WARNING in kcov_remote_start (6)

Status: upstream: reported on 2024/11/04 21:25
Subsystems: kernel
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+3f51ad7ac3ae57a6fdcc@syzkaller.appspotmail.com
Fix commit: kcov: fix data corruption and race conditions on PREEMPT_RT
Patched on: [ci-upstream-linux-next-kasan-gce-root ci-upstream-rust-kasan-gce], missing on: [ci-qemu-gce-upstream-auto ci-qemu-native-arm64-kvm ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb]
First crash: 655d, last: 5m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
7c1201c5 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in kcov_remote_start (6) 2026/05/24 13:26 2026/05/24 13:26 2026/05/24 14:13 c69befb3
Discussions (14)
Title Replies (including bot) Last reply
[PATCH v6] kcov: fix data corruption and race conditions on PREEMPT_RT by moving saved remote state to task_struct 5 (5) 2026/07/16 09:12
Re: [PATCH v5] kcov: fix data corruption and race conditions on PREEMPT_RT by moving saved remote state to task_struct 2 (2) 2026/07/10 10:43
Re: Policy regarding linux-next only changes 2 (2) 2026/07/02 14:11
[PATCH] kcov: fix potential kcov_mode corruption under CONFIG_PREEMPT_RT 5 (5) 2026/05/21 08:38
[syzbot] [wireless?] WARNING in kcov_remote_start (6) 0 (2) 2026/05/07 11:10
[PATCH (draft)] kcov: fix potential kcov_mode corruption under CONFIG_PREEMPT_RT 2 (2) 2026/05/04 15:39
[syzbot] Monthly wireless report (May 2026) 0 (1) 2026/05/02 12:32
[syzbot] Monthly wireless report (Apr 2026) 0 (1) 2026/04/01 07:42
[syzbot] Monthly wireless report (Mar 2026) 0 (1) 2026/03/01 06:22
[syzbot] Monthly wireless report (Jan 2026) 0 (1) 2026/01/28 22:39
[syzbot] Monthly usb report (Dec 2025) 0 (1) 2025/12/29 08:12
[syzbot] Monthly wireless report (Dec 2025) 0 (1) 2025/12/29 08:12
[syzbot] Monthly wireless report (Nov 2025) 0 (1) 2025/11/27 07:44
[syzbot] Monthly wireless report (Oct 2025) 0 (1) 2025/10/27 08:42
Similar bugs (10)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in kcov_remote_start (2) -1 1 173d 173d 0/3 auto-obsoleted due to no activity on 2026/06/06 04:25
linux-5.15 WARNING in kcov_remote_start -1 4 585d 685d 0/3 auto-obsoleted due to no activity on 2025/04/19 19:40
linux-5.15 WARNING in kcov_remote_start (3) -1 1 38d 38d 0/3 upstream: reported on 2026/07/10 20:40
linux-6.6 WARNING in kcov_remote_start -1 1 88d 88d 0/2 upstream: reported on 2026/05/22 01:58
upstream WARNING in kcov_remote_start (4) usb -1 107983 769d 799d 26/29 fixed on 2024/07/10 08:24
upstream WARNING in kcov_remote_start (2) usb -1 syz, C 1153 2540d 2540d 0/29 closed as invalid on 2019/09/04 14:27
upstream WARNING in kcov_remote_start (5) wireless -1 4243 665d 765d 28/29 fixed on 2024/10/22 14:56
upstream WARNING in kcov_remote_start (3) usb -1 265513 803d 873d 25/29 fixed on 2024/06/05 13:52
upstream WARNING in kcov_remote_start usb -1 syz, C 655 2540d 2541d 0/29 closed as invalid on 2019/09/03 16:37
linux-6.1 WARNING in kcov_remote_start -1 14 14d 415d 0/3 upstream: reported on 2025/06/28 15:34

Sample crash report:
------------[ cut here ]------------
in_task() && kcov_mode_enabled(mode)
WARNING: kernel/kcov.c:894 at kcov_remote_start+0x5bb/0x6f0 kernel/kcov.c:894, CPU#0: kworker/u8:11/1427
Modules linked in:
CPU: 0 UID: 0 PID: 1427 Comm: kworker/u8:11 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:kcov_remote_start+0x5bb/0x6f0 kernel/kcov.c:894
Code: 03 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d e9 ec 84 fd 02 90 0f 0b 90 eb d1 90 0f 0b 90 0f b7 83 c0 04 00 00 e9 b7 fa ff ff 90 <0f> 0b 90 eb 04 90 0f 0b 90 e8 67 38 80 09 89 c0 48 c7 c7 c0 12 9f
RSP: 0018:ffffc9000678f9f8 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffff8880297e0000 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff8bca7160 RDI: ffffffff8bca7120
RBP: ffff888033a8a8c0 R08: ffffffff8b485c40 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8e1c3100 R12: dffffc0000000000
R13: ffff8880625c5ef8 R14: 0000000000000000 R15: ffff888062721180
FS:  0000000000000000(0000) GS:ffff888125c38000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f97173c5ff8 CR3: 00000000384b2000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 kcov_remote_start_common include/linux/kcov.h:48 [inline]
 ieee80211_iface_work+0x20c/0x1010 net/mac80211/iface.c:1818
 cfg80211_wiphy_work+0x29e/0x420 net/wireless/core.c:538
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (42669):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/18 13:09 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/18 11:58 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/18 10:34 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/18 10:20 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/18 09:20 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/18 08:05 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/18 07:17 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/18 06:15 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/18 04:43 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/18 03:28 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/18 02:02 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/18 01:24 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/18 00:21 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 22:14 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 21:09 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 19:56 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 18:45 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 17:41 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 16:20 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 15:19 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 13:52 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 12:47 upstream 8d3ae59288f1 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 10:31 upstream 8d3ae59288f1 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 06:21 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 05:03 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 03:59 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 02:59 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 01:46 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 01:43 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/17 00:33 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 23:24 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 22:12 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 22:08 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 21:08 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 19:52 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 18:46 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 16:15 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 15:29 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 13:53 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 12:48 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 11:29 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 09:21 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 08:15 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/08/16 07:10 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/05/24 12:17 upstream 4cbfe4502e3d c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/04/03 00:19 upstream 5619b098e2fb 8b15d4ae .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in kcov_remote_start
2026/03/10 13:57 upstream 1f318b96cc84 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/03/06 16:42 upstream 5ee8dbf54602 41d8037d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in kcov_remote_start
2026/03/01 08:48 upstream 42eb01783091 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in kcov_remote_start
2026/01/29 08:52 upstream 8dfce8991b95 b78a7341 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in kcov_remote_start
2025/08/30 22:55 upstream 11e7861d680c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in kcov_remote_start
2024/11/03 07:56 upstream 3e5e6c9900c3 f00eed24 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in kcov_remote_start
2026/02/24 08:18 upstream 7dff99b35460 41d2fa6a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 WARNING in kcov_remote_start
2026/01/18 12:58 upstream d12453c7e281 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in kcov_remote_start
2025/09/02 13:14 upstream b320789d6883 96a211bc .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in kcov_remote_start
2025/12/28 12:00 upstream d26143bb38e2 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in kcov_remote_start
2026/07/20 12:14 bpf 94515f3a7d42 de6a700d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-bpf-kasan-gce WARNING in kcov_remote_start
2025/10/12 09:27 net f3426ac54c42 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in kcov_remote_start
2026/05/07 17:37 bpf-next 2ca6723a5f7b e358bca5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-bpf-next-kasan-gce WARNING in kcov_remote_start
2025/08/18 08:17 net-next bab3ce404553 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in kcov_remote_start
2026/07/08 14:17 linux-next 5c73cd9f0819 ab40da58 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in kcov_remote_start
2026/07/08 11:07 linux-next 5c73cd9f0819 ab40da58 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in kcov_remote_start
2024/10/31 21:14 linux-next f9f24ca362a4 96eb609f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in kcov_remote_start
2025/04/28 17:47 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci c72692105976 c6b4fb39 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in kcov_remote_start
* Struck through repros no longer work on HEAD.