BUG: soft lockup in x64_sys_call

Status: upstream: reported C repro on 2024/08/25 04:51
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+6e6b18b7bbb806b94ca7@syzkaller.appspotmail.com
First crash: 745d, last: 1d14h
Bug presence (3)
Date Name Commit Repro Result
2024/09/28 lts (merge base) 4878aadf2d15 C [report] BUG: soft lockup in sock_setsockopt
2024/09/28 upstream (ToT) ad46e8f95e93 C [report] BUG: soft lockup in x64_sys_call
2026/08/27 upstream (ToT) 73e3f0710014 C Failed due to an error; will retry later
Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-1 BUG: soft lockup in x64_sys_call origin:upstream 1 syz, C error 11 43d 205d 0/2 upstream: reported C repro on 2026/02/15 08:06
android-6-12 BUG: soft lockup in x64_sys_call 1 23 307d 442d 0/1 auto-obsoleted due to no activity on 2026/01/28 18:33
android-6-12 BUG: soft lockup in x64_sys_call (2) origin:upstream 1 syz, C 6 196d 196d 1/1 fixed on 2026/03/04 11:24
upstream INFO: rcu detected stall in x64_sys_call prio:low mm 1 syz, C error 647 2d02h 729d 0/29 upstream: reported C repro on 2024/09/09 20:48
linux-5.15 INFO: rcu detected stall in x64_sys_call 1 1 803d 803d 0/3 auto-obsoleted due to no activity on 2024/10/06 02:18
linux-5.15 INFO: rcu detected stall in x64_sys_call (2) 1 1 2d22h 2d22h 0/3 upstream: reported on 2026/09/06 08:22
linux-6.1 INFO: rcu detected stall in x64_sys_call 1 1 494d 494d 0/3 auto-obsoleted due to no activity on 2025/08/11 06:03
Last patch testing requests (4)
Created Duration User Patch Repo Result
2026/07/25 06:53 13m retest repro android13-5.15-lts log
2026/07/25 06:53 14m retest repro android13-5.15-lts log
2026/07/25 06:53 13m retest repro android13-5.15-lts log
2026/06/17 12:17 29m retest repro android13-5.15-lts log

Sample crash report:
watchdog: BUG: soft lockup - CPU#0 stuck for 246s! [syz.2.1079:3565]
Modules linked in:
CPU: 0 PID: 3565 Comm: syz.2.1079 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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+0x105/0x150 arch/x86/kernel/kvm.c:918
Code: 1b d6 03 f4 eb 87 fa 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 3f 0f b6 07 40 38 f0 75 10 66 90 0f 00 2d ed 1a d6 03 fb f4 <e9> 5e ff ff ff fb e9 58 ff ff ff e8 ab 28 7d 03 89 f9 80 e1 07 38
RSP: 0018:ffffc90000f1f6c0 EFLAGS: 00000246
RAX: 0000000000000003 RBX: ffff888118178588 RCX: ffffffff815004cc
RDX: 0000000000000001 RSI: 0000000000000003 RDI: ffff888118178588
RBP: ffffc90000f1f750 R08: ffff888118178588 R09: 1ffff1102302f0b1
R10: dffffc0000000000 R11: ffffed102302f0b2 R12: ffff88823ff52a40
R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff920001e3ed8
FS:  00007f9a4ba826c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000100 CR3: 000000011a3e0000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <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+0x605/0x9b0 kernel/locking/qspinlock.c:508
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline]
 queued_spin_lock_slowpath+0x47/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock include/linux/spinlock.h:188 [inline]
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
 _raw_spin_lock_bh+0xe4/0xf0 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:369 [inline]
 lock_sock_nested+0x95/0x2a0 net/core/sock.c:3278
 lock_sock include/net/sock.h:1743 [inline]
 tipc_sendstream+0x47/0x70 net/tipc/socket.c:1549
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x5be/0x8f0 net/socket.c:2436
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2490
 __sys_sendmsg net/socket.c:2519 [inline]
 __do_sys_sendmsg net/socket.c:2528 [inline]
 __se_sys_sendmsg net/socket.c:2526 [inline]
 __x64_sys_sendmsg+0x201/0x2d0 net/socket.c:2526
 x64_sys_call+0x4b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9a4bc21159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9a4ba82028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f9a4bea8fa0 RCX: 00007f9a4bc21159
RDX: 0000000000000941 RSI: 00002000000004c0 RDI: 0000000000000004
RBP: 00007f9a4bcb8024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9a4bea9038 R14: 00007f9a4bea8fa0 R15: 00007ffc09464c98
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3566 Comm: syz.2.1079 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__kasan_check_write+0x14/0x20 mm/kasan/shadow.c:37
Code: 31 d2 e8 af ed ff ff 5d c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 55 48 89 e5 89 f6 48 8b 4d 08 ba 01 00 00 00 e8 8c ed ff ff <5d> c3 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 57 41 56 53 48
RSP: 0018:ffffc90000f367d0 EFLAGS: 00000256
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: ffffffff84984850
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff888118178580
RBP: ffffc90000f367d0 R08: ffff888118178583 R09: 1ffff1102302f0b0
R10: dffffc0000000000 R11: ffffed102302f0b1 R12: ffffc90000f36c40
R13: ffff888118178580 R14: ffff888118178500 R15: 000000006599395c
FS:  00007f9a4ba616c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9a4ba60ff8 CR3: 000000011a3e0000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
 atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:167 [inline]
 __refcount_sub_and_test include/linux/refcount.h:272 [inline]
 __refcount_dec_and_test include/linux/refcount.h:315 [inline]
 refcount_dec_and_test include/linux/refcount.h:333 [inline]
 sock_put include/net/sock.h:1988 [inline]
 tipc_sk_rcv+0x1a50/0x2ca0 net/tipc/socket.c:2504
 tipc_node_xmit+0x36f/0xd80 net/tipc/node.c:1703
 tipc_node_xmit_skb net/tipc/node.c:1768 [inline]
 tipc_node_distr_xmit+0x277/0x390 net/tipc/node.c:1783
 tipc_sk_rcv+0x1a3f/0x2ca0 net/tipc/socket.c:2503
 tipc_node_xmit+0x36f/0xd80 net/tipc/node.c:1703
 tipc_sk_push_backlog+0x4d3/0x7b0 net/tipc/socket.c:1316
 tipc_sk_conn_proto_rcv net/tipc/socket.c:1370 [inline]
 tipc_sk_proto_rcv+0x9c3/0x1570 net/tipc/socket.c:2158
 tipc_sk_filter_rcv+0x2dde/0x2fd0 net/tipc/socket.c:2354
 tipc_sk_enqueue net/tipc/socket.c:2447 [inline]
 tipc_sk_rcv+0x787/0x2ca0 net/tipc/socket.c:2499
 tipc_node_xmit+0x36f/0xd80 net/tipc/node.c:1703
 tipc_node_xmit_skb net/tipc/node.c:1768 [inline]
 tipc_node_distr_xmit+0x277/0x390 net/tipc/node.c:1783
 tipc_sk_backlog_rcv+0x174/0x220 net/tipc/socket.c:2414
 sk_backlog_rcv include/net/sock.h:1090 [inline]
 __release_sock+0x17c/0x3f0 net/core/sock.c:2737
 release_sock net/core/sock.c:3290 [inline]
 sock_setsockopt+0x1a85/0x2470 net/core/sock.c:1381
 __sys_setsockopt+0x261/0x470 net/socket.c:2199
 __do_sys_setsockopt net/socket.c:2214 [inline]
 __se_sys_setsockopt net/socket.c:2211 [inline]
 __x64_sys_setsockopt+0xbf/0xd0 net/socket.c:2211
 x64_sys_call+0x982/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:55
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9a4bc21159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9a4ba61028 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f9a4bea9090 RCX: 00007f9a4bc21159
RDX: 0000000000000021 RSI: 0000000000000001 RDI: 0000000000000003
RBP: 00007f9a4bcb8024 R08: 0000000000000004 R09: 0000000000000000
R10: 00002000000001c0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9a4bea9128 R14: 00007f9a4bea9090 R15: 00007ffc09464c98
 </TASK>

Crashes (46):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/30 17:45 android13-5.15-lts 54850912d011 2f52988a .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2025/08/09 12:06 android13-5.15-lts f32b52534f1d 32a0e5ed .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2025/02/05 14:01 android13-5.15-lts d1a25a6a4b3b 5896748e .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/07 09:27 android13-5.15-lts 53be7c8abe11 9750182a .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2025/11/30 21:13 android13-5.15-lts 057fdbf6d3c7 d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/09/07 16:30 android13-5.15-lts e9b8a6529ffa 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/09/06 08:44 android13-5.15-lts e9b8a6529ffa 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/08/31 04:15 android13-5.15-lts 54850912d011 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/08/29 04:15 android13-5.15-lts 54850912d011 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/08/28 20:20 android13-5.15-lts 54850912d011 e2fa417d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/08/28 20:06 android13-5.15-lts 54850912d011 e2fa417d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/08/26 19:23 android13-5.15-lts 771777348d20 a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/08/16 03:46 android13-5.15-lts 54275df9611d 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/08/11 02:34 android13-5.15-lts 6148a1b6bae4 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 BUG: soft lockup in x64_sys_call
2026/08/06 09:51 android13-5.15-lts b885b84af7a2 cd5b1963 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/08/05 22:03 android13-5.15-lts b885b84af7a2 cd5b1963 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/06/25 22:36 android13-5.15-lts c85054db4618 7ff32d8b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/06/24 17:06 android13-5.15-lts c85054db4618 302586aa .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/05/26 06:23 android13-5.15-lts 05eea940894a c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2026/05/18 01:32 android13-5.15-lts 7f4b368e0410 de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 BUG: soft lockup in x64_sys_call
2026/05/14 20:41 android13-5.15-lts 7f4b368e0410 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 BUG: soft lockup in x64_sys_call
2026/02/12 13:52 android13-5.15-lts c3393955a6be 76a109e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/10/15 18:41 android13-5.15-lts 5e4635681cf1 7eb57b4a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/10/06 02:50 android13-5.15-lts 80dd36dca275 d7906eff .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/29 11:19 android13-5.15-lts 8e36931104ac ba29ff75 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/14 01:50 android13-5.15-lts e6fb3b0fa87f b58f933c .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/12 20:16 android13-5.15-lts e6fb3b0fa87f 60e1a995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/12 20:12 android13-5.15-lts e6fb3b0fa87f 60e1a995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/10 06:40 android13-5.15-lts c53388f01037 784df80e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/10 06:35 android13-5.15-lts c53388f01037 784df80e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/10 06:33 android13-5.15-lts c53388f01037 784df80e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/10 06:27 android13-5.15-lts c53388f01037 784df80e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/09 23:41 android13-5.15-lts c53388f01037 073f8be2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 BUG: soft lockup in x64_sys_call
2024/09/09 23:37 android13-5.15-lts c53388f01037 073f8be2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 BUG: soft lockup in x64_sys_call
2024/09/09 05:56 android13-5.15-lts 53be7c8abe11 9750182a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/08 08:05 android13-5.15-lts 53be7c8abe11 9750182a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/03 07:43 android13-5.15-lts 38761ec9fc9e 8045124c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/02 07:24 android13-5.15-lts 29d153aabd54 1eda0d14 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/02 02:36 android13-5.15-lts 29d153aabd54 1eda0d14 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/01 21:39 android13-5.15-lts 29d153aabd54 1eda0d14 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/09/01 18:17 android13-5.15-lts 29d153aabd54 1eda0d14 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 BUG: soft lockup in x64_sys_call
2024/09/01 18:12 android13-5.15-lts 29d153aabd54 1eda0d14 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 BUG: soft lockup in x64_sys_call
2024/09/01 08:40 android13-5.15-lts 29d153aabd54 1eda0d14 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/08/27 08:55 android13-5.15-lts 29d153aabd54 9aee4e0b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/08/25 04:40 android13-5.15-lts 29d153aabd54 d7d32352 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-5-15-perf BUG: soft lockup in x64_sys_call
2024/08/24 10:55 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 x64_sys_call
* Struck through repros no longer work on HEAD.