INFO: rcu detected stall in sys_openat

Status: auto-obsoleted due to no activity on 2023/12/16 21:24
Reported-by: syzbot+b102cc19539192ba9f8a@syzkaller.appspotmail.com
First crash: 1104d, last: 1071d
▶ ▼ Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_openat exfat 1 5 2769d 2848d 0/29 closed as dup on 2018/10/27 13:02
linux-5.15 INFO: rcu detected stall in sys_openat missing-backport origin:upstream 1 syz, C done 80 1d19h 1151d 0/3 upstream: reported C repro on 2023/06/19 20:52
linux-6.6 INFO: rcu detected stall in sys_openat origin:lts-only 1 syz, C inconclusive 19 3d08h 400d 0/2 upstream: reported C repro on 2025/07/10 07:34
linux-6.1 INFO: rcu detected stall in sys_openat (2) origin:upstream 1 syz, C error 57 5d14h 884d 0/3 upstream: reported C repro on 2024/03/13 11:37
upstream INFO: rcu detected stall in sys_openat (3) prio:low mm 1 syz, C error 682 1d01h 1076d 0/29 upstream: reported C repro on 2023/09/03 11:10
upstream INFO: rcu detected stall in sys_openat (2) kernfs 1 8 1652d 1864d 0/29 closed as invalid on 2022/02/08 09:50
android-5-15 BUG: soft lockup in sys_openat (2) origin:lts 1 syz, C error 5 703d 752d 0/2 auto-obsoleted due to no activity on 2024/12/19 09:52
android-5-10 BUG: soft lockup in sys_openat 1 1 326d 326d 0/2 auto-obsoleted due to no activity on 2025/12/20 20:57
android-5-15 BUG: soft lockup in sys_openat 1 21 803d 859d 0/2 auto-obsoleted due to no activity on 2024/07/21 23:03

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9674/1:b..l P3584/2:b..l P9679/2:b..l
	(detected by 1, t=10503 jiffies, g=32617, q=49 ncpus=2)
task:syz-executor.2  state:R  running task     stack:26504 pid:9679  ppid:3595   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x132c/0x4330 kernel/sched/core.c:6554
 preempt_schedule_notrace+0xf8/0x140 kernel/sched/core.c:6816
 preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35
 rcu_is_watching+0x76/0xb0 kernel/rcu/tree.c:721
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0xfa/0x5a0 kernel/locking/lockdep.c:5632
 rcu_lock_acquire+0x20/0x30 include/linux/rcupdate.h:306
 rcu_read_lock include/linux/rcupdate.h:747 [inline]
 percpu_ref_tryget_many include/linux/percpu-refcount.h:241 [inline]
 percpu_ref_tryget+0x10/0x140 include/linux/percpu-refcount.h:266
 obj_cgroup_tryget include/linux/memcontrol.h:774 [inline]
 __get_obj_cgroup_from_memcg+0x70/0xe0 mm/memcontrol.c:3000
 get_obj_cgroup_from_current+0x149/0x250 mm/memcontrol.c:3020
 memcg_slab_pre_alloc_hook mm/slab.h:485 [inline]
 slab_pre_alloc_hook+0x90/0x2a0 mm/slab.h:715
 slab_alloc_node mm/slub.c:3318 [inline]
 __kmem_cache_alloc_node+0x47/0x260 mm/slub.c:3437
 __do_kmalloc_node mm/slab_common.c:954 [inline]
 __kmalloc_node_track_caller+0xa0/0x220 mm/slab_common.c:975
 kmalloc_reserve net/core/skbuff.c:437 [inline]
 __alloc_skb+0x130/0x620 net/core/skbuff.c:510
 alloc_skb include/linux/skbuff.h:1268 [inline]
 alloc_skb_with_frags+0xa4/0x740 net/core/skbuff.c:6148
 sock_alloc_send_pskb+0x915/0xa50 net/core/sock.c:2733
 unix_dgram_sendmsg+0x5b1/0x2050 net/unix/af_unix.c:1943
 sock_sendmsg_nosec net/socket.c:716 [inline]
 sock_sendmsg net/socket.c:736 [inline]
 ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2482
 ___sys_sendmsg net/socket.c:2536 [inline]
 __sys_sendmmsg+0x3ab/0x730 net/socket.c:2622
 __do_sys_sendmmsg net/socket.c:2651 [inline]
 __se_sys_sendmmsg net/socket.c:2648 [inline]
 __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2648
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f89c4a7cae9
RSP: 002b:00007f89c58320c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f89c4b9bf80 RCX: 00007f89c4a7cae9
RDX: 0000000000000318 RSI: 00000000200bd000 RDI: 0000000000000006
RBP: 00007f89c4ac847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f89c4b9bf80 R15: 00007ffe35e96de8
 </TASK>
task:syz-executor.0  state:R  running task     stack:19768 pid:3584  ppid:3574   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x132c/0x4330 kernel/sched/core.c:6554
 preempt_schedule_notrace+0xf8/0x140 kernel/sched/core.c:6816
 preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35
 rcu_is_watching+0x76/0xb0 kernel/rcu/tree.c:721
 rcu_read_lock include/linux/rcupdate.h:748 [inline]
 percpu_ref_tryget_many include/linux/percpu-refcount.h:241 [inline]
 percpu_ref_tryget+0x1e/0x140 include/linux/percpu-refcount.h:266
 css_tryget include/linux/cgroup.h:357 [inline]
 get_mem_cgroup_from_mm+0xd9/0x260 mm/memcontrol.c:1041
 __mem_cgroup_charge+0x12/0x80 mm/memcontrol.c:6915
 mem_cgroup_charge include/linux/memcontrol.h:667 [inline]
 wp_page_copy+0x3eb/0x17d0 mm/memory.c:3148
 handle_pte_fault mm/memory.c:5001 [inline]
 __handle_mm_fault mm/memory.c:5125 [inline]
 handle_mm_fault+0x2522/0x5330 mm/memory.c:5246
 do_user_addr_fault arch/x86/mm/fault.c:1380 [inline]
 handle_page_fault arch/x86/mm/fault.c:1471 [inline]
 exc_page_fault+0x26f/0x660 arch/x86/mm/fault.c:1527
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570
RIP: 0033:0x7f3d5d050019
RSP: 002b:00007fffb9f798d8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f3d5d079b13
RDX: 0000000000000386 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000555556a8c750 R11: 0000000000000246 R12: 0000000000000386
R13: ffffffffffffffb0 R14: 0000000000000006 R15: 0000000000000001
 </TASK>
task:modprobe        state:R  running task     stack:23880 pid:9674  ppid:51     flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x132c/0x4330 kernel/sched/core.c:6554
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6866
 irqentry_exit+0x53/0x80 kernel/entry/common.c:433
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:has_zero arch/x86/include/asm/word-at-a-time.h:49 [inline]
RIP: 0010:hash_name fs/namei.c:2172 [inline]
RIP: 0010:link_path_walk+0x33b/0xee0 fs/namei.c:2266
Code: 8b 3b 48 8b 44 24 20 4c 8b 28 4c 89 eb 48 f7 d3 4d 89 ee 48 b8 2f 2f 2f 2f 2f 2f 2f 2f 49 31 c6 48 b9 ff fe fe fe fe fe fe fe <49> 8d 44 0d 00 49 01 ce 49 09 c6 48 b8 80 80 80 80 80 80 80 80 48
RSP: 0018:ffffc90015dc77e0 EFLAGS: 00000202
RAX: 2f2f2f2f2f2f2f2f RBX: 8c9d9693d08c938b RCX: fefefefefefefeff
RDX: ffff88808f539dc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90015dc7910 R08: ffffffff81f36017 R09: fffff52002bb8f76
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 7362696c2f736c74 R14: 5c4d4643005c435b R15: ffff88801e779490
 path_openat+0x23d/0x2e60 fs/namei.c:3710
 do_filp_open+0x230/0x480 fs/namei.c:3741
 do_sys_openat2+0x13b/0x500 fs/open.c:1318
 do_sys_open fs/open.c:1334 [inline]
 __do_sys_openat fs/open.c:1350 [inline]
 __se_sys_openat fs/open.c:1345 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1345
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f4a620d5a46
RSP: 002b:00007ffc60b64fd8 EFLAGS: 00000287 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ffc60b65238 RCX: 00007f4a620d5a46
RDX: 0000000000080000 RSI: 00007ffc60b65050 RDI: 00000000ffffff9c
RBP: 00007ffc60b65040 R08: 0000000000080000 R09: 00007ffc60b65050
R10: 0000000000000000 R11: 0000000000000287 R12: 00007ffc60b65050
R13: 0000000000000005 R14: 00007ffc60b6521f R15: 00000000ffffffff
 </TASK>
rcu: rcu_preempt kthread starved for 10585 jiffies! g32617 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:26712 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x132c/0x4330 kernel/sched/core.c:6554
 schedule+0xbf/0x180 kernel/sched/core.c:6630
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1935
 rcu_gp_fqs_loop+0x2c2/0x1010 kernel/rcu/tree.c:1661
 rcu_gp_kthread+0xa3/0x3a0 kernel/rcu/tree.c:1860
 kthread+0x26e/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 9664 Comm: syz-executor.3 Not tainted 6.1.52-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:85 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x7b/0x290 mm/kasan/generic.c:189
Code: 00 00 00 00 fc ff df 4f 8d 34 1a 4c 89 f5 4c 29 cd 48 83 fd 10 7f 26 48 85 ed 0f 84 3a 01 00 00 49 f7 d2 49 01 da 41 80 39 00 <0f> 85 c4 01 00 00 49 ff c1 49 ff c2 75 ee e9 1d 01 00 00 45 89 cf
RSP: 0018:ffffc9001579faf8 EFLAGS: 00000246
RAX: ffffffff81b57a01 RBX: 1ffff92002af3f7c RCX: ffffffff81b57a33
RDX: 0000000000000001 RSI: 0000000000000020 RDI: ffffc9001579fbe0
RBP: 0000000000000004 R08: dffffc0000000000 R09: fffff52002af3f7c
R10: fffffffffffffffc R11: dffffc0000000001 R12: ffff888075a7eea8
R13: 0000000000000000 R14: fffff52002af3f80 R15: ffffc9001579fbe0
FS:  000055555635d480(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002006b000 CR3: 000000001ab9f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 memset+0x1f/0x40 mm/kasan/shadow.c:44
 rseq_get_rseq_cs kernel/rseq.c:139 [inline]
 rseq_ip_fixup kernel/rseq.c:252 [inline]
 __rseq_handle_notify_resume+0x423/0x1500 kernel/rseq.c:300
 rseq_handle_notify_resume include/linux/sched.h:2329 [inline]
 rseq_signal_deliver include/linux/sched.h:2338 [inline]
 setup_rt_frame arch/x86/kernel/signal.c:773 [inline]
 handle_signal arch/x86/kernel/signal.c:828 [inline]
 arch_do_signal_or_restart+0x27c/0x1a10 arch/x86/kernel/signal.c:873
 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:168
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:297
 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f115987cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe370bfe68 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000069feb RCX: 00007f115987cae9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f115999c12c
RBP: 0000000000000032 R08: 00007f115999c12c R09: 00007f115999c12c
R10: 00007ffe370bffa0 R11: 0000000000000246 R12: 00007f115999c12c
R13: 000000000006a01d R14: 00007ffe370bffc0 R15: 00007ffe370bffa0
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/09/07 21:23 linux-6.1.y 59b13c2b647e 72324844 .config console log report info ci2-linux-6-1-kasan INFO: rcu detected stall in sys_openat
2023/08/24 19:00 linux-6.1.y 802aacbbffe2 49be837e .config console log report info ci2-linux-6-1-kasan INFO: rcu detected stall in sys_openat
2023/08/05 20:38 linux-6.1.y 52a953d0934b 4ffcc9ef .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_openat
* Struck through repros no longer work on HEAD.