From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f206.google.com (mail-oi1-f206.google.com [209.85.167.206]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5ADCD282EB for ; Wed, 31 Dec 2025 06:02:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.206 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767160947; cv=none; b=UxHC/SuOwwF53yOQmw28Aab+gaUYO4FnKSjyH1t3vWbncX41tkhj5PkOONmFGuZ9bn7GM94sal4EaCOSdS1HyLXnNO69NVtiZubIPhdWZNmZM3YonId9A4Yfqx9PrS6KcKllGlFa7X+8ZV+upAFrsBlpLgX9CXKTiHSUyNH4FmY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767160947; c=relaxed/simple; bh=41g0UrPy2dQNGw7AYwGDLuTbBGlGH04qfUcw+LF3pHk=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; 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List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:4ec8:b0:65e:e522:bf0a with SMTP id 006d021491bc7-65ee522bf77mr3188269eaf.36.1767160944242; Tue, 30 Dec 2025 22:02:24 -0800 (PST) Date: Tue, 30 Dec 2025 22:02:24 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6954bc70.050a0220.a1b6.0310.GAE@google.com> Subject: [syzbot] [bpf?] KMSAN: uninit-value in bpf_prog_test_run_skb From: syzbot To: andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, eddyz87@gmail.com, haoluo@google.com, john.fastabend@gmail.com, jolsa@kernel.org, kpsingh@kernel.org, linux-kernel@vger.kernel.org, martin.lau@linux.dev, sdf@fomichev.me, song@kernel.org, syzkaller-bugs@googlegroups.com, yonghong.song@linux.dev Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 3f0e9c8cefa9 Merge tag 'block-6.19-20251226' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14d784fc580000 kernel config: https://syzkaller.appspot.com/x/.config?x=b3903bdf68407a14 dashboard link: https://syzkaller.appspot.com/bug?extid=619b9ef527f510a57cfc compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=151f1b92580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=144f5022580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/7f2d5650d243/disk-3f0e9c8c.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/069034860f2d/vmlinux-3f0e9c8c.xz kernel image: https://storage.googleapis.com/syzbot-assets/90d1c240dc1b/bzImage-3f0e9c8c.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+619b9ef527f510a57cfc@syzkaller.appspotmail.com ===================================================== BUG: KMSAN: uninit-value in bpf_prog_test_run_skb+0x3091/0x3200 net/bpf/test_run.c:-1 bpf_prog_test_run_skb+0x3091/0x3200 net/bpf/test_run.c:-1 bpf_prog_test_run+0x5bb/0x9f0 kernel/bpf/syscall.c:4703 __sys_bpf+0x873/0xeb0 kernel/bpf/syscall.c:6182 __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+0xd3/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was stored to memory at: pskb_expand_head+0x310/0x15d0 net/core/skbuff.c:2290 __skb_cow include/linux/skbuff.h:3853 [inline] skb_cow_head include/linux/skbuff.h:3887 [inline] bpf_skb_net_grow net/core/filter.c:3511 [inline] ____bpf_skb_adjust_room net/core/filter.c:3754 [inline] bpf_skb_adjust_room+0x103c/0x3310 net/core/filter.c:3699 ___bpf_prog_run+0x1297/0xeba0 kernel/bpf/core.c:2037 __bpf_prog_run512+0xc5/0x100 kernel/bpf/core.c:2333 bpf_dispatcher_nop_func include/linux/bpf.h:1378 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] bpf_test_run+0x496/0xe00 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x2377/0x3200 net/bpf/test_run.c:1158 bpf_prog_test_run+0x5bb/0x9f0 kernel/bpf/syscall.c:4703 __sys_bpf+0x873/0xeb0 kernel/bpf/syscall.c:6182 __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+0xd3/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was stored to memory at: skb_data_move+0x424/0x570 include/linux/skbuff.h:-1 skb_postpush_data_move include/linux/skbuff.h:4639 [inline] bpf_skb_generic_push net/core/filter.c:3267 [inline] bpf_skb_net_hdr_push net/core/filter.c:3305 [inline] bpf_skb_net_grow net/core/filter.c:3542 [inline] ____bpf_skb_adjust_room net/core/filter.c:3754 [inline] bpf_skb_adjust_room+0x116c/0x3310 net/core/filter.c:3699 ___bpf_prog_run+0x1297/0xeba0 kernel/bpf/core.c:2037 __bpf_prog_run512+0xc5/0x100 kernel/bpf/core.c:2333 bpf_dispatcher_nop_func include/linux/bpf.h:1378 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] bpf_test_run+0x496/0xe00 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x2377/0x3200 net/bpf/test_run.c:1158 bpf_prog_test_run+0x5bb/0x9f0 kernel/bpf/syscall.c:4703 __sys_bpf+0x873/0xeb0 kernel/bpf/syscall.c:6182 __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+0xd3/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:4960 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_node_noprof+0x9e7/0x17a0 mm/slub.c:5315 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:586 pskb_expand_head+0x1fc/0x15d0 net/core/skbuff.c:2282 __skb_cow include/linux/skbuff.h:3853 [inline] skb_cow_head include/linux/skbuff.h:3887 [inline] bpf_skb_net_grow net/core/filter.c:3511 [inline] ____bpf_skb_adjust_room net/core/filter.c:3754 [inline] bpf_skb_adjust_room+0x103c/0x3310 net/core/filter.c:3699 ___bpf_prog_run+0x1297/0xeba0 kernel/bpf/core.c:2037 __bpf_prog_run512+0xc5/0x100 kernel/bpf/core.c:2333 bpf_dispatcher_nop_func include/linux/bpf.h:1378 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] bpf_test_run+0x496/0xe00 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x2377/0x3200 net/bpf/test_run.c:1158 bpf_prog_test_run+0x5bb/0x9f0 kernel/bpf/syscall.c:4703 __sys_bpf+0x873/0xeb0 kernel/bpf/syscall.c:6182 __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+0xd3/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 1 UID: 0 PID: 6072 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(none) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 ===================================================== --- This report is generated by a bot. 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