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dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id xBSUFwRyvWp+eQAAD6G6ig (envelope-from ); Wed, 30 Sep 2026 20:33:08 +0000 Message-ID: Date: Wed, 30 Sep 2026 22:31:57 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [syzbot] [openvswitch?] WARNING in set_ipv6_addr To: syzbot , aconole@redhat.com, davem@davemloft.net, dev@openvswitch.org, echaudro@redhat.com, edumazet@google.com, horms@kernel.org, i.maximets@ovn.org, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com References: <6abd40af.fac9d4e5.17396.0008.GAE@google.com> Content-Language: en-US From: Fernando Fernandez Mancera In-Reply-To: <6abd40af.fac9d4e5.17396.0008.GAE@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spamd-Result: default: False [-1.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; URI_HIDDEN_PATH(1.00)[https://syzkaller.appspot.com/x/.config?x=88147dd7e4cb6a0f]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; ARC_NA(0.00)[]; TAGGED_RCPT(0.00)[4cc63fcfb3845e149969]; MIME_TRACE(0.00)[0:+]; RCPT_COUNT_TWELVE(0.00)[13]; RCVD_VIA_SMTP_AUTH(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:mid,imap1.dmz-prg2.suse.org:helo,syzkaller.appspot.com:url,appspotmail.com:email]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; SUBJECT_HAS_QUESTION(0.00)[] X-Spam-Score: -1.80 X-Spam-Level: X-Spam-Flag: NO On 9/30/26 7:02 PM, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 47a144672573 Merge branch 'mptcp-misc-improvements-for-v7-4' > git tree: net-next > console+strace: https://syzkaller.appspot.com/x/log.txt?x=1342db25580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=88147dd7e4cb6a0f > dashboard link: https://syzkaller.appspot.com/bug?extid=4cc63fcfb3845e149969 > compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12c35e05580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11908035580000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/974586b80355/disk-47a14467.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/05ff7f1eb7cf/vmlinux-47a14467.xz > kernel image: https://storage.googleapis.com/syzbot-assets/d63ff990e2c6/bzImage-47a14467.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+4cc63fcfb3845e149969@syzkaller.appspotmail.com > > ovs-dp0: entered promiscuous mode > ------------[ cut here ]------------ > !skb_transport_header_was_set(skb) > WARNING: ./include/linux/skbuff.h:3075 at skb_transport_header include/linux/skbuff.h:3075 [inline], CPU#1: syz-executor463/5635 > WARNING: ./include/linux/skbuff.h:3075 at skb_transport_offset include/linux/skbuff.h:3250 [inline], CPU#1: syz-executor463/5635 > WARNING: ./include/linux/skbuff.h:3075 at update_ipv6_checksum net/openvswitch/actions.c:361 [inline], CPU#1: syz-executor463/5635 > WARNING: ./include/linux/skbuff.h:3075 at set_ipv6_addr+0x462/0x660 net/openvswitch/actions.c:399, CPU#1: syz-executor463/5635 > Modules linked in: > CPU: 1 UID: 0 PID: 5635 Comm: syz-executor463 Not tainted syzkaller #0 PREEMPT(full) > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 > RIP: 0010:skb_transport_header include/linux/skbuff.h:3075 [inline] > RIP: 0010:skb_transport_offset include/linux/skbuff.h:3250 [inline] > RIP: 0010:update_ipv6_checksum net/openvswitch/actions.c:361 [inline] > RIP: 0010:set_ipv6_addr+0x462/0x660 net/openvswitch/actions.c:399 > Code: f6 e8 12 d3 05 00 ba 10 00 00 00 4c 89 ef 48 89 ee 48 83 c4 20 5b 41 5c 41 5d 41 5e 41 5f 5d e9 14 89 7a f6 e8 ff 80 0a f6 90 <0f> 0b 90 48 8b 44 24 10 42 0f b6 04 30 84 c0 0f 85 c8 01 00 00 41 > RSP: 0018:ffffc90003b3ee68 EFLAGS: 00010293 > RAX: ffffffff8bbd5b01 RBX: 000000000000ffff RCX: ffff8880780bbe80 > RDX: 0000000000000000 RSI: 000000000000ffff RDI: 000000000000ffff > RBP: 000000000000004c R08: 0000000000000001 R09: 0000000000000011 > R10: 000000000000001f R11: 0000000000000000 R12: ffff888071cdbd36 > R13: ffff88802d028396 R14: dffffc0000000000 R15: ffff888071cdbc80 > FS: 0000555579c36400(0000) GS:ffff888124dc5000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007ffd90696af0 CR3: 000000007065a000 CR4: 00000000003526f0 > Call Trace: > > set_ipv6 net/openvswitch/actions.c:531 [inline] > execute_masked_set_action net/openvswitch/actions.c:1073 [inline] > do_execute_actions+0x557e/0x8600 net/openvswitch/actions.c:1366 > ovs_execute_actions+0xde/0x520 net/openvswitch/actions.c:1592 > ovs_packet_cmd_execute+0xb4f/0xf10 net/openvswitch/datapath.c:705 > genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114 > genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] > genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209 > netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2572 > genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 > netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline] > netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1361 > netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1916 > sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800 > __sock_sendmsg net/socket.c:818 [inline] > ____sys_sendmsg+0x54e/0x850 net/socket.c:2715 > ___sys_sendmsg+0x2a5/0x360 net/socket.c:2769 > __sys_sendmsg net/socket.c:2801 [inline] > __do_sys_sendmsg net/socket.c:2806 [inline] > __se_sys_sendmsg net/socket.c:2804 [inline] > __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2804 > do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] > do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7fe073a4fd39 > Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 d8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007ffece969af8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > RAX: ffffffffffffffda RBX: 00007ffece969c28 RCX: 00007fe073a4fd39 > RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000003 > RBP: 0000000000000001 R08: 00007ffece969c28 R09: 00007ffece969c28 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffece969c18 > R13: 0000000000000002 R14: 00007fe073ae0ca0 R15: 0000000000000002 > > > Hi, I have a fix for this trace. I have verified it with the reproducer but I want to do a more testing before sending it, so will send it tomorrow. In addition, I am not so sure about how likely can this be hit in a production environment.. as fragmentation isn't common and conntrack auto-reassembly should kick in.. pretty edge-case in my opinion. Thanks, Fernando.