syzbot


INFO: rcu detected stall in nsim_fib_event_work

Status: upstream: reported C repro on 2025/05/01 18:02
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+5cf89626ecd9d0007691@syzkaller.appspotmail.com
First crash: 46d, last: 6d01h
Cause bisection: failed (error log, bisect log)
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mm?] INFO: rcu detected stall in nsim_fib_event_work 0 (1) 2025/05/01 18:02
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in nsim_fib_event_work 1 326d 326d 0/3 auto-obsoleted due to no activity on 2024/09/19 04:15
linux-5.15 INFO: rcu detected stall in nsim_fib_event_work origin:upstream missing-backport syz error 3 59d 244d 0/3 upstream: reported syz repro on 2024/09/01 09:18
linux-6.1 INFO: rcu detected stall in nsim_fib_event_work (2) 1 208d 208d 0/3 auto-obsoleted due to no activity on 2025/01/14 20:10
linux-6.1 INFO: rcu detected stall in nsim_fib_event_work (3) origin:lts-only syz error 2 3d03h 48d 0/3 upstream: reported syz repro on 2025/03/16 03:46

Sample crash report:
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:12:9a:a3:e5:33:d9, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=6869, q=616 ncpus=2)
task:kworker/0:0     state:R  running task     stack:25496 pid:9     tgid:9     ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: events nsim_fib_event_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7090
 irqentry_exit+0x36/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__kasan_check_read+0x0/0x20 mm/kasan/shadow.c:30
Code: c3 cc cc cc cc 48 83 c4 60 48 c7 c7 90 22 a3 8d 5b 5d 41 5c e9 a1 c9 79 ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 48 8b 0c 24 89 f6 31 d2 e9 7f f0 ff ff 66 66 2e 0f 1f
RSP: 0018:ffffc900000e78c8 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff88801ed4d3d8 RCX: ffffffff822c44d1
RDX: ffff88801c6f4880 RSI: 0000000000000004 RDI: ffff88801ed4d3dc
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88801ed4d390
R13: ffff88801ed4d3dc R14: 0000000000000000 R15: dffffc0000000000
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
 __page_table_check_zero+0x260/0x5b0 mm/page_table_check.c:143
 page_table_check_free include/linux/page_table_check.h:41 [inline]
 free_pages_prepare mm/page_alloc.c:1263 [inline]
 __free_frozen_pages+0x704/0xff0 mm/page_alloc.c:2725
 discard_slab mm/slub.c:2730 [inline]
 __put_partials+0x16d/0x1c0 mm/slub.c:3199
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_kmalloc+0x8a/0xb0 mm/kasan/common.c:385
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 nsim_fib6_rt_nh_add+0x4a/0x290 drivers/net/netdevsim/fib.c:500
 nsim_fib6_rt_create drivers/net/netdevsim/fib.c:562 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x196a/0x2e80 drivers/net/netdevsim/fib.c:1493
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
net_ratelimit: 14203 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 veth0_to_bridge with own address as source address (addr:12:9a:a3:e5:33:d9, 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 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:12:9a:a3:e5:33:d9, 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:12:9a:a3:e5:33:d9, vlan:0)
net_ratelimit: 16086 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:12:9a:a3:e5:33:d9, 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)
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:12:9a:a3:e5:33:d9, 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 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)

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/27 17:56 upstream 5bc1018675ec c6b4fb39 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in nsim_fib_event_work
2025/03/17 22:23 upstream 4701f33a1070 ce3352cd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in nsim_fib_event_work
* Struck through repros no longer work on HEAD.