INFO: rcu detected stall in do_vmi_munmap (2)

Status: upstream: reported on 2025/10/19 13:51
Reported-by: syzbot+463b5f1343c74e3819d3@syzkaller.appspotmail.com
First crash: 292d, last: 9d16h
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in do_vmi_munmap 1 1 414d 414d 0/2 auto-obsoleted due to no activity on 2025/09/27 01:25
upstream INFO: rcu detected stall in do_vmi_munmap (2) mm 1 40 701d 718d 28/29 fixed on 2024/10/22 11:57
upstream INFO: rcu detected stall in do_vmi_munmap mm 1 17 953d 1181d 0/29 auto-obsoleted due to no activity on 2024/03/27 03:06

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P356/1:b..l P5769/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=194349, q=268 ncpus=2)
task:syz-executor    state:R  running task     stack:21352 pid:5769  ppid:5765   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6868
 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6892
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 copy_pte_range mm/memory.c:1107 [inline]
 copy_pmd_range mm/memory.c:1168 [inline]
 copy_pud_range mm/memory.c:1205 [inline]
 copy_p4d_range mm/memory.c:1229 [inline]
 copy_page_range+0x2be5/0x3700 mm/memory.c:1323
 dup_mmap kernel/fork.c:769 [inline]
 dup_mm kernel/fork.c:1699 [inline]
 copy_mm+0x1751/0x1e30 kernel/fork.c:1748
 copy_process+0x16c9/0x3da0 kernel/fork.c:2509
 kernel_clone+0x24b/0x8a0 kernel/fork.c:2918
 __do_sys_clone kernel/fork.c:3061 [inline]
 __se_sys_clone kernel/fork.c:3045 [inline]
 __x64_sys_clone+0x1b7/0x230 kernel/fork.c:3045
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f26241c6912
RSP: 002b:00007ffc82980ef0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffc82980ef0 RCX: 00007f26241c6912
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffc8298107c R08: 0000000000000000 R09: 0000000000000001
R10: 00005555801427d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 000000000017ee1a R15: 00007ffc829810d0
 </TASK>
task:cmp             state:R  running task     stack:24360 pid:356   ppid:316    flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:ma_slots lib/maple_tree.c:787 [inline]
RIP: 0010:mas_get_slot lib/maple_tree.c:6690 [inline]
RIP: 0010:mas_validate_gaps lib/maple_tree.c:6959 [inline]
RIP: 0010:mt_validate+0x247b/0x4410 lib/maple_tree.c:7234
Code: eb 1a 0d f7 b8 80 00 00 00 eb 5a 48 c7 c6 90 3c 74 8e e8 98 1f 0d f7 45 85 f6 0f 84 7f 01 00 00 41 83 fe 02 0f 84 69 01 00 00 <41> 83 fe 01 0f 85 77 01 00 00 e8 b6 1a 0d f7 b8 80 00 00 00 e9 72
RSP: 0018:ffffc9000beff3c0 EFLAGS: 00000297
RAX: 0000000000000003 RBX: ffff88804a47a640 RCX: 0000000000000005
RDX: ffffffff8a7a59f8 RSI: ffffffff8e743c90 RDI: 0000000000000001
RBP: ffffc9000beff570 R08: ffff88802bc13c00 R09: 0000000000000003
R10: 0000000000000002 R11: 0000000000000000 R12: ffff88804a47a600
R13: 00007f2c0217ffff R14: 0000000000000001 R15: 0000000000000000
 validate_mm+0xc6/0x450 mm/mmap.c:288
 __split_vma+0xa9e/0xc20 mm/mmap.c:2425
 do_vmi_align_munmap+0x3a3/0x16a0 mm/mmap.c:2514
 do_vmi_munmap+0x252/0x2d0 mm/mmap.c:2660
 __mmap_region mm/mmap.c:2710 [inline]
 mmap_region+0x8d9/0x2090 mm/mmap.c:2941
 do_mmap+0x98f/0x10a0 mm/mmap.c:1385
 vm_mmap_pgoff+0x1c4/0x3f0 mm/util.c:556
 ksys_mmap_pgoff+0x4c9/0x720 mm/mmap.c:1431
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f2c02256242
RSP: 002b:00007ffead2eaf78 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f2c01f7c000 RCX: 00007f2c02256242
RDX: 0000000000000001 RSI: 0000000000001000 RDI: 00007f2c01f7c000
RBP: 0000000000000812 R08: 0000000000000003 R09: 0000000000004000
R10: 0000000000000812 R11: 0000000000000206 R12: 00007ffead2eb000
R13: 00007f2c02233050 R14: 00007ffead2eb3b0 R15: 00000fffd5a5d5f2
 </TASK>
rcu: rcu_preempt kthread starved for 10563 jiffies! g194349 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27400 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 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:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: 5e 1c 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d a3 6a 3b 00 fb f4 <c3> 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2c 89 cb 80 f9
RSP: 0018:ffffc90000187de0 EFLAGS: 000002c2
RAX: 2dd85ece1be52300 RBX: ffffffff81630d44 RCX: 2dd85ece1be52300
RDX: 0000000000000001 RSI: ffffffff8acacbe0 RDI: ffffffff8b1d0660
RBP: ffffc90000187f20 R08: ffff8880b8f36bab R09: 1ffff110171e6d75
R10: dffffc0000000000 R11: ffffed10171e6d76 R12: 1ffff92000030fc8
R13: dffffc0000000000 R14: 1ffff110034c9780 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2fe18ff8 CR3: 0000000060d18000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:753
 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:178 [inline]
 do_idle+0x334/0x5c0 kernel/sched/idle.c:302
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401
 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323
 secondary_startup_64_no_verify+0x179/0x17b
 </TASK>

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/29 05:26 linux-6.6.y c5596480c50e 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in do_vmi_munmap
2026/07/27 09:36 linux-6.6.y c5596480c50e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in do_vmi_munmap
2026/07/16 01:53 linux-6.6.y da47cbc25466 27a8bd60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in do_vmi_munmap
2026/06/05 15:33 linux-6.6.y 924b4a879cbb 48b6c3fa .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in do_vmi_munmap
2026/04/21 10:44 linux-6.6.y 9760bf04666d 3f2e655b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in do_vmi_munmap
2026/01/31 09:48 linux-6.6.y 2cf6f68313dc c75a2f6e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in do_vmi_munmap
2025/12/26 15:33 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in do_vmi_munmap
2025/12/06 16:10 linux-6.6.y 4791134e4aeb d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in do_vmi_munmap
2025/11/05 16:52 linux-6.6.y 0a805b6ea8cd a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in do_vmi_munmap
2025/11/05 14:34 linux-6.6.y 0a805b6ea8cd a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in do_vmi_munmap
2025/10/19 13:50 linux-6.6.y 0bbbd97a442d 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in do_vmi_munmap
* Struck through repros no longer work on HEAD.