KASAN: vmalloc-out-of-bounds Read in kcov_remote_start

Status: upstream: reported on 2025/10/05 04:26
Subsystems: usb
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+8a173e13208949931dc7@syzkaller.appspotmail.com
Fix commit: 2eed77fdcb0c kcov: fix data corruption and race conditions on PREEMPT_RT
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-snapshot-upstream-root 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-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci-upstream-rust-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu-native-arm64-kvm ci-qemu2-arm32 ci-qemu2-riscv64 ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root]
First crash: 336d, last: 9d23h
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
4a93e1b2 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KASAN: vmalloc-out-of-bounds Read in kcov_remote_start 2026/05/23 06:13 2026/05/23 06:13 2026/05/23 07:07 c69befb3
▶ ▼ Discussions (10)
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
[syzbot] Monthly bluetooth report (Jul 2026) 0 (1) 2026/07/04 04:32
[PATCH] kcov: fix potential kcov_mode corruption under CONFIG_PREEMPT_RT 5 (5) 2026/05/21 08:38
[syzbot] Monthly usb report (May 2026) 0 (1) 2026/05/02 12:32
[syzbot] Monthly bluetooth report (May 2026) 0 (1) 2026/05/02 12:32
[syzbot] Monthly bluetooth report (Apr 2026) 0 (1) 2026/04/01 07:42
[syzbot] Monthly bluetooth report (Jan 2026) 0 (1) 2026/01/28 22:38
[syzbot] Monthly bluetooth report (Dec 2025) 0 (1) 2025/12/29 08:12
[syzbot] [usb?] KASAN: vmalloc-out-of-bounds Read in kcov_remote_start 0 (1) 2025/10/05 04:26

Sample crash report:
==================================================================
BUG: KASAN: vmalloc-out-of-bounds in __list_del_entry_valid_or_report+0xb5/0x190 lib/list_debug.c:65
Read of size 8 at addr ffffc90011005008 by task kworker/u9:0/60

CPU: 0 UID: 0 PID: 60 Comm: kworker/u9:0 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: hci1 hci_rx_work
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 __list_del_entry_valid_or_report+0xb5/0x190 lib/list_debug.c:65
 __list_del_entry_valid include/linux/list.h:140 [inline]
 __list_del_entry include/linux/list.h:254 [inline]
 list_del include/linux/list.h:268 [inline]
 kcov_remote_area_get kernel/kcov.c:143 [inline]
 kcov_remote_start+0x2aa/0x710 kernel/kcov.c:930
 kcov_remote_start_common include/linux/kcov.h:48 [inline]
 hci_rx_work+0x10f/0x1020 net/bluetooth/hci_core.c:4004
 process_one_work kernel/workqueue.c:3387 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551
 kthread+0x38b/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>

The buggy address belongs to a vmalloc virtual mapping
Memory state around the buggy address:
 ffffc90011004f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90011004f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90011005000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                      ^
 ffffc90011005080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90011005100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================

Crashes (3647):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/23 13:39 upstream 2709dd5ae32f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/23 09:54 upstream 2709dd5ae32f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/23 06:14 upstream 66fb95a52111 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/22 22:23 upstream 66fb95a52111 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/22 09:50 upstream 26260251022f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/21 16:04 upstream 818bebeb63dd 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/21 04:41 upstream 7f063b2f17ea 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/21 02:08 upstream 7f063b2f17ea 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/20 22:54 upstream a4ff2be345d0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/20 20:22 upstream a4ff2be345d0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/20 16:37 upstream a4ff2be345d0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/20 11:51 upstream a4ff2be345d0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/18 19:57 upstream 0f23d56f17fd 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/18 15:16 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/18 12:43 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/17 20:37 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/17 18:49 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/17 06:50 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/17 01:01 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/05/22 20:33 upstream 45255ea1ca09 e16cf9f3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/03/09 04:48 upstream 014441d1e4b2 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2025/10/05 02:43 upstream d104e3d17f7b 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2025/10/01 04:17 upstream 50c19e20ed2e 65a0eece .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/07/08 03:35 linux-next 5c73cd9f0819 88a4b44c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce KASAN: vmalloc-out-of-bounds Read in kcov_remote_start
2026/08/23 19:26 upstream 2709dd5ae32f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/23 16:21 upstream 2709dd5ae32f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/23 11:47 upstream 2709dd5ae32f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: corrupted list in kcov_remote_start
2026/08/23 09:01 upstream 2709dd5ae32f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/22 17:55 upstream 26260251022f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: corrupted list in kcov_remote_start
2026/08/22 12:33 upstream 26260251022f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/22 10:54 upstream 26260251022f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: corrupted list in kcov_remote_start
2026/08/22 06:50 upstream 26260251022f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: corrupted list in kcov_remote_start
2026/08/22 05:10 upstream 26260251022f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: corrupted list in kcov_remote_start
2026/08/22 01:58 upstream 818bebeb63dd 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/21 23:46 upstream 818bebeb63dd 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/21 18:13 upstream 818bebeb63dd 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/21 08:45 upstream 7f063b2f17ea 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/21 01:05 upstream a4ff2be345d0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/20 23:53 upstream a4ff2be345d0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/20 14:04 upstream a4ff2be345d0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/20 10:26 upstream 98f21c54f995 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: corrupted list in kcov_remote_start
2026/08/20 05:23 upstream 98f21c54f995 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/19 16:26 upstream bd5f485f3f02 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: corrupted list in kcov_remote_start
2026/08/19 14:35 upstream bd5f485f3f02 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: corrupted list in kcov_remote_start
2026/08/19 02:25 upstream 0f23d56f17fd 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel paging request in kcov_remote_start
2026/08/18 18:40 upstream 0f23d56f17fd 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/18 10:51 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: corrupted list in kcov_remote_start
2026/08/18 09:43 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/18 07:19 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: corrupted list in kcov_remote_start
2026/08/18 06:03 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: corrupted list in kcov_remote_start
2026/08/18 01:42 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel NULL pointer dereference 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 BUG: unable to handle kernel NULL pointer dereference in kcov_remote_start
2026/08/17 02:29 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: unable to handle kernel paging request in kcov_remote_start
2026/08/16 23:59 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: corrupted list in kcov_remote_start
2026/08/15 03:57 upstream 2f1baf1fc892 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root kernel BUG in kcov_remote_start
2026/07/08 14:04 linux-next 5c73cd9f0819 ab40da58 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root BUG: unable to handle kernel paging request in kcov_remote_start
* Struck through repros no longer work on HEAD.