syzbot


INFO: rcu detected stall in sys_unshare

Status: upstream: reported C repro on 2023/12/04 08:29
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+bdc8340e3db76c2af2cc@syzkaller.appspotmail.com
First crash: 203d, last: 32d
Bug presence (1)
Date Name Commit Repro Result
2023/12/04 upstream (ToT) 33cc938e65a9 C [report] INFO: rcu detected stall in corrupted
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 1629d 1629d 0/27 closed as invalid on 2020/01/08 05:23
upstream INFO: rcu detected stall in sys_unshare (5) net 1 892d 892d 0/27 closed as invalid on 2022/02/08 10:10
upstream INFO: rcu detected stall in sys_unshare (3) net 1 1115d 1115d 0/27 auto-closed as invalid on 2021/09/03 04:28
linux-5.15 INFO: rcu detected stall in sys_unshare origin:upstream C 2 32d 35d 0/3 upstream: reported C repro on 2024/05/20 16:51
upstream INFO: rcu detected stall in sys_unshare (6) kernfs 1 861d 861d 0/27 auto-closed as invalid on 2022/05/15 15:21
upstream INFO: rcu detected stall in sys_unshare (9) bpf C inconclusive 5 7d13h 227d 0/27 upstream: reported C repro on 2023/11/11 00:17
upstream INFO: rcu detected stall in sys_unshare kernel 3 1665d 1665d 0/27 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in sys_unshare (4) kernel 1 1024d 1024d 0/27 auto-closed as invalid on 2021/12/03 09:38
upstream INFO: rcu detected stall in sys_unshare (7) bpf net 12 477d 608d 0/27 auto-obsoleted due to no activity on 2023/06/03 15:22
android-5-15 BUG: soft lockup in sys_unshare 1 50d 50d 0/2 premoderation: reported on 2024/05/05 08:22
Fix bisection attempts (5)
Created Duration User Patch Repo Result
2024/05/23 16:55 1h47m bisect fix linux-6.1.y job log (0) log
2024/04/19 07:30 2h12m bisect fix linux-6.1.y job log (0) log
2024/03/16 17:54 2h35m bisect fix linux-6.1.y job log (0) log
2024/02/11 03:30 2h01m bisect fix linux-6.1.y job log (0) log
2024/01/04 09:33 1h19m bisect fix linux-6.1.y 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): P3576/1:b..l
	(detected by 1, t=10503 jiffies, g=5981, q=21 ncpus=2)
task:syz-executor524 state:R  running task     stack:24984 pid:3576  ppid:3570   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870
 irqentry_exit+0x53/0x80 kernel/entry/common.c:433
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:packet_notifier+0x12c/0xa30 net/packet/af_packet.c:4151
Code: c2 80 15 f0 8b e8 74 04 05 f8 48 81 c3 b8 03 00 00 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 c7 4b 7c f8 4c 8b 3b <4d> 85 ff 0f 84 3b 08 00 00 49 83 c7 98 0f 84 31 08 00 00 48 8b 44
RSP: 0018:ffffc90003c3f7f8 EFLAGS: 00000246
RAX: 1ffff1100e685b0f RBX: ffff88807342d878 RCX: ffff8880767d1dc0
RDX: 0000000000000000 RSI: ffffffff8b3cf3a0 RDI: ffffffff8b3cf360
RBP: 0000000000000001 R08: ffffffff8965a382 R09: fffffbfff2091c45
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000005 R15: 0000000000000000
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xd0/0x170 kernel/notifier.c:455
 call_netdevice_notifiers_info net/core/dev.c:1970 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2008 [inline]
 call_netdevice_notifiers+0x145/0x1b0 net/core/dev.c:2022
 register_netdevice+0x12f2/0x1720 net/core/dev.c:10126
 register_netdev+0x37/0x50 net/core/dev.c:10219
 ip6gre_init_net+0x211/0x2e0 net/ipv6/ip6_gre.c:1644
 ops_init+0x356/0x600 net/core/net_namespace.c:135
 setup_net+0x4b5/0xb90 net/core/net_namespace.c:332
 copy_net_ns+0x395/0x5d0 net/core/net_namespace.c:478
 create_new_namespaces+0x425/0x7a0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x11e/0x170 kernel/nsproxy.c:226
 ksys_unshare+0x580/0xb20 kernel/fork.c:3203
 __do_sys_unshare kernel/fork.c:3274 [inline]
 __se_sys_unshare kernel/fork.c:3272 [inline]
 __x64_sys_unshare+0x34/0x40 kernel/fork.c:3272
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f22996822f7
RSP: 002b:00007ffe03626f38 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007ffe03626f68 RCX: 00007f22996822f7
RDX: 00007f2299680e79 RSI: 00007ffe03626fe0 RDI: 0000000040000000
RBP: 00000000000f4240 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000555555d7d370
R13: 0000000000000003 R14: 0000000000000003 R15: 00007ffe03626fa0
 </TASK>
rcu: rcu_preempt kthread starved for 10537 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:27032 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1935
 rcu_gp_fqs_loop+0x2d2/0x1120 kernel/rcu/tree.c:1674
 rcu_gp_kthread+0xa3/0x3a0 kernel/rcu/tree.c:1873
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 3600 Comm: syz-executor524 Not tainted 6.1.65-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
RIP: 0010:xsave_to_user_sigframe arch/x86/kernel/fpu/xstate.h:279 [inline]
RIP: 0010:copy_fpregs_to_sigframe arch/x86/kernel/fpu/signal.c:162 [inline]
RIP: 0010:copy_fpstate_to_sigframe+0x51e/0xda0 arch/x86/kernel/fpu/signal.c:231
Code: 57 00 4c 89 e3 48 c1 eb 20 4c 89 ff 4c 89 e6 31 d2 e8 56 46 00 00 0f 01 cb 4c 8b 7c 24 20 4c 89 ff 44 89 e0 89 da 48 0f ae 27 <31> c0 89 c3 0f 01 ca 48 8b 44 24 30 42 0f b6 04 28 84 c0 0f 85 c9
RSP: 0018:ffffc90003cff980 EFLAGS: 00040286
RAX: 0000000000000007 RBX: 0000000000000000 RCX: ffff888077343b80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffe03626b40
RBP: ffffc90003cffb50 R08: ffffffff8132fe70 R09: ffffed100ee68771
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000007
R13: dffffc0000000000 R14: ffff888077343b80 R15: 00007ffe03626b40
FS:  0000555555d7d3c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000140 CR3: 0000000029cfc000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 get_sigframe+0x378/0x4b0 arch/x86/kernel/signal.c:297
 __setup_rt_frame arch/x86/kernel/signal.c:472 [inline]
 setup_rt_frame arch/x86/kernel/signal.c:784 [inline]
 handle_signal arch/x86/kernel/signal.c:828 [inline]
 arch_do_signal_or_restart+0x4ef/0x1a10 arch/x86/kernel/signal.c:873
 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:168
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:297
 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f2299680e79
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe03626f38 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f2299680e79
RDX: 0000000020000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00000000000f4240 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000555555d7d370
R13: 0000000000000000 R14: 00007ffe03626fb0 R15: 00007ffe03626fa0
 </TASK>
sched: RT throttling activated

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/12/04 08:28 linux-6.1.y c6114c845984 f819d6f7 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unshare
* Struck through repros no longer work on HEAD.