INFO: rcu detected stall in mmap_file (3)

Status: auto-obsoleted due to no activity on 2026/06/11 12:22
Reported-by: syzbot+7452a1b0698e4c564298@syzkaller.appspotmail.com
First crash: 338d, last: 167d
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in mmap_file 1 1 603d 603d 0/3 auto-obsoleted due to no activity on 2025/04/01 14:21
linux-5.15 INFO: rcu detected stall in mmap_file (4) 1 3 1d15h 65d 0/3 upstream: reported on 2026/06/14 00:35
linux-6.1 INFO: rcu detected stall in mmap_file 1 1 82d 82d 0/3 upstream: reported on 2026/05/27 21:33
linux-5.15 INFO: rcu detected stall in mmap_file (2) 1 1 449d 449d 0/3 auto-obsoleted due to no activity on 2025/09/02 23:08

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P18800/1:b..l
	(detected by 1, t=10502 jiffies, g=69829, q=1217)
task:syz.4.4191      state:R  running task     stack:24656 pid:18800 ppid: 13599 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6596
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __local_bh_enable_ip+0x147/0x1c0 kernel/softirq.c:408
 rcu_read_unlock_bh include/linux/rcupdate.h:810 [inline]
 __dev_queue_xmit+0x1c51/0x2fd0 net/core/dev.c:4328
 __bpf_tx_skb net/core/filter.c:2127 [inline]
 __bpf_redirect_no_mac net/core/filter.c:2161 [inline]
 __bpf_redirect+0x6ad/0xee0 net/core/filter.c:2184
 ____bpf_clone_redirect net/core/filter.c:2462 [inline]
 bpf_clone_redirect+0x2e2/0x470 net/core/filter.c:2425
 bpf_prog_6893982b85ceadf7+0x56/0x9b8
 bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 bpf_test_run+0x2a8/0x800 net/bpf/test_run.c:119
 bpf_prog_test_run_skb+0x9cc/0x1180 net/bpf/test_run.c:674
 bpf_prog_test_run+0x31e/0x390 kernel/bpf/syscall.c:3374
 __sys_bpf+0x5a5/0x6f0 kernel/bpf/syscall.c:4675
 __do_sys_bpf kernel/bpf/syscall.c:4761 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4759 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1cbeb2e799
RSP: 002b:00007f1cbcd67028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f1cbeda8090 RCX: 00007f1cbeb2e799
RDX: 000000000000002c RSI: 0000200000000080 RDI: 000000000000000a
RBP: 00007f1cbebc4bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1cbeda8128 R14: 00007f1cbeda8090 R15: 00007ffc65cbdda8
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10491 jiffies! g69829 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=37169
rcu: rcu_preempt kthread starved for 10492 jiffies! g69829 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:26992 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </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: 18795 Comm: syz.4.4191 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:perf_trace_buf_alloc+0x178/0x300 kernel/trace/trace_event_perf.c:420
Code: 2e 25 f8 ff 4e 8d 34 fd 00 6f 32 96 4c 89 f0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 f7 e8 f0 30 3d 00 4d 8b 3e e8 98 3b 3b 08 <89> c5 41 89 c6 bf 08 00 00 00 89 c6 e8 57 28 f8 ff 83 fd 07 0f 87
RSP: 0018:ffffc900000075c0 EFLAGS: 00000082
RAX: 0000000000000000 RBX: 0000000000000014 RCX: f11d97cf168d4500
RDX: 0000000000000100 RSI: ffffffff8a79f7e0 RDI: ffffffff8a79f7a0
RBP: 0000000000000001 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 R12: ffffffff8be30820
R13: dffffc0000000000 R14: ffffffff96326f08 R15: 0000607f46cf1000
FS:  00005555889e2500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1cbcd46d58 CR3: 00000000326a1000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 perf_trace_preemptirq_template+0x180/0x360 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 e2 f0 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc900000077c0 EFLAGS: 00000206
RAX: f11d97cf168d4500 RBX: 1ffff92000000efc RCX: f11d97cf168d4500
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f800
RBP: ffffc900000078a0 R08: ffffffff901d31c7 R09: 1ffffffff203a638
R10: dffffc0000000000 R11: fffffbfff203a639 R12: ffffffff8c322f00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 ndisc_send_skb+0xde0/0x1500 net/ipv6/ndisc.c:521
 addrconf_rs_timer+0x2d1/0x630 net/ipv6/addrconf.c:3956
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x53e/0x800 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:seqcount_lockdep_reader_access+0x144/0x190 include/linux/seqlock.h:106
Code: 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 42 41 f7 c5 00 02 00 00 74 01 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 27 00 00 00 00 43 c7 44 27 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc9000326f620 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: ffff88813fffb7c0 RCX: f11d97cf168d4500
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f800
RBP: ffffc9000326f6e0 R08: ffffffff901d30f7 R09: 1ffffffff203a61e
R10: dffffc0000000000 R11: fffffbfff203a61f R12: dffffc0000000000
R13: 0000000000000a02 R14: ffffffff81b53667 R15: 1ffff9200064dec4
 read_seqbegin include/linux/seqlock.h:897 [inline]
 zone_span_seqbegin include/linux/memory_hotplug.h:83 [inline]
 page_outside_zone_boundaries mm/page_alloc.c:580 [inline]
 bad_range+0x77/0x2d0 mm/page_alloc.c:607
 rmqueue mm/page_alloc.c:3760 [inline]
 get_page_from_freelist+0x1b9c/0x1ca0 mm/page_alloc.c:4189
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5487
 vm_area_alloc_pages mm/vmalloc.c:2876 [inline]
 __vmalloc_area_node mm/vmalloc.c:2932 [inline]
 __vmalloc_node_range+0x4b2/0x8b0 mm/vmalloc.c:3037
 vmalloc_user+0x70/0x80 mm/vmalloc.c:3173
 kcov_mmap+0x27/0x120 kernel/kcov.c:474
 call_mmap include/linux/fs.h:2178 [inline]
 mmap_file+0x5d/0xb0 mm/util.c:1092
 __mmap_region mm/mmap.c:1796 [inline]
 mmap_region+0xf88/0x1650 mm/mmap.c:2933
 do_mmap+0x819/0xe90 mm/mmap.c:1586
 vm_mmap_pgoff+0x1c1/0x2d0 mm/util.c:551
 ksys_mmap_pgoff+0x54b/0x790 mm/mmap.c:1635
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1cbeb2e502
Code: 4f 01 00 0f 1f 44 00 00 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 3b 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 6e 5b 5d c3 0f 1f 00 48 c7 c0 e8 ff ff ff 64
RSP: 002b:00007ffc65cbde58 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f1cbc925000 RCX: 00007f1cbeb2e502
RDX: 0000000000000003 RSI: 0000000000400000 RDI: 00007f1cbc925000
RBP: 0000000000000011 R08: 00000000000000db R09: 0000000000000000
R10: 0000000000000011 R11: 0000000000000206 R12: 0000000000000003
R13: 0000000000000003 R14: 0000000000000000 R15: 00007f1cbeda7fa0
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/03 12:21 linux-5.15.y 3330a8d33e08 28b83e23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in mmap_file
2025/11/29 09:18 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in mmap_file
2025/09/13 15:43 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in mmap_file
* Struck through repros no longer work on HEAD.