syzbot


INFO: rcu detected stall in tc_modify_qdisc (2)

Status: upstream: reported C repro on 2024/11/08 00:04
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+3e756bb26a645ac581b7@syzkaller.appspotmail.com
First crash: 190d, last: 16d
Bug presence (1)
Date Name Commit Repro Result
2024/12/15 upstream (ToT) 2d8308bf5b67 C [report] INFO: rcu detected stall in do_idle
Similar bugs (8)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in tc_modify_qdisc 3 306d 344d 0/3 auto-obsoleted due to no activity on 2024/10/23 00:42
upstream INFO: rcu detected stall in tc_modify_qdisc net C done 577 5d20h 1752d 0/28 upstream: reported C repro on 2020/07/29 05:53
linux-5.15 INFO: rcu detected stall in tc_modify_qdisc origin:lts-only C error 7 41d 276d 0/3 upstream: reported C repro on 2024/08/13 15:46
android-6-1 BUG: soft lockup in tc_modify_qdisc C done done 53 536d 567d 0/2 auto-obsoleted due to no activity on 2024/02/06 04:01
android-5-15 BUG: soft lockup in tc_modify_qdisc origin:lts C done done 254 625d 680d 0/2 auto-obsoleted due to no activity on 2023/11/09 01:01
linux-5.15 BUG: soft lockup in tc_modify_qdisc origin:upstream C error 1 714d 714d 0/3 auto-obsoleted due to no activity on 2023/09/11 01:53
linux-6.1 BUG: soft lockup in tc_modify_qdisc origin:upstream C done 1 712d 712d 3/3 fixed on 2023/07/10 11:22
android-5-10 BUG: soft lockup in tc_modify_qdisc C done done 314 626d 680d 0/2 auto-obsoleted due to no activity on 2023/11/07 07:54
Fix bisection attempts (4)
Created Duration User Patch Repo Result
2025/04/30 06:49 2h03m bisect fix linux-6.1.y OK (0) job log log
2025/03/27 23:48 2h23m bisect fix linux-6.1.y OK (0) job log log
2025/02/23 08:19 1h46m bisect fix linux-6.1.y OK (0) job log log
2025/01/24 04:14 1h42m bisect fix linux-6.1.y OK (0) job log log

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-...D } 2635 jiffies s: 701 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4255 Comm: syz-executor207 Not tainted 6.1.119-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline]
RIP: 0010:lock_acquire+0xf3/0x5a0 kernel/locking/lockdep.c:5633
Code: 0d 0f 86 e4 02 00 00 89 db 48 89 d8 48 c1 e8 06 48 8d 3c c5 a8 f7 9a 8e be 08 00 00 00 e8 a5 84 77 00 48 0f a3 1d a5 55 30 0d <73> 0d e8 96 e5 08 00 84 c0 0f 84 b9 02 00 00 48 c7 c0 74 2c 9b 8e
RSP: 0018:ffffc900001e0b60 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff816aa1fb
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e9af7a8
RBP: ffffc900001e0ca8 R08: dffffc0000000000 R09: fffffbfff1d35ef6
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff9200003c174
R13: dffffc0000000000 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007fc2353586c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001600 CR3: 000000001dbdf000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
 _raw_spin_lock_irq+0xcf/0x110 kernel/locking/spinlock.c:170
 __run_hrtimer kernel/time/hrtimer.c:1693 [inline]
 __hrtimer_run_queues+0x6d3/0xe50 kernel/time/hrtimer.c:1753
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1815
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x158/0x5b0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lockdep_unregister_key+0x562/0x600 kernel/locking/lockdep.c:6367
Code: 1f 91 48 c7 c6 c0 f2 6a 81 e8 0a b4 08 00 e8 45 c8 08 00 e9 ea fb ff ff e8 3b e1 46 09 41 f7 c7 00 02 00 00 74 d0 fb 45 84 f6 <75> cf eb e0 0f 0b 45 31 f6 e9 64 ff ff ff 0f 0b e9 a5 fe ff ff 0f
RSP: 0018:ffffc90003d56f80 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: 1ffff920007aadf8 RCX: ffffffff97353103
RDX: 0000000000000001 RSI: ffffffff8b0c0ea0 RDI: ffffffff8b5e6200
RBP: ffffc90003d57048 R08: dffffc0000000000 R09: fffffbfff223f93e
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc90003d56fc0
R13: 1ffff920007aadf4 R14: 0000000000000000 R15: 0000000000000203
 __qdisc_destroy+0x127/0x450 net/sched/sch_generic.c:1078
 taprio_attach+0x260/0x420 net/sched/sch_taprio.c:1844
 qdisc_graft+0x12e5/0x1610 net/sched/sch_api.c:1143
 tc_modify_qdisc+0xf29/0x1d70 net/sched/sch_api.c:1767
 rtnetlink_rcv_msg+0x818/0xff0 net/core/rtnetlink.c:6150
 netlink_rcv_skb+0x1cd/0x410 net/netlink/af_netlink.c:2493
 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
 netlink_unicast+0x7d8/0x970 net/netlink/af_netlink.c:1337
 netlink_sendmsg+0xa26/0xd60 net/netlink/af_netlink.c:1859
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5a5/0x8f0 net/socket.c:2519
 ___sys_sendmsg net/socket.c:2573 [inline]
 __sys_sendmsg+0x2a9/0x390 net/socket.c:2602
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc2353a8a89
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 1f 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:00007fc235358168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc2354331c8 RCX: 00007fc2353a8a89
RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000004
RBP: 00007fc2354331c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc2354331cc
R13: 000000000000000b R14: 00007fff857dfaa0 R15: 00007fff857dfb88
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/14 12:35 linux-6.1.y e4d90d63d385 7cbfbb3a .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in tc_modify_qdisc
2024/11/08 00:03 linux-6.1.y 7c15117f9468 867e44df .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in tc_modify_qdisc
* Struck through repros no longer work on HEAD.