syzbot


KCSAN: data-race in _prb_read_valid / data_alloc

Status: moderation: reported on 2025/04/25 22:51
Subsystems: net ext4
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+808447001465ab29f335@syzkaller.appspotmail.com
First crash: 396d, last: 18h42m
✨ AI Jobs (4)
ID Workflow Result Correct Bug Created Started Finished Revision Error
e74241a4-b2eb-4225-b79a-aced118b9d61 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 de5aae85e5f28e2fa1c7deefcc24fe286abe5140
273760ae-6956-4bef-bbd6-6bf146ef8176 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 31e9c887f7dc24e04b3ca70d0d54fc34141844b0
fb3eaf3e-96bd-422f-b4ca-56bccf7ad6e0 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 305c0ec5cd886e2d13738e28e1b2df9b0ec20fc9
0dfcd390-1613-412c-855c-b9d02fa2fe22 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 7519916073b761ced56a7b15fdeeb4674e8dc125 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 monitor your current usage, head to: https://ai.dev/rate-limit. * Quota exceeded for metric: generativelanguage.googleapis.com/generate_requests_per_model_per_day, limit: 0, Status: RESOURCE_EXHAUSTED, Details: [map[@type:type.googleapis.com/google.rpc.Help links:[map[description:Learn more about Gemini API quotas url:https://ai.google.dev/gemini-api/docs/rate-limits]]] map[@type:type.googleapis.com/google.rpc.QuotaFailure violations:[map[quotaId:GenerateRequestsPerDayPerProjectPerModel quotaMetric:generativelanguage.googleapis.com/generate_requests_per_model_per_day]]] map[@type:type.googleapis.com/google.rpc.DebugInfo detail:[ORIGINAL ERROR] generic::resource_exhausted: 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 monitor your current usage, head to: https://ai.dev/rate-limit. * Quota exceeded for metric: generativelanguage.googleapis.com/generate_requests_per_model_per_day, limit: 0 [google.rpc.error_details_ext] { 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 monitor your current usage, head to: https://ai.dev/rate-limit. \n* Quota exceeded for metric: generativelanguage.googleapis.com/generate_requests_per_model_per_day, limit: 0" details { type_url: "type.googleapis.com/language_labs.genai.debug.GeminiApiDebugInfo" value: "RM\nK\nEgenerativelanguage.googleapis.com/generate_requests_per_model_per_day\030\000\"\000" } details { [type.googleapis.com/google.rpc.Help] { links { description: "Learn more about Gemini API quotas" url: "https://ai.google.dev/gemini-api/docs/rate-limits" } } } details { [type.googleapis.com/google.rpc.QuotaFailure] { violations { quota_metric: "generativelanguage.googleapis.com/generate_requests_per_model_per_day" quota_id: "GenerateRequestsPerDayPerProjectPerModel" } } } }]]

Sample crash report:
loop9: lost filesystem error report for type 5 error -117
EXT4-fs error (device loop9): ext4_quota_off:7318: inode #3: comm syz-executor: mark_inode_dirty error
==================================================================
BUG: KCSAN: data-race in _prb_read_valid / data_alloc

write to 0xffffffff86c76580 of 8 bytes by task 6642 on cpu 1:
 data_alloc+0x310/0x390 kernel/printk/printk_ringbuffer.c:1129
 prb_reserve+0x8d6/0xad0 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
 usb_gadget_register_driver_owner+0x17e/0x1a0 drivers/usb/gadget/udc/core.c:1730
 raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:596 [inline]
 raw_ioctl+0xc6c/0x1e10 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+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86c76580 of 16 bytes by task 3714 on cpu 0:
 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+0x1b6/0x950 kernel/printk/printk_ringbuffer.c:2173
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2245
 __console_flush_and_unlock kernel/printk/printk.c:3392 [inline]
 console_unlock+0x146/0x280 kernel/printk/printk.c:3413
 vprintk_emit+0x3e4/0x600 kernel/printk/printk.c:2479
 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
 __ext4_error_inode+0x2af/0x3c0 fs/ext4/super.c:861
 __ext4_mark_inode_dirty+0xbd/0x3d0 fs/ext4/inode.c:6561
 ext4_quota_off+0x248/0x290 fs/ext4/super.c:7318
 ext4_quotas_off fs/ext4/super.c:1195 [inline]
 ext4_put_super+0xc5/0x7b0 fs/ext4/super.c:1306
 generic_shutdown_super+0xee/0x220 fs/super.c:646
 kill_block_super+0x2a/0x70 fs/super.c:1725
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7492
 deactivate_locked_super+0x75/0x1c0 fs/super.c:476
 deactivate_super+0x97/0xa0 fs/super.c:509
 cleanup_mnt+0x2bb/0x330 fs/namespace.c:1312
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1319
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0x211/0x820 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x232/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3714 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================
loop9: lost file I/O error report for ino 3 type 5 pos 0x0 len 0x0 error -117

Crashes (478):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/26 23:45 upstream d60ec36cab33 2b01f00e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/25 18:20 upstream e7ae89a0c97c c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/23 20:43 upstream eed108edc117 c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/23 05:01 upstream 79bd2dded182 c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/22 17:49 upstream 45255ea1ca09 5f091fcc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/22 03:04 upstream 6779b50faa56 70ae9b03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/21 20:30 upstream 758c807bb943 e195359d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/21 15:40 upstream 8bc67e4db64a e195359d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/21 09:51 upstream 8bc67e4db64a 41b8c833 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/20 04:43 upstream 27fa82620cba 0909d65f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/19 13:53 upstream ab5fce87a778 223544dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/18 14:17 upstream 5200f5f493f7 55156e84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/17 23:21 upstream e5d505e3664b de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/17 14:41 upstream 6916d5703ddf de5aae85 .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
2026/05/16 01:29 upstream d458a240344c 81fb92f3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/14 03:49 upstream e1914add2799 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/12 20:55 upstream c21b90f77687 a0949470 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/12 13:49 upstream 50897c955902 07aeade5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/11 20:29 upstream 5d6919055dec d168f260 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/11 08:55 upstream 5d6919055dec 845acb1c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/11 00:19 upstream 5d6919055dec 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/10 13:10 upstream 1bfaee9d3351 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/09 20:21 upstream e92b2872d0b1 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/07 15:42 upstream 8ab992f815d6 cbf9e0fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/07 09:38 upstream 5862221fdded f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/06 17:51 upstream 74fe02ce122a 1dddfd3d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/05 17:28 upstream a293ec25d59d 06e69a27 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/04 22:49 upstream c7e4e4d5f7dc a898ba9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/04 20:51 upstream 6d35786de281 a898ba9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/04 08:33 upstream 6d35786de281 85f1bcf2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/03 05:48 upstream 66edb901bf87 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/02 10:57 upstream f1a5e78a55eb a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/01 19:49 upstream 6fe0be6dc7fa 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/05/01 06:12 upstream 26fd6bff2c05 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/30 14:56 upstream e75a43c7cec4 a7464baf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/30 11:44 upstream e75a43c7cec4 a7464baf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/29 20:49 upstream 57b8e2d666a3 005438fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/29 15:23 upstream 57b8e2d666a3 7ca9e4d8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/28 22:10 upstream dca922e019dd 95008c03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/28 10:35 upstream 3b3bea6d4b9c ce741359 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/27 01:30 upstream 20b64cf8705a 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/25 18:44 upstream 897d54018cc9 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/22 11:44 upstream 6596a02b2078 4595e353 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/21 22:36 upstream 4ee64205ffaa 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/21 07:01 upstream b4e07588e743 3f2e655b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/20 21:48 upstream a5d1079c28a5 e65da4ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/20 14:56 upstream c1f49dea2b8f e65da4ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/20 03:18 upstream c1f49dea2b8f 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in _prb_read_valid / data_alloc
2026/04/18 20:41 upstream eb5249b12507 303e2802 .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.