syzbot


INFO: rcu detected stall in sys_pidfd_open

Status: auto-obsoleted due to no activity on 2025/11/25 13:03
Subsystems: lsm
[Documentation on labels]
First crash: 137d, last: 137d

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)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P10331/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=41305, q=9863 ncpus=1)
task:syz.1.805       state:R  running task     stack:29112 pid:10331 tgid:10324 ppid:5864   task_flags:0x400040 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
 irqentry_exit+0x36/0x90 kernel/entry/common.c:197
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_release+0x183/0x2f0 kernel/locking/lockdep.c:5893
Code: 0f c1 05 a8 b6 3e 12 83 f8 01 0f 85 1d 01 00 00 9c 58 f6 c4 02 0f 85 08 01 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 bd 74 3e 12 0f 85 58 01 00 00 48 83 c4 18 5b 41 5c 41
RSP: 0018:ffffc9000ad9f850 EFLAGS: 00000206
RAX: 16810db1dfdae700 RBX: ffffffff8e5c10a0 RCX: ffffc9000ad9f85c
RDX: 0000000000000000 RSI: ffffffff8de2760d RDI: ffffffff8c162d00
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 00000000000061b4 R12: ffffffff816ab8a4
R13: 0000000000000202 R14: ffff888030f30000 R15: 0000000000000001
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:871 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0x3f9/0x20a0 arch/x86/kernel/unwind_orc.c:479
 __unwind_start+0x45f/0x7f0 arch/x86/kernel/unwind_orc.c:758
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0x73/0x100 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:330 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:356
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4180 [inline]
 slab_alloc_node mm/slub.c:4229 [inline]
 kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4236
 lsm_file_alloc security/security.c:733 [inline]
 security_file_alloc+0x34/0x2b0 security/security.c:2888
 init_file+0x93/0x4c0 fs/file_table.c:159
 alloc_empty_file+0x73/0x1e0 fs/file_table.c:241
 dentry_open+0x46/0xd0 fs/open.c:1116
 pidfs_alloc_file+0x18f/0x290 fs/pidfs.c:1057
 pidfd_prepare+0x129/0x200 kernel/fork.c:1852
 pidfd_create kernel/pid.c:623 [inline]
 __do_sys_pidfd_open kernel/pid.c:659 [inline]
 __se_sys_pidfd_open kernel/pid.c:644 [inline]
 __x64_sys_pidfd_open+0x105/0x1a0 kernel/pid.c:644
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0c37b8ebe9
RSP: 002b:00007f0c38a6f038 EFLAGS: 00000246 ORIG_RAX: 00000000000001b2
RAX: ffffffffffffffda RBX: 00007f0c37db6180 RCX: 00007f0c37b8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 00007f0c37c11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0c37db6218 R14: 00007f0c37db6180 R15: 00007ffe878028f8
 </TASK>
rcu: rcu_preempt kthread starved for 250 jiffies! g41305 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:28728 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 9740 Comm: kworker/u11:2 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:__kasan_check_byte+0x6/0x50 mm/kasan/common.c:566
Code: 50 ff a8 01 48 0f 45 da e9 9c fe ff ff 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 41 54 <49> 89 f4 55 48 89 fd 53 e8 6d 24 00 00 89 c3 84 c0 74 0b 89 d8 5b
RSP: 0018:ffffc90000006a80 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff8e5c10a0 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff816ab581 RDI: ffffffff8e5c10a0
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000006 R11: 0000000000006033 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881246c3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7085585453 CR3: 0000000075a78000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 kasan_check_byte include/linux/kasan.h:399 [inline]
 lock_acquire kernel/locking/lockdep.c:5842 [inline]
 lock_acquire+0xfc/0x350 kernel/locking/lockdep.c:5825
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:243 [inline]
 __kasan_slab_free+0x60/0x70 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2417 [inline]
 slab_free mm/slub.c:4680 [inline]
 kmem_cache_free+0x2d1/0x4d0 mm/slub.c:4782
 kfree_skbmem+0x1a4/0x1f0 net/core/skbuff.c:1109
 __kfree_skb net/core/skbuff.c:1166 [inline]
 sk_skb_reason_drop+0x136/0x1a0 net/core/skbuff.c:1203
 kfree_skb_reason include/linux/skbuff.h:1275 [inline]
 kfree_skb include/linux/skbuff.h:1284 [inline]
 ip6_mc_input+0x774/0xeb0 net/ipv6/ip6_input.c:593
 dst_input include/net/dst.h:471 [inline]
 dst_input include/net/dst.h:469 [inline]
 ip6_rcv_finish+0x3df/0x580 net/ipv6/ip6_input.c:79
 ip_sabotage_in+0x21b/0x290 net/bridge/br_netfilter_hooks.c:993
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_slow+0xbb/0x200 net/netfilter/core.c:623
 nf_hook.constprop.0+0x422/0x750 include/linux/netfilter.h:273
 NF_HOOK include/linux/netfilter.h:316 [inline]
 ipv6_rcv+0xa4/0x650 net/ipv6/ip6_input.c:311
 __netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:5991
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6104
 netif_receive_skb_internal net/core/dev.c:6190 [inline]
 netif_receive_skb+0x137/0x7b0 net/core/dev.c:6249
 NF_HOOK include/linux/netfilter.h:318 [inline]
 NF_HOOK include/linux/netfilter.h:312 [inline]
 br_pass_frame_up+0x346/0x490 net/bridge/br_input.c:70
 br_handle_frame_finish+0xf5a/0x1ca0 net/bridge/br_input.c:227
 br_nf_hook_thresh+0x307/0x410 net/bridge/br_netfilter_hooks.c:1170
 br_nf_pre_routing_finish_ipv6+0x76a/0xfb0 net/bridge/br_netfilter_ipv6.c:154
 NF_HOOK include/linux/netfilter.h:318 [inline]
 br_nf_pre_routing_ipv6+0x3cd/0x8c0 net/bridge/br_netfilter_ipv6.c:184
 br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:508
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:283 [inline]
 br_handle_frame+0xad5/0x14b0 net/bridge/br_input.c:434
 __netif_receive_skb_core.constprop.0+0xa25/0x48c0 net/core/dev.c:5878
 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:5989
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6104
 process_backlog+0x442/0x15e0 net/core/dev.c:6456
 __napi_poll.constprop.0+0xba/0x550 net/core/dev.c:7506
 napi_poll net/core/dev.c:7569 [inline]
 net_rx_action+0xa9f/0xfe0 net/core/dev.c:7696
 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579
 do_softirq kernel/softirq.c:480 [inline]
 do_softirq+0xb2/0xf0 kernel/softirq.c:467
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:407
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 cfg80211_inform_single_bss_data+0x9ae/0x1df0 net/wireless/scan.c:2395
 cfg80211_inform_bss_data+0x224/0x3bd0 net/wireless/scan.c:3234
 cfg80211_inform_bss_frame_data+0x26f/0x750 net/wireless/scan.c:3325
 ieee80211_bss_info_update+0x310/0xab0 net/mac80211/scan.c:226
 ieee80211_rx_bss_info net/mac80211/ibss.c:1094 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1573 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x1905/0x2fd0 net/mac80211/ibss.c:1600
 ieee80211_iface_process_skb net/mac80211/iface.c:1699 [inline]
 ieee80211_iface_work+0xe2e/0x1360 net/mac80211/iface.c:1753
 cfg80211_wiphy_work+0x2c7/0x580 net/wireless/core.c:435
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
net_ratelimit: 11093 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 veth0_to_bridge with own address as source address (addr:e2:a1:e0:2c:18:e1, 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:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:e2:a1:e0:2c:18:e1, 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)
net_ratelimit: 10991 callbacks suppressed
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 veth0_to_bridge with own address as source address (addr:e2:a1:e0:2c:18:e1, 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:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:e2:a1:e0:2c:18:e1, 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:0c, vlan:0)

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/27 12:52 upstream fab1beda7597 e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in sys_pidfd_open
* Struck through repros no longer work on HEAD.