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Thu, 10 Mar 2022 13:57:54 -0800 (PST) X-Google-Smtp-Source: ABdhPJx3J07rWqPVHpRbRgAfNIsa2YEkK9fYYXo5WB/bsFY89DjXNQc74Jsib2unZpspwGd+tFoaoQ== X-Received: by 2002:a05:6402:34cb:b0:415:b974:ec5c with SMTP id w11-20020a05640234cb00b00415b974ec5cmr6424283edc.329.1646949473831; Thu, 10 Mar 2022 13:57:53 -0800 (PST) Received: from alrua-x1.borgediget.toke.dk ([2a0c:4d80:42:443::2]) by smtp.gmail.com with ESMTPSA id g16-20020a170906521000b006d58773e992sm2222909ejm.188.2022.03.10.13.57.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Mar 2022 13:57:53 -0800 (PST) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 74D661A8990; Thu, 10 Mar 2022 22:57:52 +0100 (CET) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Martin KaFai Lau Cc: andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, davem@davemloft.net, hawk@kernel.org, john.fastabend@gmail.com, kpsingh@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, songliubraving@fb.com, syzkaller-bugs@googlegroups.com, yhs@fb.com, syzbot Subject: Re: [syzbot] BUG: missing reserved tailroom In-Reply-To: <20220310210626.25o2mll3jmp62swy@kafai-mbp.dhcp.thefacebook.com> References: <00000000000019c51e05d9e18158@google.com> <20220310210626.25o2mll3jmp62swy@kafai-mbp.dhcp.thefacebook.com> X-Clacks-Overhead: GNU Terry Pratchett Date: Thu, 10 Mar 2022 22:57:52 +0100 Message-ID: <87ee39xyfz.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Martin KaFai Lau writes: > On Thu, Mar 10, 2022 at 10:37:20AM -0800, syzbot wrote: >> Hello, >>=20 >> syzbot found the following issue on: >>=20 >> HEAD commit: de55c9a1967c Merge branch 'Add support for transmitting = pa.. >> git tree: bpf-next >> console output: https://syzkaller.appspot.com/x/log.txt?x=3D14ce88ad7000= 00 >> kernel config: https://syzkaller.appspot.com/x/.config?x=3D2fa13781bcea= 50fc >> dashboard link: https://syzkaller.appspot.com/bug?extid=3D0e91362d99386d= c5de99 >> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binut= ils for Debian) 2.35.2 >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=3D11f3634570= 0000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=3D14c8ca657000= 00 >>=20 >> The issue was bisected to: >>=20 >> commit b530e9e1063ed2b817eae7eec6ed2daa8be11608 >> Author: Toke H=C3=B8iland-J=C3=B8rgensen >> Date: Wed Mar 9 10:53:42 2022 +0000 >>=20 >> bpf: Add "live packet" mode for XDP in BPF_PROG_RUN >>=20 >> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=3D17696e557= 00000 >> final oops: https://syzkaller.appspot.com/x/report.txt?x=3D14e96e557= 00000 >> console output: https://syzkaller.appspot.com/x/log.txt?x=3D10e96e557000= 00 >>=20 >> IMPORTANT: if you fix the issue, please add the following tag to the com= mit: >> Reported-by: syzbot+0e91362d99386dc5de99@syzkaller.appspotmail.com >> Fixes: b530e9e1063e ("bpf: Add "live packet" mode for XDP in BPF_PROG_RU= N") >>=20 >> ------------[ cut here ]------------ >> XDP_WARN: xdp_update_frame_from_buff(line:274): Driver BUG: missing rese= rved tailroom >> WARNING: CPU: 0 PID: 3590 at net/core/xdp.c:599 xdp_warn+0x28/0x30 net/c= ore/xdp.c:599 > Toke, please take a look. Right, I see the problem; will send a fix! -Toke