INFO: rcu detected stall in sys_rt

Date	Name	Commit	Repro	Result
2025/10/11	linux-6.6.y (ToT)	e617101e5626	C	[report] INFO: rcu detected stall in sys_newfstat
2025/10/11	upstream (ToT)	0739473694c4	C	Didn't crash

Date

Name

Commit

Repro

Result

2025/10/11

linux-6.6.y (ToT)

e617101e5626

[report] INFO: rcu detected stall in sys_newfstat

2025/10/11

upstream (ToT)

0739473694c4

Didn't crash

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-6.1	INFO: rcu detected stall in sys_rt_sigreturn origin:lts-only	1	syz		error	2	62d	63d	0/3	upstream: reported syz repro on 2025/09/16 12:37
linux-5.15	INFO: rcu detected stall in sys_rt_sigreturn missing-backport origin:lts-only	1	C		done	113	8d02h	596d	0/3	upstream: reported C repro on 2024/04/01 14:20

Created	Duration	User	Patch	Repo	Result
2025/11/11 19:19	2h38m	bisect fix		linux-6.6.y	OK (0) job log log

Created

Duration

User

Patch

Repo

Result

2025/11/11 19:19

2h38m

bisect fix

linux-6.6.y

OK (0) job log log

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6018/1:b..l rcu: (detected by 1, t=10502 jiffies, g=16561, q=679 ncpus=2) task:syz-executor state:R running task stack:21736 pid:6018 ppid:6008 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 vprintk_emit+0x578/0x600 kernel/printk/printk.c:2342 _printk+0xd0/0x110 kernel/printk/printk.c:2366 batadv_check_known_mac_addr+0x29b/0x3e0 net/batman-adv/hard-interface.c:526 batadv_hard_if_event+0x3a3/0x15b0 net/batman-adv/hard-interface.c:998 notifier_call_chain+0x197/0x390 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:2064 [inline] call_netdevice_notifiers net/core/dev.c:2078 [inline] dev_set_mac_address+0x377/0x4b0 net/core/dev.c:8948 dev_set_mac_address_user+0x31/0x50 net/core/dev.c:8962 do_setlink+0x871/0x3fb0 net/core/rtnetlink.c:2860 __rtnl_newlink net/core/rtnetlink.c:3703 [inline] rtnl_newlink+0x175b/0x2020 net/core/rtnetlink.c:3750 rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6475 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x46a/0x620 net/socket.c:2201 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0xf0 net/socket.c:2209 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7ff705990d5c RSP: 002b:00007ffff9892640 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007ff706714620 RCX: 00007ff705990d5c RDX: 000000000000002c RSI: 00007ff706714670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffff9892694 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007ff706714670 R15: 0000000000000000 </TASK> rcu: rcu_preempt kthread starved for 10551 jiffies! g16561 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:27752 pid:17 ppid:2 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 </TASK> rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6198 Comm: syz.1.18 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:__run_hrtimer kernel/time/hrtimer.c:1779 [inline] RIP: 0010:__hrtimer_run_queues+0x69e/0xc40 kernel/time/hrtimer.c:1814 Code: ff 02 48 8b 44 24 38 42 80 3c 28 00 74 08 48 89 df e8 f6 2d 67 00 4c 39 23 75 4d e8 3c d6 0f 00 48 8b 44 24 38 42 80 3c 28 00 <74> 08 48 89 df e8 78 2e 67 00 48 c7 03 00 00 00 00 48 8b 84 24 a8 RSP: 0018:ffffc90000007ca0 EFLAGS: 00000046 RAX: 1ffff110171c5739 RBX: ffff8880b8e2b9c8 RCX: ffff888021ce3c00 RDX: 0000000000000100 RSI: 1ffff110171c5732 RDI: ffff88803128f1c0 RBP: ffffc90000007df0 R08: ffff88803128f1d7 R09: 0000000000000000 R10: ffff88803128f1c8 R11: ffffed1006251e3b R12: ffff88803128f1c0 R13: dffffc0000000000 R14: ffff8880b8e2b9d8 R15: ffff8880b8e2b980 FS: 0000555577672500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000006b000 CR3: 0000000071c0f000 CR4: 00000000003506f0 Call Trace: <IRQ> hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1831 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:135 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:178 [inline] RIP: 0010:kasan_check_range+0x277/0x290 mm/kasan/generic.c:187 Code: eb 0c 4f 8d 5c 33 05 eb 05 4f 8d 5c 33 06 4d 89 dc 4d 85 db 0f 84 56 ff ff ff 4d 01 d1 4d 39 cc 75 11 41 83 e0 07 45 0f be 09 <45> 39 c8 0f 8c 3d ff ff ff 0f b6 d2 e8 68 f2 ff ff 34 01 e9 2e ff RSP: 0018:ffffc900033f7ae8 EFLAGS: 00000206 RAX: ffffffff81314f01 RBX: ffffffffffffffff RCX: ffffffff81314fb8 RDX: 0000000000000001 RSI: 000000000000006c RDI: ffffc900033f7bc0 RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200067ef85 R12: fffff5200067ef85 R13: 00007fff7726d080 R14: fffff5200067ef86 R15: 1ffff9200067ef78 __asan_memset+0x22/0x40 mm/kasan/shadow.c:84 __fpu_restore_sig arch/x86/kernel/fpu/signal.c:340 [inline] fpu__restore_sig+0x168/0x10e0 arch/x86/kernel/fpu/signal.c:493 restore_sigcontext arch/x86/kernel/signal_64.c:95 [inline] __ia32_sys_rt_sigreturn+0x65d/0x7b0 arch/x86/kernel/signal_64.c:266 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fb426f8eec9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff7726d478 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000035856 RCX: 00007fb426f8eec9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000001 R09: 000000047726d76f R10: 0000001b33720000 R11: 0000000000000246 R12: 00007fb4271e5fac R13: 00007fb4271e5fa0 R14: ffffffffffffffff R15: 0000000000000004 </TASK> sched: RT throttling activated

Crashes (2):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2025/10/06 05:40	linux-6.6.y	f34f16e5c632	49379ee0	.config	console log	report	syz / log	C		[disk image] [vmlinux] [kernel image]	ci2-linux-6-6-kasan	INFO: rcu detected stall in sys_rt_sigreturn
2025/08/14 20:20	linux-6.6.y	3a8ababb8b6a	5d8c2ac2	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-linux-6-6-kasan	INFO: rcu detected stall in sys_rt_sigreturn

Crashes (2):

Assets (help?)