syzbot


INFO: rcu detected stall in validate_mm (2)

Status: upstream: reported on 2025/02/03 21:26
Reported-by: syzbot+022b50cd692aa01556aa@syzkaller.appspotmail.com
First crash: 60d, last: 27d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in validate_mm (3) mm C error 34 9d03h 327d 0/28 upstream: reported C repro on 2024/05/12 09:19
upstream INFO: rcu detected stall in validate_mm (2) mm 2 515d 525d 0/28 auto-obsoleted due to no activity on 2024/02/04 15:00
linux-6.1 INFO: rcu detected stall in validate_mm 6 177d 244d 0/3 auto-obsoleted due to no activity on 2025/01/16 23:39

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9058/1:b..l
	(detected by 0, t=10502 jiffies, g=40097, q=95 ncpus=2)
task:syz.6.1192      state:R  running task     stack:27272 pid:9058  ppid:7943   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5243 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6560
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6872
 irqentry_exit+0x53/0x80 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__kasan_check_write+0x6/0x10 mm/kasan/shadow.c:37
Code: c7 c7 68 46 be 8c 4c 89 fe e8 f6 49 cd 08 31 db eb d7 cc cc 89 f6 48 8b 0c 24 31 d2 e9 d3 ec ff ff 0f 1f 00 89 f6 48 8b 0c 24 <ba> 01 00 00 00 e9 c0 ec ff ff 55 41 56 53 48 89 d3 41 89 f6 48 89
RSP: 0018:ffffc9000c4775f8 EFLAGS: 00000286
RAX: ffff888017c6ad48 RBX: 1ffff1100facb000 RCX: ffffffff8aa819cc
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff9782f180
RBP: ffffc9000c4777f0 R08: ffffffff8aa8655f R09: ffffffff8aa817f0
R10: 0000000000000002 R11: ffff8880601ad940 R12: 000000110c230000
R13: ffff88807d658008 R14: dffffc0000000000 R15: ffffc9000c477758
 instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
 atomic_inc include/linux/atomic/atomic-instrumented.h:190 [inline]
 mt_validate+0xd9c/0x5ad0 lib/maple_tree.c:7226
 validate_mm_mt+0x165/0x670 mm/mmap.c:294
 validate_mm+0x16e/0x380 mm/mmap.c:331
 mmap_region+0x1556/0x2660 mm/mmap.c:2910
 do_mmap+0x8c5/0xf60 mm/mmap.c:1424
 vm_mmap_pgoff+0x1ca/0x2d0 mm/util.c:520
 ksys_mmap_pgoff+0x4f5/0x6d0 mm/mmap.c:1470
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f69bf18d1a3
RSP: 002b:00007ffcf089e108 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 0000000000400000 RCX: 00007f69bf18d1a3
RDX: 0000000000000003 RSI: 00000000003c0000 RDI: 0000001b33960000
RBP: 0000001b33960000 R08: 0000000000000004 R09: 0000000000040000
R10: 0000000000000011 R11: 0000000000000246 R12: 0000000000000026
R13: 00000000000927c0 R14: 000000000007dcfe R15: 00007ffcf089e3f0
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10534 jiffies! g40097 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=30888
rcu: rcu_preempt kthread starved for 10535 jiffies! g40097 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:25880 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5243 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6560
 schedule+0xbf/0x180 kernel/sched/core.c:6636
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 9053 Comm: syz.5.1190 Not tainted 6.1.130-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:103 [inline]
RIP: 0010:__local_bh_enable_ip+0x16c/0x1f0 kernel/softirq.c:410
Code: 8b e8 c8 2a 5d 09 65 66 8b 05 e0 5e af 7e 66 85 c0 75 57 bf 01 00 00 00 e8 b1 48 0a 00 e8 dc 19 3d 00 fb 65 8b 05 cc 2e ae 7e <85> c0 75 05 e8 6b 52 ac ff 48 c7 44 24 20 0e 36 e0 45 49 c7 04 1c
RSP: 0018:ffffc9000ca878c0 EFLAGS: 00000282
RAX: 0000000080000000 RBX: 1ffff92001950f1c RCX: ffffffff973c0103
RDX: dffffc0000000000 RSI: ffffffff8b0c1d40 RDI: ffffffff8b5f6f80
RBP: ffffc9000ca87970 R08: ffffffff815bf0b6 R09: ffffed102802ef81
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 1ffff92001950f20 R14: ffffc9000ca87900 R15: 0000000000000200
FS:  00007fe2cf3ff6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe2cf3ddf98 CR3: 00000000284d0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 fpregs_unlock arch/x86/include/asm/fpu/api.h:80 [inline]
 copy_fpstate_to_sigframe+0x54d/0xda0 arch/x86/kernel/fpu/signal.c:233
 get_sigframe+0x378/0x4b0 arch/x86/kernel/signal.c:297
 __setup_rt_frame arch/x86/kernel/signal.c:472 [inline]
 setup_rt_frame arch/x86/kernel/signal.c:784 [inline]
 handle_signal arch/x86/kernel/signal.c:828 [inline]
 arch_do_signal_or_restart+0x4ef/0x1a10 arch/x86/kernel/signal.c:873
 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe2cf58d167
Code: ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 <0f> 05 48 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89
RSP: 002b:00007fe2cf3ff0e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007fe2cf7a5fa8 RCX: 00007fe2cf58d169
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fe2cf7a5fa8
RBP: 00007fe2cf7a5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe2cf7a5fac
R13: 0000000000000000 R14: 00007fff1a508a90 R15: 00007fff1a508b78
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/03/08 06:32 linux-6.1.y 6ae7ac5c4251 7e3bd60d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in validate_mm
2025/02/20 15:43 linux-6.1.y 0cbb5f65e52f 50668798 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in validate_mm
2025/02/03 21:26 linux-6.1.y 0cbb5f65e52f a21a8419 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in validate_mm
* Struck through repros no longer work on HEAD.