syzbot


INFO: rcu detected stall in sys_munmap (2)

Status: upstream: reported syz repro on 2025/08/22 04:15
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+8785aaf121cfb2141e0d@syzkaller.appspotmail.com
First crash: 604d, last: 1h02m
Cause bisection: failed (error log, bisect log)
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mm?] INFO: rcu detected stall in sys_munmap (2) 7 (10) 2025/08/28 03:35
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in sys_munmap 1 4 58d 142d 0/2 upstream: reported on 2025/07/12 12:20
upstream INFO: rcu detected stall in sys_munmap kasan mm 1 1 816d 816d 0/29 auto-obsoleted due to no activity on 2023/11/06 05:09
linux-5.15 INFO: rcu detected stall in sys_munmap 1 1 138d 138d 0/3 auto-obsoleted due to no activity on 2025/10/24 12:55
linux-6.1 INFO: rcu detected stall in sys_munmap (2) 1 15 6d06h 243d 0/3 upstream: reported on 2025/04/02 07:15
linux-6.1 INFO: rcu detected stall in sys_munmap 1 1 497d 497d 0/3 auto-obsoleted due to no activity on 2024/10/31 01:03
Last patch testing requests (3)
Created Duration User Patch Repo Result
2025/11/24 17:50 31m retest repro upstream OK log
2025/09/02 20:24 22m retest repro upstream report log
2025/08/28 02:20 46m liam.howlett@oracle.com git://git.infradead.org/users/jedix/linux-maple.git no_validate report log

Sample crash report:
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P15896/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=84521, q=993 ncpus=2)
task:udevd           state:R  running task     stack:25112 pid:15896 tgid:15896 ppid:5198   task_flags:0x400140 flags:0x00080001
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6929
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256
 irqentry_exit+0x36/0x90 kernel/entry/common.c:211
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0x50c/0x20a0 arch/x86/kernel/unwind_orc.c:505
Code: e8 19 f1 ff ff 48 89 c1 48 85 c0 0f 84 05 fe ff ff 48 b8 00 00 00 00 00 fc ff df 4c 8d 79 05 4c 89 fa 48 c1 ea 03 0f b6 04 02 <4c> 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 63 15 00 00 0f b6 41 05
RSP: 0018:ffffc900049af568 EFLAGS: 00000a07
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff91246090
RDX: 1ffffffff2248c12 RSI: 0000000000000000 RDI: ffffffff909cd4a0
RBP: ffffc900049af620 R08: ffffffff912460e4 R09: 0000000000000000
R10: 0000000000000000 R11: 00000000000123d4 R12: ffffc900049af628
R13: ffffc900049af5d8 R14: ffffc900049af60d R15: ffffffff91246095
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:342 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:368
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4978 [inline]
 slab_alloc_node mm/slub.c:5288 [inline]
 kmem_cache_alloc_noprof+0x250/0x6e0 mm/slub.c:5295
 mt_alloc_one lib/maple_tree.c:174 [inline]
 mas_alloc_nodes lib/maple_tree.c:1110 [inline]
 mas_wr_preallocate lib/maple_tree.c:3952 [inline]
 mas_store_gfp+0xd1e/0x1000 lib/maple_tree.c:5126
 vma_iter_clear_gfp include/linux/mm.h:950 [inline]
 do_vmi_align_munmap+0x3fc/0x7e0 mm/vma.c:1531
 do_vmi_munmap+0x204/0x3e0 mm/vma.c:1584
 __vm_munmap+0x196/0x380 mm/vma.c:3156
 __do_sys_munmap mm/mmap.c:1080 [inline]
 __se_sys_munmap mm/mmap.c:1077 [inline]
 __x64_sys_munmap+0x59/0x80 mm/mmap.c:1077
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7b96f1e097
RSP: 002b:00007ffc970d5418 EFLAGS: 00000246 ORIG_RAX: 000000000000000b
RAX: ffffffffffffffda RBX: 0000564fa85a4290 RCX: 00007f7b96f1e097
RDX: 0000564fa85a4278 RSI: 0000000000001000 RDI: 00007f7b975c1000
RBP: 0000564fa85910c0 R08: 0000000000000030 R09: 0000000000040000
R10: 0000564fa85910b0 R11: 0000000000000246 R12: 00007f7b976f07c0
R13: 00007f7b976f239c R14: 0000000000000022 R15: 0000000000000001
 </TASK>
rcu: rcu_preempt kthread starved for 9173 jiffies! g84521 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:28552 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7026
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 67 6f 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 23 74 2c 00 fb f4 <e9> 3c 0a 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6
RAX: 0000000000720011 RBX: 0000000000000001 RCX: ffffffff8b5db2a9
RDX: 0000000000000000 RSI: ffffffff8da29329 RDI: ffffffff8bf078c0
RBP: ffffed1003a5bb58 R08: 0000000000000001 R09: ffffed10170a6655
R10: ffff8880b85332ab R11: 0000000000000001 R12: 0000000000000001
R13: ffff88801d2ddac0 R14: ffffffff90824cd0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124b0d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9126d62fb3 CR3: 0000000078f8a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x38d/0x500 kernel/sched/idle.c:330
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x13e/0x148
 </TASK>
net_ratelimit: 15484 callbacks suppressed
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:ca:59:ab:32:d7:41, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:ca:59:ab:32:d7:41, vlan:0)
net_ratelimit: 15100 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:ca:59:ab:32:d7:41, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)

Crashes (30):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/24 19:47 upstream ac3fd01e4c1e bf6fe8fe .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in sys_munmap
2025/11/10 10:59 upstream e9a6fb0bcdd7 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_munmap
2025/09/11 03:28 upstream 7aac71907bde fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_munmap
2025/08/19 13:05 upstream be48bcf004f9 523f460e .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_munmap
2025/08/04 01:14 upstream 352af6a011d5 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_munmap
2025/07/25 04:36 upstream 25fae0b93d1d fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_munmap
2025/06/07 19:59 upstream 7a912d04415b 4826c28e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_munmap
2025/05/13 11:45 upstream e9565e23cd89 f6671af7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_munmap
2025/04/20 21:29 upstream ac71fabf1567 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_munmap
2025/03/02 01:12 upstream 03d38806a902 c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in sys_munmap
2025/02/05 09:09 upstream 5c8c229261f1 5896748e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_munmap
2025/01/21 02:22 upstream ffd294d346d1 6e87cfa2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_munmap
2025/01/12 23:44 upstream be548645527a 6dbc6a9b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_munmap
2024/08/14 07:06 upstream 6b0f8db921ab bde81f6f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_munmap
2024/07/14 17:55 upstream 4d145e3f830b eaeb5c15 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_munmap
2024/07/12 21:13 upstream 43db1e03c086 eaeb5c15 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_munmap
2024/06/24 00:06 upstream 7c16f0a4ed1c edc5149a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_munmap
2024/06/13 23:57 upstream 2ccbdf43d5e7 a9616ff5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in sys_munmap
2024/06/12 01:13 upstream 2ef5971ff345 c7d7d815 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_munmap
2024/06/09 09:40 upstream 061d1af7b030 82c05ab8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_munmap
2024/07/23 14:49 net cc73bbab4b1f 708c10c4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_munmap
2025/12/02 00:28 linux-next 7d31f578f323 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in sys_munmap
2025/11/29 03:36 linux-next 7d31f578f323 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in sys_munmap
2025/09/05 01:30 linux-next 4ac65880ebca d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in sys_munmap
2025/08/19 01:12 linux-next 3ac864c2d9bb 523f460e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in sys_munmap
2024/10/16 00:05 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 64f3b5a6bc49 bde2d81c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: rcu detected stall in sys_munmap
2024/07/14 12:36 linux-next 3fe121b62282 eaeb5c15 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in sys_munmap
2024/05/28 15:08 linux-next 6dc544b66971 34889ee3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in sys_munmap
2024/04/06 03:11 linux-next 8568bb2ccc27 18ea8213 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in sys_munmap
2025/07/26 13:54 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 82af5ea7c611 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: rcu detected stall in sys_munmap
* Struck through repros no longer work on HEAD.