syzbot


INFO: rcu detected stall in sys_unshare (9)

Status: upstream: reported C repro on 2023/11/11 00:17
Subsystems: bpf
[Documentation on labels]
Reported-by: syzbot+872bccd9a68c6ba47718@syzkaller.appspotmail.com
First crash: 202d, last: 84d
Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: INFO: rcu detected stall in corrupted (log)
Repro: C syz .config
  
Discussions (4)
Title Replies (including bot) Last reply
[syzbot] Monthly bpf report (Mar 2024) 0 (1) 2024/03/11 10:18
[syzbot] Monthly bpf report (Jan 2024) 1 (2) 2024/01/10 00:28
[syzbot] Monthly bpf report (Dec 2023) 0 (1) 2023/12/08 13:16
[syzbot] [bpf?] INFO: rcu detected stall in sys_unshare (9) 0 (1) 2023/11/11 00:17
Similar bugs (10)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_unshare (2) kernel 1 1601d 1601d 0/26 closed as invalid on 2020/01/08 05:23
upstream INFO: rcu detected stall in sys_unshare (5) net 1 863d 863d 0/26 closed as invalid on 2022/02/08 10:10
upstream INFO: rcu detected stall in sys_unshare (3) net 1 1087d 1087d 0/26 auto-closed as invalid on 2021/09/03 04:28
linux-5.15 INFO: rcu detected stall in sys_unshare origin:upstream C 2 4d02h 6d18h 0/3 upstream: reported C repro on 2024/05/20 16:51
upstream INFO: rcu detected stall in sys_unshare (6) kernfs 1 832d 832d 0/26 auto-closed as invalid on 2022/05/15 15:21
upstream INFO: rcu detected stall in sys_unshare kernel 3 1636d 1637d 0/26 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in sys_unshare (4) kernel 1 996d 996d 0/26 auto-closed as invalid on 2021/12/03 09:38
upstream INFO: rcu detected stall in sys_unshare (7) bpf net 12 448d 580d 0/26 auto-obsoleted due to no activity on 2023/06/03 15:22
linux-6.1 INFO: rcu detected stall in sys_unshare origin:upstream C 1 3d16h 175d 0/3 upstream: reported C repro on 2023/12/04 08:29
android-5-15 BUG: soft lockup in sys_unshare 1 22d 22d 0/2 premoderation: reported on 2024/05/05 08:22
Last patch testing requests (4)
Created Duration User Patch Repo Result
2024/03/18 11:00 1h07m retest repro upstream error OK
2024/03/18 11:00 7h44m retest repro upstream error OK
2024/03/18 11:00 22m retest repro upstream error OK
2023/11/21 00:25 16m retest repro upstream report log
Fix bisection attempts (2)
Created Duration User Patch Repo Result
2024/01/07 02:12 1h35m bisect fix upstream job log (0) log
2023/12/07 20:41 3h39m bisect fix upstream job log (0) log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5074/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=5981, q=6 ncpus=2)
task:syz-executor237 state:R  running task     stack:24984 pid:5074  tgid:5074  ppid:5071   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5400 [inline]
 __schedule+0x177f/0x49a0 kernel/sched/core.c:6727
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7047
 irqentry_exit+0x5e/0x90 kernel/entry/common.c:348
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:lock_acquire+0x25a/0x530 kernel/locking/lockdep.c:5758
Code: 2b 00 74 08 4c 89 f7 e8 c4 24 81 00 f6 44 24 61 02 0f 85 8e 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc90004286ec0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff92000850de4 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: ffffffff8baac7e0 RDI: ffffffff8bfd99e0
RBP: ffffc90004287008 R08: ffffffff92c58427 R09: 1ffffffff258b084
R10: dffffc0000000000 R11: fffffbfff258b085 R12: 1ffff92000850de0
R13: dffffc0000000000 R14: ffffc90004286f20 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
 rcu_read_lock include/linux/rcupdate.h:750 [inline]
 is_bpf_text_address+0x42/0x2b0 kernel/bpf/core.c:762
 kernel_text_address+0xa7/0xe0 kernel/extable.c:125
 __kernel_text_address+0xd/0x40 kernel/extable.c:79
 unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369
 arch_stack_walk+0x124/0x1b0 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0x117/0x1d0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:312 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3813 [inline]
 slab_alloc_node mm/slub.c:3860 [inline]
 kmem_cache_alloc+0x16f/0x340 mm/slub.c:3867
 kmem_cache_zalloc include/linux/slab.h:701 [inline]
 fill_pool lib/debugobjects.c:168 [inline]
 debug_objects_fill_pool+0x7e6/0x9b0 lib/debugobjects.c:615
 __debug_object_init+0xa4/0x400 lib/debugobjects.c:627
 debug_timer_init kernel/time/timer.c:774 [inline]
 debug_init kernel/time/timer.c:822 [inline]
 init_timer_key+0x38/0x2f0 kernel/time/timer.c:866
 ipv6_add_dev+0x1c5/0x1290 net/ipv6/addrconf.c:388
 addrconf_notify+0x6a7/0x1020 net/ipv6/addrconf.c:3608
 notifier_call_chain+0x18f/0x3b0 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:2004 [inline]
 call_netdevice_notifiers net/core/dev.c:2018 [inline]
 register_netdevice+0x151f/0x19c0 net/core/dev.c:10294
 register_netdev+0x3b/0x50 net/core/dev.c:10393
 ip6_tnl_init_net+0x238/0x2f0 net/ipv6/ip6_tunnel.c:2270
 ops_init+0x352/0x610 net/core/net_namespace.c:136
 setup_net+0x4d1/0xbc0 net/core/net_namespace.c:339
 copy_net_ns+0x4e3/0x7b0 net/core/net_namespace.c:495
 create_new_namespaces+0x425/0x7b0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x122/0x180 kernel/nsproxy.c:228
 ksys_unshare+0x616/0xc00 kernel/fork.c:3428
 __do_sys_unshare kernel/fork.c:3499 [inline]
 __se_sys_unshare kernel/fork.c:3497 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:3497
 do_syscall_64+0xf9/0x240
 entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7f72abacc2f7
RSP: 002b:00007fff016181d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fff01618208 RCX: 00007f72abacc2f7
RDX: 00007f72abacae79 RSI: 00007fff01618280 RDI: 0000000040000000
RBP: 00000000000f4240 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000555556734370
R13: 0000000000000003 R14: 0000000000000003 R15: 00007fff01618240
 </TASK>
rcu: rcu_preempt kthread starved for 10564 jiffies! g5981 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:26104 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5400 [inline]
 __schedule+0x177f/0x49a0 kernel/sched/core.c:6727
 __schedule_loop kernel/sched/core.c:6802 [inline]
 schedule+0x149/0x260 kernel/sched/core.c:6817
 schedule_timeout+0x1bd/0x310 kernel/time/timer.c:2183
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:1663
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1862
 kthread+0x2ef/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:243
 </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 PID: 5095 Comm: syz-executor237 Not tainted 6.8.0-rc6-syzkaller-00278-g58c806d867bf #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:entry_SYSCALL_64+0x24/0x2d arch/x86/entry/entry_64.S:95
Code: cc cc cc cc cc cc f3 0f 1e fa 0f 01 f8 65 48 89 24 25 14 a0 00 00 66 90 0f 20 dc 0f 1f 44 00 00 48 81 e4 ff e7 ff ff 0f 22 dc <65> 48 8b 24 25 d8 be 03 00 6a 2b 65 ff 34 25 14 a0 00 00 41 53 6a
RSP: 0018:0000000023572000 EFLAGS: 00000006
RAX: 0000000000000027 RBX: 00007fff01617d70 RCX: 00007f72abac9387
RDX: 00007fff01617c40 RSI: 00007fff01617d70 RDI: 0000000000000021
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000555556734370
R13: 0000000000000004 R14: 00007fff01618250 R15: 00007fff01618240
FS:  00005555567343c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002006b000 CR3: 0000000023572000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
sched: RT throttling activated

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/04 02:30 upstream 58c806d867bf 25905f5d .config console log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in sys_unshare
2024/02/27 21:09 upstream 45ec2f5f6ed3 05e69c83 .config console log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_unshare
2023/11/07 00:07 upstream d2f51b3516da 78fae24e .config console log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_unshare
* Struck through repros no longer work on HEAD.