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INFO: rcu detected stall in io_uring_enter

Status: upstream: reported on 2025/11/29 18:08
Reported-by: syzbot+ef7351d16a5f8fa50d49@syzkaller.appspotmail.com
First crash: 1d00h, last: 1d00h
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in io_uring_enter fs 1 23 1400d 1527d 0/29 closed as invalid on 2022/02/08 10:00
upstream INFO: rcu detected stall in io_uring_enter (4) io-uring 1 1 331d 331d 0/29 auto-obsoleted due to no activity on 2025/04/03 10:23
upstream INFO: rcu detected stall in io_uring_enter (2) io-uring 1 1 573d 573d 0/29 auto-obsoleted due to no activity on 2024/08/04 08:24
upstream INFO: rcu detected stall in io_uring_enter (3) io-uring 1 1 448d 448d 0/29 auto-obsoleted due to no activity on 2024/12/07 05:42
upstream INFO: rcu detected stall in sys_io_uring_enter (2) io-uring 1 37 415d 436d 28/29 fixed on 2024/10/22 11:56
upstream INFO: rcu detected stall in sys_io_uring_enter bpf 1 2 1479d 1488d 0/29 closed as invalid on 2022/02/08 10:00

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6677/1:b..l P5787/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=17813, q=294 ncpus=2)
task:syz-executor    state:R  running task     stack:21160 pid:5787  ppid:5781   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692
RIP: 0010:bpf_tree_comp kernel/bpf/core.c:632 [inline]
RIP: 0010:__lt_find include/linux/rbtree_latch.h:115 [inline]
RIP: 0010:latch_tree_find include/linux/rbtree_latch.h:208 [inline]
RIP: 0010:bpf_ksym_find kernel/bpf/core.c:708 [inline]
RIP: 0010:is_bpf_text_address+0x145/0x2a0 kernel/bpf/core.c:742
Code: 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 9f 3f 4a 00 4d 8b 24 24 4c 89 e7 4c 89 f6 e8 e0 d2 f2 ff 4d 39 f4 76 0c <e8> c6 d0 f2 ff b8 10 00 00 00 eb 3f 49 8d 1c 2f 4c 8d a3 e8 fd ff
RSP: 0018:ffffc9000435f588 EFLAGS: 00000292
RAX: ffffffff8192cfb0 RBX: 0000000000000000 RCX: ffff88802a13bc00
RDX: 0000000000000000 RSI: 00007fcec679163a RDI: ffffffffa00044c0
RBP: 0000000000000000 R08: dffffc0000000000 R09: 1ffffffff21b52a0
R10: dffffc0000000000 R11: fffffbfff21b52a1 R12: ffffffffa00044c0
R13: dffffc0000000000 R14: 00007fcec679163a R15: ffffffff8dfbf8b8
 kernel_text_address+0xa0/0xd0 kernel/extable.c:125
 __kernel_text_address+0xd/0x30 kernel/extable.c:79
 unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369
 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383
 kasan_kmalloc include/linux/kasan.h:198 [inline]
 __do_kmalloc_node mm/slab_common.c:1007 [inline]
 __kmalloc_node+0xb4/0x230 mm/slab_common.c:1014
 kmalloc_node include/linux/slab.h:620 [inline]
 kvmalloc_node+0x70/0x180 mm/util.c:617
 xt_jumpstack_alloc net/netfilter/x_tables.c:1354 [inline]
 xt_replace_table+0x187/0x790 net/netfilter/x_tables.c:1393
 __do_replace+0x156/0x980 net/ipv4/netfilter/ip_tables.c:1064
 do_replace net/ipv4/netfilter/ip_tables.c:1141 [inline]
 do_ipt_set_ctl+0xa06/0xcc0 net/ipv4/netfilter/ip_tables.c:1635
 nf_setsockopt+0x263/0x280 net/netfilter/nf_sockopt.c:101
 do_sock_setsockopt+0x175/0x1a0 net/socket.c:2322
 __sys_setsockopt net/socket.c:2345 [inline]
 __do_sys_setsockopt net/socket.c:2354 [inline]
 __se_sys_setsockopt net/socket.c:2351 [inline]
 __x64_sys_setsockopt+0x184/0x200 net/socket.c:2351
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fcec679163a
RSP: 002b:00007ffee3ad36c8 EFLAGS: 00000202 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007ffee3ad3750 RCX: 00007fcec679163a
RDX: 0000000000000040 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000408 R09: 00007ffee3ad3b07
R10: 00007fcec69b8c40 R11: 0000000000000202 R12: 00007fcec69b8be0
R13: 00007ffee3ad36ec R14: 0000000000000000 R15: 00007fcec69ba020
 </TASK>
task:syz.3.218       state:R  running task     stack:25448 pid:6677  ppid:5786   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00
RSP: 0018:ffffc900033d7120 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: c73fca5240e83500
RDX: 0000000000000000 RSI: ffffffff8aaace60 RDI: ffffffff8afc6f40
RBP: ffffc900033d7230 R08: dffffc0000000000 R09: 1ffffffff21b52a0
R10: dffffc0000000000 R11: fffffbfff21b52a1 R12: 1ffff9200067ae30
R13: ffffffff8cd2fee0 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 is_bpf_text_address+0x47/0x2a0 kernel/bpf/core.c:741
 kernel_text_address+0xa0/0xd0 kernel/extable.c:125
 __kernel_text_address+0xd/0x30 kernel/extable.c:79
 unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369
 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf7/0x1f0 mm/page_owner.c:128
 __set_page_owner+0x1d/0x60 mm/page_owner.c:192
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
 prep_new_page mm/page_alloc.c:1561 [inline]
 get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
 alloc_slab_page+0x5d/0x170 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2e0 mm/slub.c:2081
 ___slab_alloc+0xc6d/0x1300 mm/slub.c:3253
 __kmem_cache_alloc_bulk mm/slub.c:3995 [inline]
 kmem_cache_alloc_bulk+0x1e6/0x5b0 mm/slub.c:4070
 __io_alloc_req_refill+0x261/0x480 io_uring/io_uring.c:1099
 io_alloc_req io_uring/io_uring.h:379 [inline]
 io_submit_sqes+0xc9e/0x1d00 io_uring/io_uring.c:2424
 __do_sys_io_uring_enter io_uring/io_uring.c:3779 [inline]
 __se_sys_io_uring_enter+0x2de/0x22e0 io_uring/io_uring.c:3714
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fcb1f98f749
RSP: 002b:00007fcb2083a038 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 00007fcb1fbe6180 RCX: 00007fcb1f98f749
RDX: 0000000000000000 RSI: 00000000000847ba RDI: 0000000000000007
RBP: 00007fcb1fa13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000000e R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcb1fbe6218 R14: 00007fcb1fbe6180 R15: 00007ffdb3425588
 </TASK>
rcu: rcu_preempt kthread starved for 10269 jiffies! g17813 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:27752 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148
Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d c3 f4 38 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56
RSP: 0018:ffffc90000187de0 EFLAGS: 000002c2
RAX: b154147c0ef85100 RBX: ffffffff8161981b RCX: b154147c0ef85100
RDX: 0000000000000001 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6f40
RBP: ffffc90000187f20 R08: ffff8880b8f36b2b R09: 1ffff110171e6d65
R10: dffffc0000000000 R11: ffffed10171e6d66 R12: ffffffff8e4a8e28
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110037ca780
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000049030 CR3: 0000000061e65000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:753
 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:170 [inline]
 do_idle+0x1eb/0x510 kernel/sched/idle.c:282
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323
 secondary_startup_64_no_verify+0x179/0x17b
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/29 18:07 linux-6.6.y 1e89a1be4fe9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in io_uring_enter
* Struck through repros no longer work on HEAD.