syzbot


INFO: rcu detected stall in clone (7)

Status: upstream: reported on 2025/03/27 03:03
Subsystems: mm
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+adf8ed0e3c4682852da1@syzkaller.appspotmail.com
First crash: 553d, last: 7d22h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
17fc2c9a-a9ad-4959-9dc0-31ba61f311ea assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ INFO: rcu detected stall in clone (7) 2026/05/19 00:28 2026/05/19 00:28 2026/05/19 01:17 9f74d39908454b73546eaf1b8211b48b66e5c0fe
93540eac-6eab-4f72-89df-5c0fd9cf6d2f repro INFO: rcu detected stall in clone (7) 2026/03/08 14:25 2026/03/08 14:25 2026/03/08 14:36 31e9c887f7dc24e04b3ca70d0d54fc34141844b0
Discussions (1)
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[syzbot] [mm?] INFO: rcu detected stall in clone (7) 0 (1) 2025/03/27 03:03
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in clone (2) kernel 1 14 1568d 1875d 0/29 closed as invalid on 2022/02/08 10:00
upstream INFO: rcu detected stall in clone (3) kernel 1 7 1389d 1488d 0/29 auto-obsoleted due to no activity on 2022/10/31 19:01
upstream INFO: rcu detected stall in clone bpf 1 2 2004d 2013d 0/29 auto-closed as invalid on 2021/02/24 09:47
upstream INFO: rcu detected stall in __do_sys_clone mm 1 1 2081d 2081d 0/29 auto-closed as invalid on 2020/11/09 15:43

Sample crash report:
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
ip6_tunnel: ip6gre1 xmit: Local address not yet configured!
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=afac/1/0x4000000000000000 softirq=76657/76659 fqs=0
rcu: 	(detected by 0, t=10506 jiffies, g=88253, q=167 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5622 Comm: syz-executor Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:lock_is_held_type+0xe2/0x140 kernel/locking/lockdep.c:5942
Code: b6 c0 48 c7 c7 44 c9 ef 8d 89 44 24 04 e8 a6 17 00 00 ba ff ff ff ff 65 0f c1 15 f1 a5 80 08 83 fa 01 8b 44 24 04 75 2d 9c 5a <80> e6 02 75 47 41 f7 c5 00 02 00 00 74 01 fb 48 83 c4 08 5b 5d 41
RSP: 0018:ffffc90000a08e48 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffff8880b85284d8 RCX: 0000000000000001
RDX: 0000000000000046 RSI: ffffffff8defc944 RDI: ffffffff8c1c3800
RBP: ffff88801bb60000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 00000000ffffffff
R13: 0000000000000046 R14: ffff88801bb60ca8 R15: 0000000000000007
FS:  0000555582e5e500(0000) GS:ffff888124470000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f82c0b456b8 CR3: 000000005cc28000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 lock_is_held include/linux/lockdep.h:249 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1896 [inline]
 __hrtimer_run_queues+0x7c3/0xa00 kernel/time/hrtimer.c:1994
 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:check_kcov_mode kernel/kcov.c:185 [inline]
RIP: 0010:write_comp_data+0x3a/0x90 kernel/kcov.c:246
Code: 65 48 8b 3d 30 68 02 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 c3 cc cc cc cc 8b 87 d4 16 00 00 85 c0 74 f1 <8b> 87 b0 16 00 00 83 f8 03 75 e6 48 8b 87 b8 16 00 00 8b bf b4 16
RSP: 0018:ffffc90003a17498 EFLAGS: 00000246
RAX: 0000000080000002 RBX: ffff888077d84fa8 RCX: ffffffff82827cff
RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff88801bb60000
RBP: 0000000000000001 R08: 0000000000000004 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: dffffc0000000000 R15: 0000000000000000
 __page_table_check_ptes_set+0x12f/0x4e0 mm/page_table_check.c:209
 page_table_check_ptes_set include/linux/page_table_check.h:83 [inline]
 set_ptes include/linux/pgtable.h:413 [inline]
 __copy_present_ptes mm/memory.c:1102 [inline]
 copy_present_ptes mm/memory.c:1181 [inline]
 copy_pte_range mm/memory.c:1304 [inline]
 copy_pmd_range mm/memory.c:1392 [inline]
 copy_pud_range mm/memory.c:1429 [inline]
 copy_p4d_range mm/memory.c:1453 [inline]
 copy_page_range+0x217a/0x5b00 mm/memory.c:1539
 dup_mmap+0xd25/0x2180 mm/mmap.c:1840
 dup_mm kernel/fork.c:1534 [inline]
 copy_mm kernel/fork.c:1586 [inline]
 copy_process+0x6c78/0x7ed0 kernel/fork.c:2264
 kernel_clone+0x12e/0x9c0 kernel/fork.c:2721
 __do_sys_clone+0xd9/0x120 kernel/fork.c:2862
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7a73fc58d2
Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffe4a2b4da0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffe4a2b4da0 RCX: 00007f7a73fc58d2
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffe4a2b4f2c R08: 0000000000000000 R09: 0000000000000001
R10: 0000555582e5e7d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 00000000000da5d0 R15: 00007ffe4a2b4f80
 </TASK>
rcu: rcu_preempt kthread starved for 10506 jiffies! g88253 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:28904 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1295/0x67a0 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7283
 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 5612 Comm: syz-executor Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x589/0x1700 kernel/smp.c:892
Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 39 83 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 63 0f 00 00 8b 45 08 31
RSP: 0018:ffffc90003a07618 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81fc1bcd
RDX: ffff8880367d0000 RSI: ffffffff81fc1ba7 RDI: ffff8880367d0000
RBP: ffff8880b8540f40 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed10170a81e9 R14: 0000000000000001 R15: ffff8880b843c5c0
FS:  000055555d8ff500(0000) GS:ffff888124370000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd87fbe8158 CR3: 000000005cf71000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
 flush_tlb_mm_range+0x45f/0x16f0 arch/x86/mm/tlb.c:1451
 dup_mmap+0x12e8/0x2180 mm/mmap.c:1905
 dup_mm kernel/fork.c:1534 [inline]
 copy_mm kernel/fork.c:1586 [inline]
 copy_process+0x6c78/0x7ed0 kernel/fork.c:2264
 kernel_clone+0x12e/0x9c0 kernel/fork.c:2721
 __do_sys_clone+0xd9/0x120 kernel/fork.c:2862
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f82bfdc58d2
Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffc649d2220 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffc649d2220 RCX: 00007f82bfdc58d2
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffc649d23ac R08: 0000000000000000 R09: 0000000000000001
R10: 000055555d8ff7d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 00000000000da5a0 R15: 00007ffc649d2400
 </TASK>

Crashes (103):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/15 19:42 upstream 70eda68668d1 9cd3beaa .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2026/05/08 21:00 upstream 81d6f7807536 0c5a8d8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2026/04/27 15:53 upstream 254f49634ee1 0f700595 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2026/04/27 04:34 upstream 20b64cf8705a 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2026/04/12 09:28 upstream e753c16cb3dd 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/04/07 22:27 upstream 3036cd0d3328 2c961e87 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/04/04 03:44 upstream 631919fb12fe 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/03/27 01:02 upstream 0138af2472df 4b3d9a38 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/03/23 09:01 upstream c369299895a5 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/03/20 12:34 upstream a1d9d8e83378 2f245add .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/03/19 15:39 upstream 8a30aeb0d1b4 bd6dcb30 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/03/19 11:04 upstream 8a30aeb0d1b4 bd6dcb30 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/03/17 07:43 upstream 2d1373e4246d c01bca74 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/03/05 11:56 upstream c107785c7e8d d20b04c8 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/03/04 18:27 upstream ecc64d2dc9ff e6b6b96b .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/03/01 07:57 upstream eb71ab2bf722 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/02/26 21:07 upstream f4d0ec0aa20d ffa54287 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/02/26 17:34 upstream f4d0ec0aa20d ffa54287 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/02/23 08:58 upstream 6de23f81a5e0 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/02/22 14:09 upstream 32a92f8c8932 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/02/21 13:40 upstream a95f71ad3e2e 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/02/21 02:26 upstream a95f71ad3e2e 741f5161 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/01/29 03:17 upstream 8dfce8991b95 0adc945e .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/01/25 21:31 upstream 023777797472 02bac031 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/01/20 19:54 upstream c03e9c42ae8f d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/01/14 23:08 upstream c537e12daeec d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2026/01/14 09:02 upstream c537e12daeec d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/01/14 07:21 upstream b54345928fa1 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2026/01/14 00:55 upstream b54345928fa1 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/01/12 16:19 upstream 0f61b1860cc3 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2026/01/09 12:19 upstream 623fb9912f6a d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/01/08 09:30 upstream f0b9d8eb98df d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2026/01/06 00:53 upstream 7f98ab9da046 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2026/01/05 08:30 upstream 54e82e93ca93 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2025/12/31 07:13 upstream dbf8fe85a16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2025/12/30 08:05 upstream 8640b74557fc d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2025/12/28 03:50 upstream d26143bb38e2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2025/12/27 21:49 upstream c53f467229a7 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2025/12/23 19:14 upstream b927546677c8 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2025/12/20 12:47 upstream dd9b004b7ff3 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2025/12/18 16:19 upstream ea1013c15392 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2025/12/17 16:45 upstream ea1013c15392 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2025/12/17 04:09 upstream 40fbbd64bba6 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2025/11/30 17:44 upstream e69c7c175115 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2025/11/27 04:11 upstream 4941a17751c9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2025/11/22 07:48 upstream 2eba5e05d9bc 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in clone
2025/03/26 17:28 upstream 2df0c02dab82 89d30d73 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2025/03/23 02:43 upstream 183601b78a9b c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2025/03/16 20:51 upstream d1275e99d1c4 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in clone
2025/01/05 03:02 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing f1a2241778d9 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: rcu detected stall in clone
* Struck through repros no longer work on HEAD.