KCSAN: data-race in _prb_read_valid / data_alloc

Status: moderation: reported on 2025/04/25 22:51
Subsystems: ext4
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+808447001465ab29f335@syzkaller.appspotmail.com
First crash: 458d, last: 1d12h
✨ AI Jobs (4)
ID Workflow Result Correct Bug Created Started Finished Revision Error
e74241a4 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ✅ NetworkTrigger: ✅ PeripheralTrigger: ✅ RemoteTrigger: ✅ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ✅ KCSAN: data-race in _prb_read_valid / data_alloc 2026/05/17 00:13 2026/05/17 00:13 2026/05/17 00:45 de5aae85

			
		
273760ae repro KCSAN: data-race in _prb_read_valid / data_alloc 2026/03/07 23:14 2026/03/07 23:14 2026/03/07 23:16 31e9c887

			
		
fb3eaf3e assessment-kcsan Benign: ✅ Confident: ✅ KCSAN: data-race in _prb_read_valid / data_alloc 2026/02/24 21:11 2026/02/24 21:11 2026/02/24 21:15 305c0ec5

			
		
0dfcd390 assessment-kcsan 💥 KCSAN: data-race in _prb_read_valid / data_alloc 2026/01/10 03:13 2026/01/10 03:13 2026/01/10 03:13 75199160
Error 429, Message: You exceeded your current quota, please check your plan and billing details. For more information on this error, head to: https://ai.google.dev/gemini-api/docs/rate-limits. To moni...
truncated to first 200 bytes; open job for full error

Sample crash report:
==================================================================
BUG: KCSAN: data-race in _prb_read_valid / data_alloc

write to 0xffffffff86c76e10 of 8 bytes by task 28 on cpu 0:
 data_alloc+0x2fc/0x380 kernel/printk/printk_ringbuffer.c:1129
 prb_reserve+0x8e3/0xaf0 kernel/printk/printk_ringbuffer.c:1727
 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354
 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2455
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2504
 kauditd_printk_skb kernel/audit.c:588 [inline]
 kauditd_hold_skb+0x1b1/0x1c0 kernel/audit.c:623
 kauditd_send_queue+0x275/0x2d0 kernel/audit.c:808
 kauditd_thread+0x439/0x660 kernel/audit.c:932
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffffff86c76e10 of 16 bytes by task 19880 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:496 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1934 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1982 [inline]
 _prb_read_valid+0x183/0x930 kernel/printk/printk_ringbuffer.c:2173
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2245
 printk_get_next_message+0xea/0x550 kernel/printk/printk.c:3052
 console_emit_next_record kernel/printk/printk.c:3137 [inline]
 console_flush_one_record kernel/printk/printk.c:3269 [inline]
 console_flush_all+0x2bc/0x6b0 kernel/printk/printk.c:3343
 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
 console_unlock+0xa1/0x280 kernel/printk/printk.c:3413
 vprintk_emit+0x3e4/0x600 kernel/printk/printk.c:2479
 dev_vprintk_emit+0x242/0x2a0 drivers/base/core.c:4996
 dev_printk_emit+0x84/0xb0 drivers/base/core.c:5007
 __dev_printk+0xf3/0x110 drivers/base/core.c:5019
 _dev_err+0xa6/0xd0 drivers/base/core.c:5062
 raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:600 [inline]
 raw_ioctl+0x1b2d/0x1df0 drivers/usb/gadget/legacy/raw_gadget.c:1307
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
 x64_sys_call+0x1563/0x3020 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 19880 Comm: syz.1.3316 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
==================================================================

Crashes (555):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/27 07:45 upstream 4235cb24ec1e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/26 14:11 upstream 3dab139d4795 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/26 05:00 upstream 0ce37745d4bf 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/25 19:46 upstream 0ce37745d4bf 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/24 22:14 upstream 48a5a7ab8d6a dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/24 03:44 upstream d326f83e819c 544adce9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/23 14:13 upstream 4539944e5151 71a13572 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/23 02:57 upstream 4539944e5151 881ce5c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/22 04:40 upstream 248951ddc14d b561ce9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/21 20:46 upstream 248951ddc14d 7c5de9c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/21 16:56 upstream b95f03f04d47 7c5de9c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/20 15:07 upstream 1590cf032971 de6a700d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/20 02:19 upstream 82a47586c0b9 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/19 10:46 upstream c6859eed755d 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/18 07:03 upstream 94515f3a7d42 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/17 11:52 upstream fce2dfa773ce 7f27c57a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/16 18:30 upstream 37e2f878a7a6 71b49442 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/16 02:16 upstream 58717b2a1365 27a8bd60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/13 01:33 upstream f4fb100039e9 d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/12 15:40 upstream 44696aa3a489 d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/11 22:49 upstream dd3210c47e8d d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/11 10:07 upstream 61c03dfde854 d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/10 02:18 upstream a635d6748234 4167ee25 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/09 12:56 upstream 0e35b9b6ec0f a0c310a3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/08 12:33 upstream 0e35b9b6ec0f 88a4b44c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/07 07:42 upstream 0e35b9b6ec0f 8e71ce95 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/05 17:00 upstream f105f3631d51 fcece630 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/05 03:30 upstream 7404ce516372 fcece630 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/02 19:02 upstream 4a50a141f05a 2b70b115 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/07/01 06:45 upstream 665159e24674 00a5cf1c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/30 16:00 upstream dc59e4fea9d8 00e8b0fd .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/29 13:59 upstream dc59e4fea9d8 6a0c72dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/28 21:23 upstream 8b69c0475871 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/27 14:05 upstream 5a66900afbd6 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/26 16:27 upstream 4edcdefd4083 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/26 10:50 upstream 4edcdefd4083 7ff32d8b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/24 05:54 upstream 558ef39aeb9a 042555ff .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/22 19:11 upstream 1dc18801be29 5a630be6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/22 13:24 upstream ef0c9f75a195 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/20 12:48 upstream 1a3746ccbb0a 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/19 17:18 upstream 9ecfb2f7287a 570c59ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/19 03:33 upstream 83f1454877cc a776b0d0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/18 14:22 upstream e771677c937d a776b0d0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/17 08:48 upstream 6b5a2b7d9bc1 62cc6db3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/16 18:34 upstream b1cbabe84ca1 a3998659 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/06/14 18:35 upstream 8cd9520d35a6 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/16 12:25 upstream d458a240344c a15a64a6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/03/07 02:29 upstream 651690480a96 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/02/24 11:47 upstream 7dff99b35460 96b1aa46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/01/09 09:10 upstream 623fb9912f6a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2025/04/25 22:50 upstream 02ddfb981de8 c6b4fb39 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
* Struck through repros no longer work on HEAD.