syzbot


KMSAN: uninit-value in handle_bug

Status: upstream: reported C repro on 2025/12/06 14:30
Subsystems: bpf
[Documentation on labels]
Reported-by: syzbot+ba80855313e6fa65717a@syzkaller.appspotmail.com
First crash: 140d, last: 15d
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
16b78f53-f8ca-443b-9734-ef843726d668 repro KMSAN: uninit-value in handle_bug 2026/03/08 14:51 2026/03/08 14:51 2026/03/08 14:59 31e9c887f7dc24e04b3ca70d0d54fc34141844b0
Discussions (6)
Title Replies (including bot) Last reply
[syzbot] Monthly bpf report (Apr 2026) 0 (1) 2026/04/10 06:44
Re: KMSAN: uninit-value in eth_type_trans 1 (1) 2026/03/20 17:30
[syzbot] [bpf?] KMSAN: uninit-value in handle_bug 0 (2) 2026/03/17 06:45
[syzbot] Monthly bpf report (Mar 2026) 0 (1) 2026/03/09 23:06
[syzbot] Monthly bpf report (Feb 2026) 0 (1) 2026/02/06 14:30
[syzbot] Monthly bpf report (Jan 2026) 0 (1) 2026/01/07 07:29
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: stack-out-of-bounds Write in handle_bug mm 21 1 609d 609d 0/29 closed as invalid on 2024/09/13 10:29
Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/04/21 02:21 1h27m retest repro upstream report log

Sample crash report:
------------[ cut here ]------------
=====================================================
BUG: KMSAN: uninit-value in vsnprintf+0x15be/0x1b00 lib/vsprintf.c:2912
 vsnprintf+0x15be/0x1b00 lib/vsprintf.c:2912
 vprintk_store+0x350/0x1550 kernel/printk/printk.c:2307
 vprintk_emit+0x2c8/0xba0 kernel/printk/printk.c:2455
 vprintk_default+0x3f/0x50 kernel/printk/printk.c:2494
 vprintk+0x36/0x50 kernel/printk/printk_safe.c:82
 __warn_printf lib/bug.c:190 [inline]
 __report_bug+0xa10/0xe00 lib/bug.c:244
 report_bug_entry+0x17c/0x220 lib/bug.c:269
 handle_bug+0xe5/0x230 arch/x86/kernel/traps.c:430
 exc_invalid_op+0x1f/0x50 arch/x86/kernel/traps.c:489
 asm_exc_invalid_op+0x1f/0x30 arch/x86/include/asm/idtentry.h:616
 reg_bounds_sanity_check+0x571/0x14e0 kernel/bpf/verifier.c:2817
 reg_set_min_max+0x34b/0x450 kernel/bpf/verifier.c:17159
 check_cond_jmp_op+0x3bf5/0x5370 kernel/bpf/verifier.c:17609
 do_check_insn kernel/bpf/verifier.c:21168 [inline]
 do_check+0xc7e8/0x1add0 kernel/bpf/verifier.c:21308
 do_check_common+0x2705/0x4270 kernel/bpf/verifier.c:24650
 do_check_main kernel/bpf/verifier.c:24733 [inline]
 bpf_check+0x1f159/0x27e90 kernel/bpf/verifier.c:26056
 bpf_prog_load+0x2b41/0x3140 kernel/bpf/syscall.c:3089
 __sys_bpf+0x8e0/0xee0 kernel/bpf/syscall.c:6228
 __do_sys_bpf kernel/bpf/syscall.c:6341 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6339 [inline]
 __x64_sys_bpf+0xa4/0xf0 kernel/bpf/syscall.c:6339
 x64_sys_call+0x13d0/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 vsnprintf+0x15b7/0x1b00 lib/vsprintf.c:-1
 vprintk_store+0x350/0x1550 kernel/printk/printk.c:2307
 vprintk_emit+0x2c8/0xba0 kernel/printk/printk.c:2455
 vprintk_default+0x3f/0x50 kernel/printk/printk.c:2494
 vprintk+0x36/0x50 kernel/printk/printk_safe.c:82
 __warn_printf lib/bug.c:190 [inline]
 __report_bug+0xa10/0xe00 lib/bug.c:244
 report_bug_entry+0x17c/0x220 lib/bug.c:269
 handle_bug+0xe5/0x230 arch/x86/kernel/traps.c:430
 exc_invalid_op+0x1f/0x50 arch/x86/kernel/traps.c:489
 asm_exc_invalid_op+0x1f/0x30 arch/x86/include/asm/idtentry.h:616

Local variable pflags created at:
 try_charge_memcg+0x63/0x1c20 mm/memcontrol.c:2367
 obj_cgroup_charge_pages+0x69/0x330 mm/memcontrol.c:2857

CPU: 1 UID: 0 PID: 5997 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
=====================================================

Crashes (310):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/17 06:44 upstream 2d1373e4246d 0737c18f .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/04/03 23:54 upstream 631919fb12fe 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/04/02 02:10 upstream 9147566d8016 0cb124d5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/04/01 23:31 upstream 9147566d8016 0285fe54 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/04/01 23:30 upstream 9147566d8016 0285fe54 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/27 04:56 upstream 46b513250491 50cdcaa1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/26 16:55 upstream 0138af2472df fca8d360 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/26 10:31 upstream d2a43e7f89da c6143aac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/25 06:58 upstream bbeb83d3182a 35e4ff71 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/24 19:22 upstream e3c33bc767b5 74e70d19 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/24 14:05 upstream c369299895a5 74e70d19 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/24 01:28 upstream c369299895a5 baf8bf12 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/23 10:37 upstream c369299895a5 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/23 10:37 upstream c369299895a5 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/22 20:47 upstream 8d8bd2a5aa98 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/20 08:54 upstream 0e4f8f1a3d08 2f245add .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/20 03:09 upstream 8a30aeb0d1b4 bd6dcb30 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/17 12:22 upstream 2d1373e4246d c01bca74 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/17 09:13 upstream 2d1373e4246d c01bca74 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/17 00:31 upstream 2d1373e4246d 0737c18f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/11 04:18 upstream b4f0dd314b39 86914af9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/11 01:13 upstream b4f0dd314b39 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/09 15:19 upstream 1f318b96cc84 176bead5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/09 12:41 upstream 1f318b96cc84 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/08 23:01 upstream 014441d1e4b2 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/08 12:26 upstream c23719abc330 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/07 19:03 upstream 4ae12d8bd9a8 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/07 16:52 upstream 4ae12d8bd9a8 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/07 07:34 upstream 651690480a96 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/07 01:17 upstream 651690480a96 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/06 21:18 upstream 651690480a96 41d8037d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/06 17:49 upstream 5ee8dbf54602 41d8037d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/06 05:34 upstream 5ee8dbf54602 31e9c887 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/04 11:42 upstream cc25df3e2e22 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/04/07 01:48 upstream bfe62a454542 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/04/05 22:39 upstream 1791c390149f 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/04/05 16:08 upstream 3aae9383f42f 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/04/03 17:02 upstream d8a9a4b11a13 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/04/03 07:04 upstream 5619b098e2fb 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/04/03 06:59 upstream 5619b098e2fb 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/04/03 02:27 upstream 5619b098e2fb 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/04/03 01:13 upstream 5619b098e2fb 8b15d4ae .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/04/02 21:17 upstream 5619b098e2fb 8b15d4ae .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/04/02 14:19 upstream 9147566d8016 8b15d4ae .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/04/01 21:30 upstream 9147566d8016 0285fe54 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/03/10 02:20 upstream 1f318b96cc84 6972f302 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/03/09 10:28 upstream 1f318b96cc84 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/03/08 20:55 upstream 014441d1e4b2 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/03/07 10:15 upstream 651690480a96 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/03/07 01:59 upstream 651690480a96 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/03/06 23:40 upstream 651690480a96 41d8037d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2025/12/02 14:20 upstream 4a26e7032d7d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/04/04 08:19 upstream 631919fb12fe 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in handle_bug
2026/03/26 08:48 upstream d2a43e7f89da c6143aac .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in handle_bug
2026/02/27 20:26 upstream a75cb869a8cc 2cf092b8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in handle_bug
* Struck through repros no longer work on HEAD.