syzbot


INFO: rcu detected stall in kcov_ioctl (2)

Status: upstream: reported on 2025/05/11 07:59
Reported-by: syzbot+12a99337276c7bf42c3d@syzkaller.appspotmail.com
First crash: 68d, last: 68d
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in kcov_ioctl 1 2 375d 377d 0/3 auto-obsoleted due to no activity on 2024/10/16 15:00
upstream INFO: rcu detected stall in kcov_ioctl kernel 1 1 2054d 2054d 0/29 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in kcov_ioctl (2) mm 1 78 193d 353d 0/29 auto-obsoleted due to no activity on 2025/03/17 09:34
android-5-15 BUG: soft lockup in kcov_ioctl 1 8 425d 457d 0/2 auto-obsoleted due to no activity on 2024/08/17 12:17

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5098/1:b..l
	(detected by 0, t=10502 jiffies, g=17209, q=401 ncpus=2)
task:syz-executor    state:R  running task     stack:24352 pid:5098  ppid:4240   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__set_page_owner_handle+0xb6/0x3c0 mm/page_owner.c:168
Code: 24 10 89 de e8 cb 03 a6 ff 44 39 f3 0f 84 d8 02 00 00 48 8b 1d ab 78 c8 0a 49 8d 7c 1f 08 48 89 f8 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 da 01 00 00 4c 01 fb 8b 44 24 08 89 43 08 48 89 d8 48
RSP: 0018:ffffc90003467958 EFLAGS: 00000a06
RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000000
RDX: ffff88807b1a1dc0 RSI: 0000000000000001 RDI: ffff88801b5169e0
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff2117049
R10: fffffbfff2117049 R11: 1ffffffff2117048 R12: 0000000000000001
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88801b5169d0
 __set_page_owner+0x41/0x60 mm/page_owner.c:195
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x1a26/0x1ac0 mm/page_alloc.c:4328
 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5606
 vm_area_alloc_pages mm/vmalloc.c:2994 [inline]
 __vmalloc_area_node mm/vmalloc.c:3063 [inline]
 __vmalloc_node_range+0x959/0x1390 mm/vmalloc.c:3235
 vmalloc_user+0x70/0x80 mm/vmalloc.c:3389
 kcov_ioctl+0x54/0x640 kernel/kcov.c:713
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9cbdb8e56b
RSP: 002b:00007ffc7bbe5290 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000100000 RCX: 00007f9cbdb8e56b
RDX: 0000000000100000 RSI: ffffffff80086301 RDI: 00000000000000d7
RBP: 00007f9cbddb5f40 R08: 00000000000000da R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 9157 jiffies! g17209 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:27840 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 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: 0 Comm: swapper/0 Not tainted 6.1.138-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:736
Code: 48 89 df e8 c7 1a b9 f7 e9 4c ff ff ff e8 4d 14 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d b7 72 4d 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffffff8c607d88 EFLAGS: 000002c6
RAX: 2b629cbec4bcd100 RBX: ffffffff8a1930d7 RCX: 2b629cbec4bcd100
RDX: 0000000000000001 RSI: ffffffff8a6bfe00 RDI: ffffffff8abf0da0
RBP: ffffffff8c607ec0 R08: dffffc0000000000 R09: ffffed10171c6aee
R10: ffffed10171c6aee R11: 1ffff110171c6aed R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8c6bc680 R15: 1ffffffff1bfd086
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f5738d75f0 CR3: 000000007e0d4000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 default_idle_call+0x84/0xc0 kernel/sched/idle.c:109
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x1fc/0x570 kernel/sched/idle.c:303
 cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:401
 rest_init+0x2dc/0x300 init/main.c:733
 arch_call_rest_init+0xa/0xa init/main.c:893
 start_kernel+0x490/0x539 init/main.c:1140
 secondary_startup_64_no_verify+0xcf/0xdb
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/11 07:58 linux-6.1.y 02b72ccb5f9d 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in kcov_ioctl
* Struck through repros no longer work on HEAD.