From: syzbot <syzbot+619b9ef527f510a57cfc@syzkaller.appspotmail.com>
To: kartikey406@gmail.com, linux-kernel@vger.kernel.org,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [bpf?] KMSAN: uninit-value in bpf_prog_test_run_skb
Date: Sat, 03 Jan 2026 21:21:02 -0800 [thread overview]
Message-ID: <6959f8be.050a0220.a1b6.0384.GAE@google.com> (raw)
In-Reply-To: <20260104034826.7723-1-kartikey406@gmail.com>
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in bpf_prog_test_run_skb
=====================================================
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+0x3b1/0x16b0 net/core/skbuff.c:2291
__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+0x20a/0x16b0 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: 0 UID: 0 PID: 6518 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(none)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
=====================================================
Tested on:
commit: aacb0a6d Merge tag 'pmdomain-v6.19-rc3' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1682169a580000
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
patch: https://syzkaller.appspot.com/x/patch.diff?x=1109da9a580000
next parent reply other threads:[~2026-01-04 5:21 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260104034826.7723-1-kartikey406@gmail.com>
2026-01-04 5:21 ` syzbot [this message]
[not found] <20260330023746.1917493-1-sun.jian.kdev@gmail.com>
2026-03-30 3:45 ` [syzbot] [bpf?] KMSAN: uninit-value in bpf_prog_test_run_skb syzbot
2026-01-14 13:56 [PATCH] net: skbuff: fix uninitialized memory use in pskb_expand_head() Soham Metha
2026-01-14 15:06 ` [syzbot] [bpf?] KMSAN: uninit-value in bpf_prog_test_run_skb syzbot
[not found] <20260114123333.13206-1-sohammetha01@gmail.com>
2026-01-14 13:44 ` syzbot
[not found] <20260114120911.9472-1-sohammetha01@gmail.com>
2026-01-14 12:17 ` syzbot
[not found] <20260104035833.8404-1-kartikey406@gmail.com>
2026-01-04 6:12 ` syzbot
[not found] <20260104020145.4942-1-kartikey406@gmail.com>
2026-01-04 2:26 ` syzbot
[not found] <20260102021954.297351-1-kartikey406@gmail.com>
2026-01-02 2:45 ` syzbot
-- strict thread matches above, loose matches on Subject: below --
2025-12-31 6:02 syzbot
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