BUG: soft lockup in ppp_ioctl

Status: auto-obsoleted due to no activity on 2024/11/22 22:02
Reported-by: syzbot+5d0b5422bf9c50a1035d@syzkaller.appspotmail.com
First crash: 857d, last: 730d
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in ppp_ioctl (3) 1 1 115d 115d 0/3 auto-obsoleted due to no activity on 2026/08/09 22:48
linux-5.15 INFO: rcu detected stall in ppp_ioctl 1 1 244d 244d 0/3 auto-obsoleted due to no activity on 2026/04/02 20:21
linux-6.1 INFO: rcu detected stall in ppp_ioctl 1 1 692d 692d 0/3 auto-obsoleted due to no activity on 2025/01/09 16:14
upstream INFO: rcu detected stall in ppp_ioctl mm 1 3 650d 665d 0/29 auto-obsoleted due to no activity on 2025/02/10 18:41
linux-6.1 INFO: rcu detected stall in ppp_ioctl (2) 1 1 312d 312d 0/3 auto-obsoleted due to no activity on 2026/01/24 16:32
linux-6.6 INFO: rcu detected stall in ppp_ioctl 1 1 65d 65d 0/2 upstream: reported on 2026/06/20 19:57

Sample crash report:
RBP: 00007f273022b93e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2730359f80 R15: 00007ffdbc972de8
 </TASK>
watchdog: BUG: soft lockup - CPU#1 stuck for 226s! [syz.2.471:2091]
Modules linked in:
CPU: 1 PID: 2091 Comm: syz.2.471 Not tainted 5.15.156-syzkaller-00821-g29d153aabd54 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
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 6b ef 12 04 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:ffffc90000b572c0 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 1ffff9200016ae5c RCX: 1ffffffff0d5ab14
RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff8881f7138ad4
RBP: ffffc90000b57370 R08: dffffc0000000000 R09: ffffed103ee2715b
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff8881f7138ad4 R14: 0000000000000001 R15: 1ffff9200016ae60
FS:  00007f272ee3b6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f46d70fdf98 CR3: 0000000134a3f000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
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+0x177/0x400 net/core/sock_map.c:943
 bpf_prog_586ab708469db861+0x41/0xb40
 bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
 __bpf_prog_run include/linux/filter.h:621 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1880 [inline]
 bpf_trace_run2+0x159/0x210 kernel/trace/bpf_trace.c:1917
 __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
 skb_free_head net/core/skbuff.c:656 [inline]
 skb_release_data+0x8a9/0xa80 net/core/skbuff.c:678
 skb_release_all net/core/skbuff.c:743 [inline]
 __kfree_skb net/core/skbuff.c:757 [inline]
 consume_skb+0xac/0x250 net/core/skbuff.c:930
 netlink_broadcast_filtered+0x10f4/0x1220 net/netlink/af_netlink.c:1540
 netlink_broadcast+0x3a/0x50 net/netlink/af_netlink.c:1562
 uevent_net_broadcast_tagged lib/kobject_uevent.c:372 [inline]
 kobject_uevent_net_broadcast+0x4f0/0x590 lib/kobject_uevent.c:412
 kobject_uevent_env+0x525/0x700 lib/kobject_uevent.c:593
 kobject_uevent+0x1f/0x30 lib/kobject_uevent.c:642
 rx_queue_add_kobject net/core/net-sysfs.c:1070 [inline]
 net_rx_queue_update_kobjects+0x213/0x490 net/core/net-sysfs.c:1110
 register_queue_kobjects net/core/net-sysfs.c:1767 [inline]
 netdev_register_kobject+0x231/0x320 net/core/net-sysfs.c:2018
 register_netdevice+0xde9/0x1390 net/core/dev.c:10364
 ppp_unit_register drivers/net/ppp/ppp_generic.c:1201 [inline]
 ppp_dev_configure+0x825/0xaf0 drivers/net/ppp/ppp_generic.c:1257
 ppp_create_interface drivers/net/ppp/ppp_generic.c:3332 [inline]
 ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1042 [inline]
 ppp_ioctl+0x601/0x19a0 drivers/net/ppp/ppp_generic.c:715
 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
 x64_sys_call+0x98/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f27301bde79
Code: 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 01 48
RSP: 002b:00007f272ee3b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2730359f80 RCX: 00007f27301bde79
RDX: 0000000020001400 RSI: 00000000c004743e RDI: 000000000000000b
RBP: 00007f273022b93e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2730359f80 R15: 00007ffdbc972de8
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 2107 Comm: syz.1.475 Not tainted 5.15.156-syzkaller-00821-g29d153aabd54 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
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 6b ef 12 04 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:ffffc90000ab7460 EFLAGS: 00000246
RAX: 0000000000000003 RBX: 1ffff92000156e90 RCX: ffffffff81552d3f
RDX: dffffc0000000000 RSI: 0000000000000003 RDI: ffff8881115a1c98
RBP: ffffc90000ab7510 R08: dffffc0000000000 R09: ffffed10222b4394
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff8881115a1c98 R14: 0000000000000003 R15: 1ffff92000156e94
FS:  00007f46d70fe6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000111078000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
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+0x177/0x400 net/core/sock_map.c:943
 bpf_prog_586ab708469db861+0x41/0xb40
 bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
 __bpf_prog_run include/linux/filter.h:621 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1880 [inline]
 bpf_trace_run2+0x159/0x210 kernel/trace/bpf_trace.c:1917
 __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+0x388/0x400 net/core/sock_map.c:947
 bpf_prog_cbcf82cd0a495324+0x45/0xae4
 bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
 __bpf_prog_run include/linux/filter.h:621 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 bpf_prog_run_pin_on_cpu include/linux/filter.h:652 [inline]
 bpf_flow_dissect+0x338/0x3e0 net/core/flow_dissector.c:887
 bpf_prog_test_run_flow_dissector+0x51a/0x860 net/bpf/test_run.c:901
 bpf_prog_test_run+0x3b0/0x630 kernel/bpf/syscall.c:3348
 __sys_bpf+0x525/0x760 kernel/bpf/syscall.c:4651
 __do_sys_bpf kernel/bpf/syscall.c:4737 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4735 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:4735
 x64_sys_call+0x87f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f46d84c2e79
Code: 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 01 48
RSP: 002b:00007f46d70fe038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f46d865f130 RCX: 00007f46d84c2e79
RDX: 0000000000000050 RSI: 0000000020000180 RDI: 000000000000000a
RBP: 00007f46d853093e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f46d865f130 R15: 00007ffd0b0aff58
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/08/24 22:00 android13-5.15-lts 29d153aabd54 d7d32352 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in ppp_ioctl
2024/07/04 14:15 android13-5.15-lts 9044d25b8ff5 3f2748a3 .config console log report info ci2-android-5-15-perf BUG: soft lockup in ppp_ioctl
2024/06/22 19:31 android13-5.15-lts 85445b5a2107 edc5149a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 BUG: soft lockup in ppp_ioctl
2024/05/23 06:20 android13-5.15-lts 5d96939590c0 4d098039 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in ppp_ioctl
2024/04/20 00:24 android13-5.15-lts ad06eaf051cd af24b050 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 BUG: soft lockup in ppp_ioctl
* Struck through repros no longer work on HEAD.