syzbot


BUG: soft lockup in x64_sys_call

Status: upstream: reported C repro on 2026/02/15 08:06
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+7f25199cde1fab5dc10d@syzkaller.appspotmail.com
First crash: 387d, last: 3d00h
Fix bisection: failed (error log, bisect log)
  
Bug presence (2)
Date Name Commit Repro Result
2026/02/15 lts (merge base) e50b81c50fcb C [report] BUG: soft lockup in sock_setsockopt
2026/02/15 upstream (ToT) ca4ee40bf13d C [report] BUG: soft lockup in x64_sys_call
Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-15 BUG: soft lockup in x64_sys_call origin:upstream 1 C 29 19d 556d 0/2 upstream: reported C repro on 2024/08/25 04:51
android-6-12 BUG: soft lockup in x64_sys_call 1 23 119d 253d 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 C 6 8d03h 7d18h 0/1 internal: reported C repro on 2026/02/24 16:10
linux-5.15 INFO: rcu detected stall in x64_sys_call 1 1 614d 614d 0/3 auto-obsoleted due to no activity on 2024/10/06 02:18
upstream INFO: rcu detected stall in x64_sys_call mm 1 C error 505 1d03h 540d 0/29 upstream: reported C repro on 2024/09/09 20:48
linux-6.1 INFO: rcu detected stall in x64_sys_call 1 1 305d 305d 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
2026/03/01 09:53 17m retest repro android14-6.1 report log
2026/01/08 19:38 10m retest repro android14-6.1 report log
2026/01/08 19:21 13m retest repro android14-6.1 report log
2026/01/08 19:21 13m retest repro android14-6.1 report log
Fix bisection attempts (2)
Created Duration User Patch Repo Result
2026/01/22 08:50 0m bisect fix android14-6.1 error job log
2025/06/03 21:27 1h30m bisect fix android14-6.1 OK (0) job log log

Sample crash report:
watchdog: BUG: soft lockup - CPU#0 stuck for 225s! [syz.2.1479:4808]
Modules linked in:
CPU: 0 PID: 4808 Comm: syz.2.1479 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:434 [inline]
RIP: 0010:__pv_queued_spin_lock_slowpath+0x591/0xc40 kernel/locking/qspinlock.c:511
Code: 0f 85 33 01 00 00 41 c6 45 00 00 41 0f b6 04 17 84 c0 0f 85 46 01 00 00 48 8b 44 24 10 c6 00 01 41 bd 00 80 ff ff eb 07 f3 90 <41> ff c5 74 5b 41 0f b6 04 16 84 c0 75 35 80 3b 00 75 eb 48 89 df
RSP: 0018:ffffc9000338f700 EFLAGS: 00000206
RAX: 0000000000000000 RBX: ffff88812a8c0098 RCX: ffffffff85007792
RDX: dffffc0000000000 RSI: 0000000000000003 RDI: ffff88812a8c0098
RBP: ffffc9000338f7f0 R08: ffff88812a8c0098 R09: 1ffff11025518013
R10: dffffc0000000000 R11: ffffed1025518014 R12: 1ffff1103edc0001
R13: 00000000ffffeaac R14: 1ffff11025518013 R15: 1ffff11025518013
FS:  00007fd42bdd66c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000000 CR3: 0000000131d56000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline]
 queued_spin_lock_slowpath+0x47/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock include/linux/spinlock.h:187 [inline]
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:127 [inline]
 _raw_spin_lock_bh+0xe4/0xf0 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:356 [inline]
 lock_sock_nested+0x90/0x2a0 net/core/sock.c:3515
 lock_sock include/net/sock.h:1818 [inline]
 tipc_sendstream+0x47/0x70 net/tipc/socket.c:1549
 sock_sendmsg_nosec net/socket.c:716 [inline]
 __sock_sendmsg net/socket.c:728 [inline]
 ____sys_sendmsg+0x5cc/0x990 net/socket.c:2509
 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2563
 __sys_sendmsg net/socket.c:2592 [inline]
 __do_sys_sendmsg net/socket.c:2601 [inline]
 __se_sys_sendmsg net/socket.c:2599 [inline]
 __x64_sys_sendmsg+0x205/0x2d0 net/socket.c:2599
 x64_sys_call+0x171/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd42af9bf79
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:00007fd42bdd6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fd42b215fa0 RCX: 00007fd42af9bf79
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000004
RBP: 00007fd42b0327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd42b216038 R14: 00007fd42b215fa0 R15: 00007ffc05a91468
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4809 Comm: syz.2.1479 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__kasan_check_read+0x0/0x20 mm/kasan/shadow.c:30
Code: 6a 86 eb 0a 48 c7 c7 d0 29 5f 86 48 89 de e8 bf cd 3e 03 45 31 ff eb d1 00 00 90 90 90 90 90 90 90 90 90 90 90 b8 f1 16 b4 ef <55> 48 89 e5 89 f6 48 8b 4d 08 31 d2 e8 cf e7 ff ff 5d c3 66 2e 0f
RSP: 0018:ffffc900032f6698 EFLAGS: 00000202
RAX: 0000000000000402 RBX: ffff88812a8c0098 RCX: ffffffff87b77103
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88812a8c0098
RBP: ffffc900032f6730 R08: ffff88812a8c0083 R09: 1ffff11025518010
R10: dffffc0000000000 R11: ffffed1025518011 R12: dffffc0000000000
R13: 1ffff9200065ecd4 R14: ffffffff84d8f7ce R15: ffff88812a8c0000
FS:  00007fd42bdb56c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd42bdb4ff8 CR3: 0000000131d56000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 spin_trylock_bh include/linux/spinlock.h:411 [inline]
 tipc_sk_rcv+0x43e/0x2c10 net/tipc/socket.c:2496
 tipc_node_xmit+0x26c/0xd90 net/tipc/node.c:1703
 tipc_node_xmit_skb net/tipc/node.c:1768 [inline]
 tipc_node_distr_xmit+0x2a3/0x3b0 net/tipc/node.c:1783
 tipc_sk_rcv+0x1a14/0x2c10 net/tipc/socket.c:2501
 tipc_node_xmit+0x26c/0xd90 net/tipc/node.c:1703
 tipc_sk_push_backlog+0x4dd/0x790 net/tipc/socket.c:1316
 tipc_sk_conn_proto_rcv net/tipc/socket.c:1370 [inline]
 tipc_sk_proto_rcv+0xa7c/0x15a0 net/tipc/socket.c:2158
 tipc_sk_filter_rcv+0x2b04/0x2cf0 net/tipc/socket.c:2352
 tipc_sk_enqueue net/tipc/socket.c:2445 [inline]
 tipc_sk_rcv+0x7ed/0x2c10 net/tipc/socket.c:2497
 tipc_node_xmit+0x26c/0xd90 net/tipc/node.c:1703
 tipc_node_xmit_skb net/tipc/node.c:1768 [inline]
 tipc_node_distr_xmit+0x2a3/0x3b0 net/tipc/node.c:1783
 tipc_sk_backlog_rcv+0x17d/0x210 net/tipc/socket.c:2412
 sk_backlog_rcv include/net/sock.h:1150 [inline]
 __release_sock+0x154/0x380 net/core/sock.c:2951
 release_sock net/core/sock.c:3527 [inline]
 sockopt_release_sock+0x95/0x1f0 net/core/sock.c:1067
 sk_setsockopt+0x1442/0x2730 net/core/sock.c:1545
 sock_setsockopt+0x5a/0x70 net/core/sock.c:1552
 __sys_setsockopt+0x269/0x4e0 net/socket.c:2274
 __do_sys_setsockopt net/socket.c:2289 [inline]
 __se_sys_setsockopt net/socket.c:2286 [inline]
 __x64_sys_setsockopt+0xbf/0xd0 net/socket.c:2286
 x64_sys_call+0x124/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:55
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd42af9bf79
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:00007fd42bdb5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007fd42b216090 RCX: 00007fd42af9bf79
RDX: 0000000000000021 RSI: 0000000000000001 RDI: 0000000000000003
RBP: 00007fd42b0327e0 R08: 0000000000000004 R09: 0000000000000000
R10: 0000200000000540 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd42b216128 R14: 00007fd42b216090 R15: 00007ffc05a91468
 </TASK>

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/15 07:56 android14-6.1 edbe3e111301 1e62d198 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1 BUG: soft lockup in x64_sys_call
2025/08/05 00:05 android14-6.1 3b4ff5af8d36 f5bcc8dc .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-6-1 BUG: soft lockup in x64_sys_call
2025/02/10 08:38 android14-6.1 1ac09f5c0571 ef44b750 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-6-1 BUG: soft lockup in x64_sys_call
2025/12/15 09:52 android14-6.1 6f1c2f8fd8c8 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf BUG: soft lockup in x64_sys_call
2025/11/30 15:35 android14-6.1 a92da54b7708 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf BUG: soft lockup in x64_sys_call
2025/09/30 06:13 android14-6.1 f6787ec80e17 86341da6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf BUG: soft lockup in x64_sys_call
2025/06/21 22:21 android14-6.1 f6c21bc9a693 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1-perf BUG: soft lockup in x64_sys_call
* Struck through repros no longer work on HEAD.