syzbot


INFO: rcu detected stall in devkmsg_write

Status: auto-obsoleted due to no activity on 2025/05/21 09:31
Subsystems: fs
[Documentation on labels]
First crash: 213d, last: 167d

Sample crash report:
bridge0: received packet on veth0_to_bridge with own address as source address (addr:8a:2d:99:39:72:73, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P11880/1:b..l P11893/1:b..l P11894/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=54113, q=1206 ncpus=2)
task:modprobe        state:R  running task     stack:22736 pid:11894 tgid:11894 ppid:5924   task_flags:0x400000 flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6765
 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6944
 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6968
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 do_anonymous_page mm/memory.c:4947 [inline]
 do_pte_missing mm/memory.c:4056 [inline]
 handle_pte_fault mm/memory.c:5900 [inline]
 __handle_mm_fault+0x5ca8/0x70f0 mm/memory.c:6043
 handle_mm_fault+0x3e5/0x8d0 mm/memory.c:6212
 do_user_addr_fault arch/x86/mm/fault.c:1337 [inline]
 handle_page_fault arch/x86/mm/fault.c:1480 [inline]
 exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1538
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f16e01edd1c
RSP: 002b:00007ffe8b4864b0 EFLAGS: 00010202
RAX: 0000000000021001 RBX: 0000000000000000 RCX: 0000559cbefc1000
RDX: 0000559cbefa0000 RSI: 0000000000000000 RDI: 0000559cbefc1000
RBP: 00007f16e0317aa0 R08: 0000000000000000 R09: 00007f16e0317d80
R10: 0000000000000037 R11: 0000000000000206 R12: 00007f16e0317b00
R13: 0000000000000290 R14: 0000000000000000 R15: 0000559cbefa0000
 </TASK>
task:syz.9.1425      state:R  running task     stack:26448 pid:11893 tgid:11886 ppid:10931  task_flags:0x40054c flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6765
 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6944
 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6968
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
 __local_bh_enable_ip+0x179/0x200 kernel/softirq.c:396
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 nl80211_netlink_notify+0x6e6/0x840 net/wireless/nl80211.c:20253
 notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
 blocking_notifier_call_chain+0x69/0x90 kernel/notifier.c:380
 netlink_release+0x11cd/0x1bf0 net/netlink/af_netlink.c:764
 __sock_release net/socket.c:647 [inline]
 sock_close+0xbc/0x240 net/socket.c:1398
 __fput+0x3e9/0x9f0 fs/file_table.c:464
 task_work_run+0x24f/0x310 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0xa2a/0x28e0 kernel/exit.c:938
 do_group_exit+0x207/0x2c0 kernel/exit.c:1087
 get_signal+0x168c/0x1720 kernel/signal.c:3036
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa82218ec7c
RSP: 002b:00007fa81ffd3ec0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: 000000000000001c RBX: 00007fa81ffd3fc0 RCX: 00007fa82218ec7c
RDX: 000000000000001c RSI: 00007fa81ffd4010 RDI: 0000000000000006
RBP: 0000000000000000 R08: 00007fa81ffd3f14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000006
R13: 00007fa81ffd3f68 R14: 00007fa81ffd4010 R15: 0000000000000000
 </TASK>
task:syz.4.1424      state:R  running task     stack:22848 pid:11880 tgid:11880 ppid:10190  task_flags:0x40044c flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6765
 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6944
 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6968
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
 unwind_next_frame+0x18f8/0x22d0 arch/x86/kernel/unwind_orc.c:672
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
 save_stack+0xfb/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x76/0x430 mm/page_owner.c:297
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2660
 discard_slab mm/slub.c:2684 [inline]
 __put_partials+0x160/0x1c0 mm/slub.c:3153
 put_cpu_partial+0x17c/0x250 mm/slub.c:3228
 __slab_free+0x290/0x380 mm/slub.c:4479
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4115 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4171
 taskstats_tgid_alloc kernel/taskstats.c:576 [inline]
 taskstats_exit+0x360/0xa60 kernel/taskstats.c:615
 do_exit+0x9a8/0x28e0 kernel/exit.c:923
 do_group_exit+0x207/0x2c0 kernel/exit.c:1087
 get_signal+0x168c/0x1720 kernel/signal.c:3036
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3ed538cde9
RSP: 002b:00007f3ed56cfb88 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffff92 RBX: 00000000000549be RCX: 00007f3ed538cde9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3ed55a616c
RBP: 0000000000000032 R08: 7fffffffffffffff R09: 0000001cd56cfe7f
R10: 00007f3ed56cfc80 R11: 0000000000000246 R12: 00007f3ed55a616c
R13: 00007f3ed56cfc80 R14: 00000000000549f0 R15: 00007f3ed56cfca0
 </TASK>
rcu: rcu_preempt kthread starved for 8304 jiffies! g54113 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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:25624 pid:17    tgid:17    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5205 Comm: udevd Not tainted 6.14.0-rc3-syzkaller-00079-g87a132e73910 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:__lock_acquire+0x45e/0x2100 kernel/locking/lockdep.c:5171
Code: 83 e1 01 c1 e1 12 c1 e0 14 31 d2 83 7c 24 28 00 0f 95 c2 c1 e2 13 c1 e5 15 09 d5 09 c5 09 cd 09 dd 48 8b 44 24 18 0f b6 04 30 <84> c0 0f 85 c9 13 00 00 44 8b bc 24 e0 00 00 00 48 8b 44 24 10 89
RSP: 0018:ffffc90000006630 EFLAGS: 00000006
RAX: 0000000000000000 RBX: 0000000000022021 RCX: 0000000000000000
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffff88807503c6f0
RBP: 0000000000022021 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff2079cef R12: ffff88807503c6d4
R13: 000000000000000f R14: 0000000000000021 R15: ffffffff8eb38f60
FS:  00007f9c61f19c80(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4b699762d8 CR3: 000000007520c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 net_generic+0x3c/0x240 include/net/netns/generic.h:45
 is_vlan_ip net/bridge/br_netfilter_hooks.c:93 [inline]
 br_nf_post_routing+0x2f0/0xe80 net/bridge/br_netfilter_hooks.c:949
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:269 [inline]
 NF_HOOK+0x2a7/0x460 include/linux/netfilter.h:312
 br_forward_finish+0xd8/0x130 net/bridge/br_forward.c:66
 br_nf_forward_finish+0xb49/0xfb0 net/bridge/br_netfilter_hooks.c:665
 NF_HOOK+0x700/0x7c0 include/linux/netfilter.h:314
 br_nf_forward_ip+0x61e/0x7b0 net/bridge/br_netfilter_hooks.c:719
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:269 [inline]
 NF_HOOK+0x2a7/0x460 include/linux/netfilter.h:312
 __br_forward+0x489/0x660 net/bridge/br_forward.c:115
 br_handle_frame_finish+0x18d2/0x2000 net/bridge/br_input.c:220
 br_nf_hook_thresh+0x472/0x590
 br_nf_pre_routing_finish_ipv6+0xaa0/0xdd0
 NF_HOOK include/linux/netfilter.h:314 [inline]
 br_nf_pre_routing_ipv6+0x379/0x770 net/bridge/br_netfilter_ipv6.c:184
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:282 [inline]
 br_handle_frame+0x9f3/0x1530 net/bridge/br_input.c:433
 __netif_receive_skb_core+0x13e7/0x4540 net/core/dev.c:5722
 __netif_receive_skb_one_core net/core/dev.c:5826 [inline]
 __netif_receive_skb+0x12f/0x650 net/core/dev.c:5941
 process_backlog+0x662/0x15b0 net/core/dev.c:6289
 __napi_poll+0xcb/0x490 net/core/dev.c:7106
 napi_poll net/core/dev.c:7175 [inline]
 net_rx_action+0x89b/0x1240 net/core/dev.c:7297
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
 __do_softirq kernel/softirq.c:595 [inline]
 invoke_softirq kernel/softirq.c:435 [inline]
 __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2061 [inline]
RIP: 0010:vprintk_emit+0x700/0xa10 kernel/printk/printk.c:2431
Code: 00 e8 c4 31 21 00 4c 8d bc 24 a0 00 00 00 4d 85 e4 75 07 e8 b2 31 21 00 eb 06 e8 ab 31 21 00 fb 49 bc 00 00 00 00 00 fc ff df <48> c7 c7 20 4b a1 8e 31 f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00
RSP: 0018:ffffc900031977e0 EFLAGS: 00000293
RAX: ffffffff81a088e5 RBX: 0000000000000000 RCX: ffff88807503bc00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900031978f0 R08: ffffffff81a088be R09: 1ffffffff2079cee
R10: dffffc0000000000 R11: fffffbfff2079cef R12: dffffc0000000000
R13: 1ffff92000632f00 R14: ffffffff81a08720 R15: ffffc90003197880
 devkmsg_emit+0xda/0x120 kernel/printk/printk.c:755
 devkmsg_write+0x31d/0x3e0 kernel/printk/printk.c:818
 do_iter_readv_writev+0x71a/0x9d0
 vfs_writev+0x38b/0xbc0 fs/read_write.c:1050
 do_writev+0x1b6/0x360 fs/read_write.c:1096
 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
RIP: 0033:0x7f9c61b1ae03
Code: 89 c7 48 89 44 24 08 e8 6a f2 f9 ff 48 8b 44 24 08 48 83 c4 28 c3 c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 14 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 6d 48 8b 15 f6 5f 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffc5552a7b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9c61b1ae03
RDX: 0000000000000005 RSI: 00007ffc5552a820 RDI: 0000000000000005
RBP: 00007ffc5552a820 R08: 00007ffc5552a897 R09: 00007ffc5552a138
R10: 0000000000000002 R11: 0000000000000246 R12: 000000000000001c
R13: 00007ffc5552a948 R14: 0000000000000000 R15: 00007ffc5552a8a8
 </TASK>
net_ratelimit: 17289 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:1b, 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:0c, 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 veth0_to_bridge with own address as source address (addr:9a:e8:5e:fb:c0:a0, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:8a:2d:99:39:72:73, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
net_ratelimit: 23640 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 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:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:9a:e8:5e:fb:c0:a0, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:8a:2d:99:39:72:73, 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 veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, 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 bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/20 09:21 upstream 87a132e73910 50668798 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in devkmsg_write
2025/01/05 07:58 upstream ab75170520d4 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in devkmsg_write
* Struck through repros no longer work on HEAD.