syzbot

 sign-in | mailing list | source | docs
🐞 Open [1475]
≡ Subsystems
🐞 Fixed [6707]
🐞 Invalid [17230]
⬇ Missing Backports [217]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
Total Repo Heatmap Subsystems Heatmap
💬 Send us feedback

INFO: rcu detected stall in validate_mm (2)

Status: auto-obsoleted due to no activity on 2024/02/04 15:00
Subsystems: mm
[Documentation on labels]
First crash: 741d, last: 731d
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in validate_mm (3) mm 1 C error 38 14d 543d 0/29 upstream: reported C repro on 2024/05/12 09:19
linux-6.1 INFO: rcu detected stall in validate_mm (2) 1 19 4d06h 276d 0/3 upstream: reported on 2025/02/03 21:26
linux-6.1 INFO: rcu detected stall in validate_mm 1 6 394d 460d 0/3 auto-obsoleted due to no activity on 2025/01/16 23:39
linux-6.6 INFO: rcu detected stall in validate_mm origin:lts-only 1 C 3 4d07h 50d 0/2 upstream: reported C repro on 2025/09/17 06:23
linux-5.15 INFO: rcu detected stall in validate_mm origin:lts-only 1 syz 2 88d 136d 0/3 upstream: reported syz repro on 2025/06/23 12:02

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P20050/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=55405, q=306 ncpus=2)
task:modprobe        state:R  running task     stack:23688 pid:20050 ppid:2896   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x196c/0x4af0 kernel/sched/core.c:6695
 preempt_schedule_irq+0xfb/0x1b0 kernel/sched/core.c:7007
 irqentry_exit+0x57/0x80 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:check_kcov_mode kernel/kcov.c:173 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:236 [inline]
RIP: 0010:__sanitizer_cov_trace_cmp8+0x17/0x80 kernel/kcov.c:284
Code: 44 0a 20 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 4c 8b 04 24 65 48 8b 0d 40 99 75 7e 65 8b 05 41 99 75 7e <a9> 00 01 ff 00 74 10 a9 00 01 00 00 74 57 83 b9 04 16 00 00 00 74
RSP: 0018:ffffc900155ff758 EFLAGS: 00000293
RAX: 0000000080000000 RBX: 0000000000000001 RCX: ffff888082350000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900155ff950 R08: ffffffff8ac2d7aa R09: fffffbfff245d43c
R10: dffffc0000000000 R11: fffffbfff245d43c R12: ffff8880233b7a0c
R13: 0000000000000000 R14: ffff88807c225450 R15: 0000000000000001
 mas_validate_parent_slot lib/maple_tree.c:7025 [inline]
 mt_validate+0xa2a/0x4a60 lib/maple_tree.c:7213
 validate_mm+0xe7/0x500 mm/mmap.c:288
 mmap_region+0x1ca5/0x2280 mm/mmap.c:2890
 do_mmap+0x8d3/0xfa0 mm/mmap.c:1374
 vm_mmap_pgoff+0x1dc/0x410 mm/util.c:546
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f0dce333b74
RSP: 002b:00007fff317522d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fff31752388 RCX: 00007f0dce333b74
RDX: 0000000000000003 RSI: 0000000000001610 RDI: 00007f0dce090000
RBP: 00007fff317526b0 R08: 00000000ffffffff R09: 0000000000000000
R10: 0000000000000032 R11: 0000000000000246 R12: 00007f0dce316fc0
R13: 00007fff31752738 R14: 00007f0dce091610 R15: 00007f0dce090000
 </TASK>
rcu: rcu_preempt kthread starved for 10533 jiffies! g55405 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:26136 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x196c/0x4af0 kernel/sched/core.c:6695
 schedule+0xc3/0x180 kernel/sched/core.c:6771
 schedule_timeout+0x1bd/0x300 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x2c6/0x1010 kernel/rcu/tree.c:1613
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1812
 kthread+0x2d3/0x370 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </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 PID: 1224 Comm: aoe_tx0 Not tainted 6.6.0-rc7-syzkaller-00123-g3a568e3a961b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
RIP: 0010:check_preemption_disabled+0x4b/0x110 lib/smp_processor_id.c:55
Code: 8b 05 c1 82 37 75 a9 ff ff ff 7f 74 22 65 48 8b 04 25 28 00 00 00 48 3b 44 24 08 0f 85 c7 00 00 00 89 d8 48 83 c4 10 5b 41 5c <41> 5e 41 5f c3 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02
RSP: 0018:ffffc900001f0ac8 EFLAGS: 00000086
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff816d0594
RDX: 0000000000000000 RSI: ffffffff8b5986c0 RDI: ffffffff8b598680
RBP: ffffc900001f0c48 R08: ffffffff8e996b6f R09: 1ffffffff1d32d6d
R10: dffffc0000000000 R11: fffffbfff1d32d6e R12: 1ffff9200003e168
R13: dffffc0000000000 R14: 0000000000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb1a0fdaba8 CR3: 00000000210c2000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline]
 rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:699
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0xe3/0x520 kernel/locking/lockdep.c:5724
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x65/0x2b0 lib/debugobjects.c:783
 debug_hrtimer_deactivate kernel/time/hrtimer.c:427 [inline]
 debug_deactivate+0x1b/0x1f0 kernel/time/hrtimer.c:483
 __run_hrtimer kernel/time/hrtimer.c:1656 [inline]
 __hrtimer_run_queues+0x321/0xd10 kernel/time/hrtimer.c:1752
 hrtimer_interrupt+0x396/0x980 kernel/time/hrtimer.c:1814
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1063 [inline]
 __sysvec_apic_timer_interrupt+0x104/0x390 arch/x86/kernel/apic/apic.c:1080
 sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1074
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:1979 [inline]
RIP: 0010:vprintk_emit+0x4e6/0x720 kernel/printk/printk.c:2306
Code: 21 e3 0f 85 a6 01 00 00 e8 e7 5b 1d 00 44 8b 24 24 4d 85 ff 75 07 e8 d9 5b 1d 00 eb 06 e8 d2 5b 1d 00 fb 48 c7 c7 80 80 20 8d <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 41 56 e8 11
RSP: 0018:ffffc90005af74a0 EFLAGS: 00000293
RAX: ffffffff8170c18e RBX: 0000000000000000 RCX: ffff888020525940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8d208080
RBP: ffffc90005af7590 R08: ffffffff8170c16b R09: 1ffffffff20dc88a
R10: dffffc0000000000 R11: fffffbfff20dc88b R12: 000000000000002d
R13: dffffc0000000000 R14: ffffffff8170bfed R15: 0000000000000200
 dev_vprintk_emit+0x2ae/0x330 drivers/base/core.c:4849
 dev_printk_emit+0xdd/0x120 drivers/base/core.c:4860
 __netdev_printk+0x3e5/0x4c0 net/core/dev.c:11363
 netdev_warn+0x122/0x170 net/core/dev.c:11416
 ieee802154_subif_start_xmit+0x130/0x190 net/mac802154/tx.c:245
 __netdev_start_xmit include/linux/netdevice.h:4889 [inline]
 netdev_start_xmit include/linux/netdevice.h:4903 [inline]
 xmit_one net/core/dev.c:3573 [inline]
 dev_hard_start_xmit+0x241/0x750 net/core/dev.c:3589
 sch_direct_xmit+0x2b6/0x5f0 net/sched/sch_generic.c:342
 __dev_xmit_skb net/core/dev.c:3800 [inline]
 __dev_queue_xmit+0x193c/0x3ab0 net/core/dev.c:4335
 dev_queue_xmit include/linux/netdevice.h:3082 [inline]
 tx+0x6a/0x110 drivers/block/aoe/aoenet.c:63
 kthread+0x238/0x450 drivers/block/aoe/aoecmd.c:1229
 kthread+0x2d3/0x370 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/10/27 12:04 upstream 3a568e3a961b bf285f0c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in validate_mm
2023/11/06 14:55 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d2f51b3516da 78fae24e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: rcu detected stall in validate_mm
* Struck through repros no longer work on HEAD.