WARNING in __ftrace_trace_stack

Status: upstream: reported C repro on 2026/07/31 04:11
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+250d50f4687a0b9010c2@syzkaller.appspotmail.com
First crash: 80d, last: 3d06h
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2026/08/15 linux-6.1.y (ToT) e4f7d8be268e C [report] WARNING in __ftrace_trace_stack
2026/08/15 upstream (ToT) 15ef2f78c49d C Didn't crash
▶ ▼ Fix bisection attempts (1)
Created Duration User Patch Repo Result
2026/08/24 04:54 2h10m fix candidate upstream OK (0) job log

Sample crash report:
L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.
------------[ cut here ]------------
memcpy: detected field-spanning write (size 128) of single field "&entry->caller" at kernel/trace/trace.c:3091 (size 64)
WARNING: CPU: 0 PID: 4430 at kernel/trace/trace.c:3091 __ftrace_trace_stack+0x3ce/0x530 kernel/trace/trace.c:3091
Modules linked in:
CPU: 0 PID: 4430 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__ftrace_trace_stack+0x3ce/0x530 kernel/trace/trace.c:3091
Code: fe ff ff e8 d4 4f fc ff c6 05 2a c1 86 0c 01 b9 40 00 00 00 48 c7 c7 60 7a 90 8a 4c 89 ee 48 c7 c2 00 92 90 8a e8 02 da c7 ff <0f> 0b e9 25 fe ff ff e8 a6 4f fc ff 48 8b 3c 24 4c 89 f6 e8 5a 88
RSP: 0018:ffffc900034578b8 EFLAGS: 00010246
RAX: 9064f39956f2ca00 RBX: ffff8880174c2028 RCX: ffff88807a123c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffff8880174c2018 R08: ffffc90003457547 R09: 1ffff9200068aea8
R10: dffffc0000000000 R11: fffff5200068aea9 R12: ffff8880b8e2b5e0
R13: 0000000000000080 R14: ffff8880174c2010 R15: 000000000000114e
FS:  000055557c512500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2df24008 CR3: 000000002c2e4000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 stacktrace_trigger+0xf0/0x140 kernel/trace/trace_events_trigger.c:1545
 event_triggers_post_call+0xfd/0x180 kernel/trace/trace_events_trigger.c:126
 do_trace_event_raw_event_kvm_hv_stimer_cleanup arch/x86/kvm/trace.h:1357 [inline]
 trace_event_raw_event_kvm_hv_stimer_cleanup+0x14b/0x220 arch/x86/kvm/trace.h:1357
 trace_kvm_hv_stimer_cleanup arch/x86/kvm/trace.h:1357 [inline]
 stimer_cleanup+0x3a7/0x430 arch/x86/kvm/hyperv.c:581
 kvm_hv_vcpu_uninit+0x4f/0xa0 arch/x86/kvm/hyperv.c:883
 kvm_arch_vcpu_destroy+0xba/0x270 arch/x86/kvm/x86.c:12143
 kvm_vcpu_destroy virt/kvm/kvm_main.c:495 [inline]
 kvm_destroy_vcpus+0xdd/0x250 virt/kvm/kvm_main.c:515
 kvm_arch_destroy_vm+0x31a/0x410 arch/x86/kvm/x86.c:12725
 kvm_destroy_vm virt/kvm/kvm_main.c:1336 [inline]
 kvm_put_kvm+0xdbb/0x1a10 virt/kvm/kvm_main.c:1370
 kvm_vm_release+0x42/0x50 virt/kvm/kvm_main.c:1393
 __fput+0x20a/0x8b0 fs/file_table.c:320
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8db999e0d9
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:00007fffae095078 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fffae095160 RCX: 00007f8db999e0d9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00000000000158d1 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2d320000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8db9c25fac R14: 00007f8db9c25fa8 R15: 00007f8db9c25fa0
 </TASK>

Crashes (114):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/06 07:20 linux-6.1.y fb28aa725e05 cd5b1963 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/10/16 01:42 linux-6.1.y 79807e970724 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/10/12 15:18 linux-6.1.y a500ba24937a 745a967f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/10/09 18:49 linux-6.1.y a500ba24937a 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/10/09 00:23 linux-6.1.y a500ba24937a b2734a59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/10/07 16:25 linux-6.1.y a500ba24937a 6520ecdb .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/10/07 11:11 linux-6.1.y a500ba24937a 6520ecdb .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/10/06 01:00 linux-6.1.y a500ba24937a f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/10/06 00:59 linux-6.1.y a500ba24937a f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/10/02 18:37 linux-6.1.y 1a8763b93150 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/10/02 03:01 linux-6.1.y 1a8763b93150 6d32eb1f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/30 19:31 linux-6.1.y 1a8763b93150 38f7f0d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/28 09:18 linux-6.1.y 1a8763b93150 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/24 15:17 linux-6.1.y 1a8763b93150 3c3cdf19 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/23 11:56 linux-6.1.y 1a8763b93150 abce1216 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/22 21:14 linux-6.1.y 1a8763b93150 5207b90e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/22 05:49 linux-6.1.y 1a8763b93150 e12281bd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/22 05:49 linux-6.1.y 1a8763b93150 e12281bd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/18 08:39 linux-6.1.y 1a8763b93150 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/17 00:00 linux-6.1.y 1a8763b93150 95928915 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/15 15:59 linux-6.1.y 1a8763b93150 2daa4bb5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/15 00:57 linux-6.1.y 1a8763b93150 81a27d1a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/10 12:04 linux-6.1.y cf82dcca9634 1fe56c0a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/09 18:44 linux-6.1.y cf82dcca9634 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/09 06:05 linux-6.1.y cf82dcca9634 8387c273 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/09 00:17 linux-6.1.y cf82dcca9634 243b72f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/08 16:34 linux-6.1.y cf82dcca9634 243b72f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/07 13:50 linux-6.1.y cf82dcca9634 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/03 05:22 linux-6.1.y cf82dcca9634 6a988719 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/02 16:06 linux-6.1.y cf82dcca9634 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/02 16:06 linux-6.1.y cf82dcca9634 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/02 14:17 linux-6.1.y d64a499eea6b 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/09/01 12:32 linux-6.1.y d64a499eea6b 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/31 20:03 linux-6.1.y d64a499eea6b 316d9396 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/31 18:19 linux-6.1.y d64a499eea6b 316d9396 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/31 02:43 linux-6.1.y d64a499eea6b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/29 07:39 linux-6.1.y d64a499eea6b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/24 16:39 linux-6.1.y 05208478041c b55bd4c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/23 05:09 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/22 13:01 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/21 05:40 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/21 01:32 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/19 22:47 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/18 04:09 linux-6.1.y e4f7d8be268e 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/17 15:16 linux-6.1.y e4f7d8be268e 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/17 09:54 linux-6.1.y e4f7d8be268e 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/15 04:09 linux-6.1.y e4f7d8be268e 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/14 16:10 linux-6.1.y e4f7d8be268e 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/08/14 16:10 linux-6.1.y e4f7d8be268e 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
2026/07/31 04:10 linux-6.1.y fb28aa725e05 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in __ftrace_trace_stack
* Struck through repros no longer work on HEAD.