INFO: rcu detected stall in tcp_delack_timer (2)

Status: auto-obsoleted due to no activity on 2025/04/25 01:08
Subsystems: net
[Documentation on labels]
First crash: 577d, last: 577d
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in tcp_delack_timer net 1 1 788d 788d 0/29 auto-obsoleted due to no activity on 2024/09/26 01:39
linux-5.15 INFO: rcu detected stall in tcp_delack_timer 1 1 42d 42d 0/3 upstream: reported on 2026/07/13 17:56
android-5-15 BUG: soft lockup in tcp_delack_timer 1 1 826d 826d 0/2 auto-obsoleted due to no activity on 2024/08/19 05:24

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P7786/1:b..l
rcu: 	(detected by 1, t=10506 jiffies, g=41201, q=157 ncpus=2)
task:syz-executor    state:R  running task     stack:20528 pid:7786  tgid:7786  ppid:7780   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5377 [inline]
 __schedule+0x181a/0x4b90 kernel/sched/core.c:6764
 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6943
 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6967
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 copy_pte_range mm/memory.c:1201 [inline]
 copy_pmd_range+0x6dc8/0x77a0 mm/memory.c:1262
 copy_pud_range mm/memory.c:1299 [inline]
 copy_p4d_range mm/memory.c:1323 [inline]
 copy_page_range+0x99f/0xe90 mm/memory.c:1421
 dup_mmap kernel/fork.c:748 [inline]
 dup_mm kernel/fork.c:1688 [inline]
 copy_mm+0x1279/0x2110 kernel/fork.c:1740
 copy_process+0x1845/0x3d50 kernel/fork.c:2391
 kernel_clone+0x223/0x870 kernel/fork.c:2803
 __do_sys_clone kernel/fork.c:2946 [inline]
 __se_sys_clone kernel/fork.c:2930 [inline]
 __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2930
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f053b583593
RSP: 002b:00007fff07c21648 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f053b583593
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 00005555735017d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000cd843 R14: 00007fff07c217d0 R15: 00000000000000f0
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g41201 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=59075
rcu: rcu_preempt kthread starved for 10502 jiffies! g41201 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:25784 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5377 [inline]
 __schedule+0x181a/0x4b90 kernel/sched/core.c:6764
 __schedule_loop kernel/sched/core.c:6841 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6856
 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </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 UID: 0 PID: 12506 Comm: syz.8.1729 Not tainted 6.13.0-syzkaller-06074-g2c8d2a510c15 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:check_preemption_disabled+0x2/0x120 lib/smp_processor_id.c:13
Code: 53 5f 8c 48 c7 c6 00 54 5f 8c eb 1c 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 57 <41> 56 41 54 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24
RSP: 0018:ffffc90000007498 EFLAGS: 00000006
RAX: 0000000000010100 RBX: 0000000000000001 RCX: ffffffff81acd916
RDX: ffff888033c40000 RSI: ffffffff8c5f5400 RDI: ffffffff8c5f53c0
RBP: 0000000000000001 R08: ffffffff81acd93c R09: 1ffffffff2034bc6
R10: dffffc0000000000 R11: fffffbfff2034bc7 R12: dffffc0000000000
R13: ffff8880b862c600 R14: ffff888021f11340 R15: ffff8880b862c500
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000140 CR3: 00000000468fa000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
 rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:716
 trace_hrtimer_start include/trace/events/timer.h:222 [inline]
 debug_activate kernel/time/hrtimer.c:470 [inline]
 enqueue_hrtimer+0xa5/0x3c0 kernel/time/hrtimer.c:1075
 __run_hrtimer kernel/time/hrtimer.c:1755 [inline]
 __hrtimer_run_queues+0x6cb/0xd30 kernel/time/hrtimer.c:1802
 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1864
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1049
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:tcp_v4_send_check+0x0/0x310 net/ipv4/tcp_ipv4.c:674
Code: 80 e1 07 fe c1 38 c1 0f 8c f4 fe ff ff 4c 89 ef e8 b5 27 d0 f7 e9 e7 fe ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 41 57 41 56 41 55 41 54 53 50 49 89 f5 48 89 fd 49
RSP: 0018:ffffc90000007878 EFLAGS: 00000246
RAX: ffffffff8a5209ac RBX: ffffffff8a533d90 RCX: ffff888033c40000
RDX: 0000000000000100 RSI: ffff88807e0dd8c0 RDI: ffff888027d99980
RBP: ffffc90000007b08 R08: ffffffff8a51fac8 R09: 1ffff11004fb3358
R10: dffffc0000000000 R11: ffffed1004fb3359 R12: dffffc0000000000
R13: ffff888027d99980 R14: ffffc900000079a0 R15: ffff88807e0dd8c0
 __tcp_transmit_skb+0x2547/0x3ba0 net/ipv4/tcp_output.c:1437
 tcp_delack_timer_handler+0x35f/0x510 net/ipv4/tcp_timer.c:343
 tcp_delack_timer+0x200/0x390 net/ipv4/tcp_timer.c:374
 call_timer_fn+0x187/0x650 kernel/time/timer.c:1789
 expire_timers kernel/time/timer.c:1840 [inline]
 __run_timers kernel/time/timer.c:2414 [inline]
 __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2426
 run_timer_base kernel/time/timer.c:2435 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2445
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
 __do_softirq kernel/softirq.c:595 [inline]
 invoke_softirq kernel/softirq.c:435 [inline]
 __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x3a/0xb0 kernel/rcu/tree.c:716
Code: e8 1b ba 47 0a 89 c3 83 f8 08 73 7a 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 50 ab 2f 8e 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 fc 53 7e 00 48 c7 c3 58 79 03 00 49 03 1e 48 89
RSP: 0018:ffffc900041074d0 EFLAGS: 00000246
RAX: 1ffffffff1c5f56a RBX: 0000000000000000 RCX: ffff888033c40000
RDX: ffff888033c40000 RSI: ffffffff8c5f5400 RDI: ffffffff8c5f53c0
RBP: 0000000000000001 R08: ffffffff822eea31 R09: 1ffffffff2858308
R10: dffffc0000000000 R11: fffffbfff2858309 R12: 8000000048a23007
R13: 0000000000000000 R14: ffffffff8e2fab50 R15: dffffc0000000000
 rcu_read_lock include/linux/rcupdate.h:850 [inline]
 page_ext_get+0x5a/0x2a0 mm/page_ext.c:525
 page_table_check_clear+0x4b/0x550 mm/page_table_check.c:74
 get_and_clear_full_ptes include/linux/pgtable.h:705 [inline]
 zap_present_folio_ptes mm/memory.c:1503 [inline]
 zap_present_ptes mm/memory.c:1586 [inline]
 zap_pte_range mm/memory.c:1628 [inline]
 zap_pmd_range mm/memory.c:1754 [inline]
 zap_pud_range mm/memory.c:1783 [inline]
 zap_p4d_range mm/memory.c:1804 [inline]
 unmap_page_range+0x2c2e/0x4040 mm/memory.c:1825
 unmap_vmas+0x3cc/0x5f0 mm/memory.c:1915
 exit_mmap+0x292/0xca0 mm/mmap.c:1672
 __mmput+0x115/0x410 kernel/fork.c:1345
 exit_mm+0x220/0x310 kernel/exit.c:570
 do_exit+0x9ad/0x28e0 kernel/exit.c:925
 do_group_exit+0x207/0x2c0 kernel/exit.c:1087
 __do_sys_exit_group kernel/exit.c:1098 [inline]
 __se_sys_exit_group kernel/exit.c:1096 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1096
 x64_sys_call+0x26a8/0x26b0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe682f8cd29
Code: Unable to access opcode bytes at 0x7fe682f8ccff.
RSP: 002b:00007ffd4cd06818 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe682f8cd29
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffd4cd0686c R08: 00007ffd4cd068ff R09: 00000000000cd9ca
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000032
R13: 00000000000cd9ca R14: 00007ffd4cd068c0 R15: 00007ffd4cd068c0
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/25 00:59 upstream 2c8d2a510c15 9fbd772e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in tcp_delack_timer
* Struck through repros no longer work on HEAD.