BUG: soft lockup in lo_ioctl

Status: auto-obsoleted due to no activity on 2024/08/18 12:53
Reported-by: syzbot+0828a2568309c0b0a4f3@syzkaller.appspotmail.com
First crash: 819d, last: 797d
▶ ▼ Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream BUG: soft lockup in lo_ioctl prio:low kernfs 1 1 72d 68d 0/29 moderation: reported on 2026/05/20 06:47
upstream INFO: rcu detected stall in lo_ioctl (8) mm block 1 2 214d 224d 0/29 auto-obsoleted due to no activity on 2026/03/24 20:58
linux-5.15 INFO: rcu detected stall in lo_ioctl (2) 1 1 355d 355d 0/3 auto-obsoleted due to no activity on 2025/11/13 16:37
upstream INFO: rcu detected stall in lo_ioctl (4) block 1 2 1088d 1144d 0/29 auto-obsoleted due to no activity on 2023/11/02 10:53
linux-5.15 INFO: rcu detected stall in lo_ioctl 1 1 783d 783d 0/3 auto-obsoleted due to no activity on 2024/09/11 22:21
upstream INFO: rcu detected stall in lo_ioctl (3) kernfs 1 2 1671d 1676d 0/29 closed as invalid on 2022/02/08 10:00
upstream INFO: rcu detected stall in lo_ioctl (5) block 1 7 726d 815d 0/29 auto-obsoleted due to no activity on 2024/10/29 01:08
upstream INFO: rcu detected stall in lo_ioctl (7) mm 1 1 327d 327d 0/29 auto-obsoleted due to no activity on 2025/12/02 00:39
upstream INFO: rcu detected stall in lo_ioctl (6) block 1 4 528d 597d 0/29 auto-obsoleted due to no activity on 2025/05/14 17:06

Sample crash report:
watchdog: BUG: soft lockup - CPU#0 stuck for 226s! [syz-executor.2:28070]
Modules linked in:
CPU: 0 PID: 28070 Comm: syz-executor.2 Not tainted 5.15.149-syzkaller-00490-g5d96939590c0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:kvm_wait+0x147/0x180 arch/x86/kernel/kvm.c:918
Code: 4c 89 e8 48 c1 e8 03 42 0f b6 04 20 84 c0 44 8b 74 24 1c 75 34 41 0f b6 45 00 44 38 f0 75 10 66 90 0f 00 2d 5b 03 f3 03 fb f4 <e9> 24 ff ff ff fb e9 1e ff ff ff 44 89 e9 80 e1 07 38 c1 7c a3 4c
RSP: 0018:ffffc90004cfeb40 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 1ffff9200099fd6c RCX: 1ffffffff0d1aa9c
RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff8881f7037ed4
RBP: ffffc90004cfebf0 R08: dffffc0000000000 R09: ffffed103ee06fdb
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff8881f7037ed4 R14: 0000000000000001 R15: 1ffff9200099fd70
FS:  00007f5a54dd86c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5a4dd75000 CR3: 000000013a072000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 pv_wait arch/x86/include/asm/paravirt.h:597 [inline]
 pv_wait_node kernel/locking/qspinlock_paravirt.h:325 [inline]
 __pv_queued_spin_lock_slowpath+0x41b/0xc40 kernel/locking/qspinlock.c:473
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock include/linux/spinlock.h:187 [inline]
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
 _raw_spin_lock_bh+0x139/0x1b0 kernel/locking/spinlock.c:178
 sock_hash_delete_elem+0xb1/0x2f0 net/core/sock_map.c:937
 bpf_prog_2c29ac5cdc6b1842+0x3a/0x708
 bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
 __bpf_prog_run include/linux/filter.h:625 [inline]
 bpf_prog_run include/linux/filter.h:632 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1883 [inline]
 bpf_trace_run2+0xec/0x210 kernel/trace/bpf_trace.c:1920
 __bpf_trace_kfree+0x6f/0x90 include/trace/events/kmem.h:118
 trace_kfree include/trace/events/kmem.h:118 [inline]
 kfree+0x1f3/0x220 mm/slub.c:4569
 apply_wqattrs_prepare+0x621/0x10b0
 apply_workqueue_attrs_locked+0xd1/0x1e0 kernel/workqueue.c:4111
 apply_workqueue_attrs kernel/workqueue.c:4148 [inline]
 alloc_and_link_pwqs kernel/workqueue.c:4272 [inline]
 alloc_workqueue+0xcc2/0x11f0 kernel/workqueue.c:4380
 loop_configure+0x87a/0x16e0 drivers/block/loop.c:1262
 lo_ioctl+0x925/0x26f0
 blkdev_ioctl+0x2ea/0x620 block/ioctl.c:604
 block_ioctl+0xb2/0xf0 block/fops.c:493
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0x114/0x190 fs/ioctl.c:860
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:860
 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+0x61/0xcb
RIP: 0033:0x7f5a56063c4b
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007f5a54dd7e50 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f5a56063c4b
RDX: 0000000000000003 RSI: 0000000000004c00 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000005585
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007f5a54dd7f80 R14: 00007f5a54dd7f40 R15: 00007f5a4c9b8000
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 28072 Comm: syz-executor.4 Not tainted 5.15.149-syzkaller-00490-g5d96939590c0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:kvm_wait+0x147/0x180 arch/x86/kernel/kvm.c:918
Code: 4c 89 e8 48 c1 e8 03 42 0f b6 04 20 84 c0 44 8b 74 24 1c 75 34 41 0f b6 45 00 44 38 f0 75 10 66 90 0f 00 2d 5b 03 f3 03 fb f4 <e9> 24 ff ff ff fb e9 1e ff ff ff 44 89 e9 80 e1 07 38 c1 7c a3 4c
RSP: 0018:ffffc90004a8f140 EFLAGS: 00000246
RAX: 0000000000000003 RBX: 1ffff92000951e2c RCX: ffffffff8154fa7f
RDX: dffffc0000000000 RSI: 0000000000000003 RDI: ffff88810badd088
RBP: ffffc90004a8f1f0 R08: dffffc0000000000 R09: ffffed102175ba12
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff88810badd088 R14: 0000000000000003 R15: 1ffff92000951e30
FS:  00007f1d012b96c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32523000 CR3: 000000011c055000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 pv_wait arch/x86/include/asm/paravirt.h:597 [inline]
 pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
 __pv_queued_spin_lock_slowpath+0x6bc/0xc40 kernel/locking/qspinlock.c:508
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock include/linux/spinlock.h:187 [inline]
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
 _raw_spin_lock_bh+0x139/0x1b0 kernel/locking/spinlock.c:178
 sock_hash_delete_elem+0xb1/0x2f0 net/core/sock_map.c:937
 bpf_prog_2c29ac5cdc6b1842+0x3a/0x708
 bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
 __bpf_prog_run include/linux/filter.h:625 [inline]
 bpf_prog_run include/linux/filter.h:632 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1883 [inline]
 bpf_trace_run2+0xec/0x210 kernel/trace/bpf_trace.c:1920
 __bpf_trace_kfree+0x6f/0x90 include/trace/events/kmem.h:118
 trace_kfree include/trace/events/kmem.h:118 [inline]
 kfree+0x1f3/0x220 mm/slub.c:4569
 sk_psock_free_link include/linux/skmsg.h:420 [inline]
 sock_map_del_link net/core/sock_map.c:160 [inline]
 sock_map_unref+0x352/0x4d0 net/core/sock_map.c:182
 sock_hash_delete_elem+0x274/0x2f0 net/core/sock_map.c:941
 bpf_prog_2c29ac5cdc6b1842+0x3a/0x708
 bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
 __bpf_prog_run include/linux/filter.h:625 [inline]
 bpf_prog_run include/linux/filter.h:632 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1883 [inline]
 bpf_trace_run2+0xec/0x210 kernel/trace/bpf_trace.c:1920
 __bpf_trace_kfree+0x6f/0x90 include/trace/events/kmem.h:118
 trace_kfree include/trace/events/kmem.h:118 [inline]
 kfree+0x1f3/0x220 mm/slub.c:4569
 p9_client_create+0x5c6/0x1130 net/9p/client.c:1023
 v9fs_session_init+0x1fa/0x19b0 fs/9p/v9fs.c:409
 v9fs_mount+0x75/0x7f0 fs/9p/vfs_super.c:126
 legacy_get_tree+0xf1/0x190 fs/fs_context.c:611
 vfs_get_tree+0x88/0x290 fs/super.c:1517
 do_new_mount+0x2ba/0xb30 fs/namespace.c:3005
 path_mount+0x671/0x1070 fs/namespace.c:3335
 do_mount fs/namespace.c:3348 [inline]
 __do_sys_mount fs/namespace.c:3556 [inline]
 __se_sys_mount+0x2c4/0x3b0 fs/namespace.c:3533
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3533
 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+0x61/0xcb
RIP: 0033:0x7f1d02544ee9
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:00007f1d012b90c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f1d02673f80 RCX: 00007f1d02544ee9
RDX: 0000000020000040 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 00007f1d0259149e R08: 0000000020000300 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f1d02673f80 R15: 00007ffea7749f08
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/05/20 12:47 android13-5.15-lts 5d96939590c0 c0f1611a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 BUG: soft lockup in lo_ioctl
2024/04/28 17:41 android13-5.15-lts 5d96939590c0 07b455f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 BUG: soft lockup in lo_ioctl
* Struck through repros no longer work on HEAD.