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: 58d, last: 2d14h
Discussions (2)
Title Replies (including bot) Last reply
[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 23 1 526d 526d 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:2911
 vsnprintf+0x15be/0x1b00 lib/vsprintf.c:2911
 vprintk_store+0x350/0x1550 kernel/printk/printk.c:2255
 vprintk_emit+0x2c8/0xba0 kernel/printk/printk.c:2402
 vprintk_default+0x3f/0x50 kernel/printk/printk.c:2441
 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+0xe1/0x230 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:2742
 reg_set_min_max+0x2d8/0x450 kernel/bpf/verifier.c:16575
 check_cond_jmp_op+0x3bed/0x5360 kernel/bpf/verifier.c:17010
 do_check_insn kernel/bpf/verifier.c:20446 [inline]
 do_check+0xa487/0x19a20 kernel/bpf/verifier.c:20586
 do_check_common+0x2706/0x4250 kernel/bpf/verifier.c:23870
 do_check_main kernel/bpf/verifier.c:23953 [inline]
 bpf_check+0x1e5a4/0x27320 kernel/bpf/verifier.c:25260
 bpf_prog_load+0x2b41/0x3140 kernel/bpf/syscall.c:3088
 __sys_bpf+0x7df/0xeb0 kernel/bpf/syscall.c:6164
 __do_sys_bpf kernel/bpf/syscall.c:6274 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6272 [inline]
 __x64_sys_bpf+0xa4/0xf0 kernel/bpf/syscall.c:6272
 x64_sys_call+0x31c3/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0xf80 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:2255
 vprintk_emit+0x2c8/0xba0 kernel/printk/printk.c:2402
 vprintk_default+0x3f/0x50 kernel/printk/printk.c:2441
 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+0xe1/0x230 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 reuse.i created at:
 mas_wr_node_store lib/maple_tree.c:3495 [inline]
 mas_wr_store_entry+0x1191/0x93d0 lib/maple_tree.c:3764
 mas_store_prealloc+0x1830/0x1df0 lib/maple_tree.c:5169

CPU: 0 UID: 0 PID: 6785 Comm: syz.4.274 Tainted: G             L      syzkaller #0 PREEMPT(voluntary) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
=====================================================

Crashes (42):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/27 04:22 upstream fcb70a56f4d8 efb3e894 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/01/17 22:54 upstream d3eeb99bbc99 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/01/17 21:36 upstream d3eeb99bbc99 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/01/14 19:39 upstream c537e12daeec d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/01/13 09:57 upstream b71e635feefc d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/01/10 00:37 upstream 372800cb95a3 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/01/05 21:14 upstream 3609fa95fb0f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/01/05 18:17 upstream 3609fa95fb0f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/01/04 17:55 upstream aacb0a6d604a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/01/03 14:06 upstream 805f9a061372 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/01/03 01:07 upstream 9b0436804460 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/01/01 21:36 upstream b69053dd3ffb d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/31 21:42 upstream c8ebd433459b d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/30 14:57 upstream 8640b74557fc d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/29 07:34 upstream c875a6c32467 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/27 18:20 upstream c53f467229a7 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/27 09:08 upstream 3f0e9c8cefa9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/24 23:18 upstream ccd1cdca5cd4 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/14 03:55 upstream 4a298a43f5e3 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/12 02:15 upstream d358e5254674 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/11 15:09 upstream d358e5254674 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/10 09:06 upstream c9b47175e913 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/09 17:57 upstream cb015814f8b6 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/08 07:04 upstream c2f2b01b74be d6526ea3 .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
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
2025/12/04 01:11 upstream 3f9f0252130e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/03 18:18 upstream 3f9f0252130e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/03 18:02 upstream 3f9f0252130e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/03 04:34 upstream 44fc84337b6e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2025/12/02 15:18 upstream 4a26e7032d7d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in handle_bug
2026/01/08 17:28 upstream f0b9d8eb98df d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2026/01/08 15:01 upstream f0b9d8eb98df d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2025/12/25 01:56 upstream ccd1cdca5cd4 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2025/12/19 08:58 upstream 516471569089 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2025/12/17 23:11 upstream ea1013c15392 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2025/12/11 18:51 upstream d358e5254674 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2025/12/07 20:12 upstream 37bb2e7217b0 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: uninit-value in handle_bug
2025/12/04 02:56 upstream 3f9f0252130e d6526ea3 .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
2025/12/16 08:18 upstream 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in handle_bug
2025/12/08 08:01 upstream ba65a4e7120a d6526ea3 .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.