syzbot


KMSAN: uninit-value in handle_bug

Status: upstream: reported on 2025/12/06 14:30
Subsystems: bpf
[Documentation on labels]
Reported-by: syzbot+ba80855313e6fa65717a@syzkaller.appspotmail.com
First crash: 102d, last: 4d06h
✨ 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 (4)
Title Replies (including bot) Last reply
[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
[syzbot] [bpf?] KMSAN: uninit-value in handle_bug 0 (1) 2025/12/06 14:30
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 571d 571d 0/29 closed as invalid on 2024/09/13 10:29

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+0x2d8/0x450 kernel/bpf/verifier.c:17158
 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 rf created at:
 __schedule+0x3b/0x8640 kernel/sched/core.c:6772
 preempt_schedule_irq+0x50/0xa0 kernel/sched/core.c:7235

CPU: 1 UID: 0 PID: 12440 Comm: syz.0.1703 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
=====================================================

Crashes (248):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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
2026/03/05 01:35 upstream ecc64d2dc9ff a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/04 03:04 upstream 0031c06807cf 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/03 15:45 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/02 17:26 upstream 11439c4635ed b9dd6534 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/02 02:37 upstream e2bd1b136926 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/01 17:17 upstream eb71ab2bf722 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/03/01 13:31 upstream eb71ab2bf722 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/02/28 13:14 upstream 4d349ee5c778 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/02/28 10:57 upstream 4d349ee5c778 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/02/26 18:47 upstream f4d0ec0aa20d ffa54287 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/02/26 09:24 upstream d9d32e5bd5a4 e0f78d93 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/02/26 03:46 upstream d9d32e5bd5a4 e0f78d93 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/02/25 21:54 upstream d9d32e5bd5a4 df2e85d4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/02/25 14:54 upstream 7dff99b35460 df2e85d4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/02/25 03:16 upstream 7dff99b35460 787dfb7c .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
2026/03/10 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
2026/03/04 01:06 upstream 0031c06807cf 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/03/03 21:23 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/03/03 20:05 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/03/03 02:29 upstream af4e9ef3d784 28b83e23 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/03/02 14:45 upstream 11439c4635ed b9dd6534 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/03/01 20:44 upstream eb71ab2bf722 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/03/01 10:51 upstream eb71ab2bf722 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/02/28 17:48 upstream 4d349ee5c778 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/02/28 07:41 upstream 4d349ee5c778 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/02/27 23:28 upstream aed968f8a6cd 2cf092b8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/02/27 04:38 upstream a75cb869a8cc a2f13f71 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/02/26 17:09 upstream f4d0ec0aa20d ffa54287 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/02/26 01:25 upstream d9d32e5bd5a4 e0f78d93 .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
2026/02/27 20:26 upstream a75cb869a8cc 2cf092b8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in handle_bug
2026/02/24 23:17 upstream 7dff99b35460 787dfb7c .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.