0x2a0 kernel/exit.c:1117
get_signal+0x1ec7/0x21e0 kernel/signal.c:3037
arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
do_syscall_64+0x706/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9d36d9c819
RSP: 002b:00007f9d34fd5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f9d37016090 RCX: 00007f9d36d9c819
RDX: 0000200000000080 RSI: 0000000040045612 RDI: 000000000000000a
RBP: 00007f9d36e32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9d37016128 R14: 00007f9d37016090 R15: 00007fff502c1898
</TASK>
rcu: rcu_preempt kthread starved for 7361 jiffies! g33593 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:27752 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5387 [inline]
__schedule+0x10e9/0x6820 kernel/sched/core.c:7188
__schedule_loop kernel/sched/core.c:7267 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7282
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: e6 88 02 e9 83 42 03 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 23 b0 13 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197df0 EFLAGS: 00000242
RAX: 0000000002d329c7 RBX: ffff88801e6a2500 RCX: ffffffff8b97e045
RDX: 0000000000000000 RSI: ffffffff8df5460f RDI: ffffffff8c1c1380
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed10170a67ad
R10: ffff8880b8533d6b R11: 0000000000000000 R12: 0000000000000001
R13: ffffed1003cd44a0 R14: 0000000000000001 R15: ffffffff90dbbe50
FS: 0000000000000000(0000) GS:ffff8881243ef000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fffc3075dfc CR3: 00000000360c3000 CR4: 00000000003526f0
Call Trace:
<TASK>
arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
default_idle+0x9/0x10 arch/x86/kernel/process.c:767
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x464/0x590 kernel/sched/idle.c:352
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:451
start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x148
</TASK>
net_ratelimit: 17221 callbacks suppressed
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:d6:15:86:bb:bc:d9, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:d6:15:86:bb:bc:d9, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
net_ratelimit: 21072 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:d6:15:86:bb:bc:d9, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:d6:15:86:bb:bc:d9, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
* Struck through repros no longer work on HEAD.