kernel BUG in pskb_expand_head (6)

Status: upstream: reported C repro on 2026/10/18 02:07
Subsystems: tipc
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+0017742620a9d06f06ef@syzkaller.appspotmail.com
First crash: 9d06h, last: 2d23h
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
96c9bb79 repro-c Reproduced: ✅ ❓ kernel BUG in pskb_expand_head (6) 2026/10/16 14:30 2026/10/16 14:30 2026/10/16 15:03 432c0077
b66281a1 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ✅ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ❌ ❓ kernel BUG in pskb_expand_head (6) 2026/10/12 00:44 2026/10/12 00:44 2026/10/12 01:45 4f92358f
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[PATCH net] tipc: fix refcount panic in tipc_rcv() when receiving shared skb 1 (1) 2026/10/19 05:05
[PATCH] tipc: unshare skb in tipc_l2_rcv_msg() before decrypting 2 (2) 2026/10/19 05:01
[syzbot] [tipc?] kernel BUG in pskb_expand_head (6) 0 (1) 2026/10/18 02:07
▶ ▼ Similar bugs (12)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 kernel BUG in pskb_expand_head (2) -1 14 26d 197d 0/3 upstream: reported on 2026/04/05 20:08
linux-5.15 kernel BUG in pskb_expand_head (2) origin:lts-only -1 syz, C done 7 425d 458d 2/3 upstream: reported C repro on 2025/07/18 14:25
android-5-15 kernel BUG in pskb_expand_head -1 syz, C 17 412d 453d 0/2 auto-obsoleted due to no activity on 2025/11/11 01:09
android-6-1 kernel BUG in pskb_expand_head -1 1 1230d 1230d 0/2 auto-obsoleted due to no activity on 2023/09/05 19:11
upstream kernel BUG in pskb_expand_head (4) intel-wired-lan -1 1 599d 599d 28/29 fixed on 2025/06/10 16:19
upstream kernel BUG in pskb_expand_head (5) net -1 syz, C error error 32 221d 275d 0/29 auto-obsoleted due to no activity on 2026/05/08 15:21
upstream kernel BUG in pskb_expand_head (3) net -1 1 848d 848d 0/29 closed as invalid on 2024/09/04 18:07
upstream kernel BUG in pskb_expand_head (2) bpf net -1 10 1243d 1258d 0/29 auto-obsoleted due to no activity on 2023/08/23 09:08
linux-5.15 kernel BUG in pskb_expand_head -1 1 1282d 1282d 0/3 auto-obsoleted due to no activity on 2023/08/14 13:19
upstream kernel BUG in llc_sap_action_send_xid_c net -1 syz, C error 61 1805d 2019d 20/29 fixed on 2021/11/10 00:50
upstream kernel BUG in pskb_expand_head net -1 syz, C done 1600 1348d 1799d 22/29 fixed on 2023/02/25 08:02
linux-6.1 kernel BUG in pskb_expand_head -1 1 1238d 1238d 0/3 auto-obsoleted due to no activity on 2023/09/07 17:22
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/10/16 22:00 24m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2f2f7eeef8b0a1a9b9ca998231419873ccae8d4e report job log log
▶ ▼ Cause bisection attempts (1)
Created Duration User Patch Repo Result
2026/10/18 02:04 0m bisect git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git error

Sample crash report:
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:2308!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 5940 Comm: syz-executor216 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
RIP: 0010:pskb_expand_head+0x135a/0x13a0 net/core/skbuff.c:2308
Code: e9 10 f3 ff ff e8 76 06 1b f8 4c 89 e7 48 c7 c6 80 0c 23 8d e8 97 19 7b f7 90 0f 0b e8 5f 06 1b f8 90 0f 0b e8 57 06 1b f8 90 <0f> 0b 89 d1 80 e1 07 80 c1 03 38 c1 0f 8c d8 fa ff ff 48 8b 3c 24
RSP: 0018:ffffc90000007520 EFLAGS: 00010246
RAX: ffffffff89ad0a29 RBX: dffffc0000000000 RCX: ffff88802a490000
RDX: 8000000000000100 RSI: 0000000000000100 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000100 R09: 1ffff1100e875c3a
R10: dffffc0000000000 R11: ffffed100e875c3b R12: 0000000000000820
R13: 0000000000000000 R14: 0000000000000002 R15: ffff8880743ae0f0
FS:  000055557b02f400(0000) GS:ffff888123abf000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff61507fa8 CR3: 000000007506a000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __pskb_pull_tail+0x111/0x1870 net/core/skbuff.c:2890
 skb_cow_data+0x2ed/0xc50 net/core/skbuff.c:5398
 tipc_aead_decrypt net/tipc/crypto.c:892 [inline]
 tipc_crypto_rcv+0x346/0x23d0 net/tipc/crypto.c:1843
 tipc_rcv+0x4b7/0x1040 net/tipc/node.c:2119
 tipc_l2_rcv_msg+0x2d9/0x470 net/tipc/bearer.c:669
 deliver_ptype_list_skb net/core/dev.c:2533 [inline]
 __netif_receive_skb_core+0x2988/0x30c0 net/core/dev.c:6254
 __netif_receive_skb_one_core net/core/dev.c:6295 [inline]
 __netif_receive_skb net/core/dev.c:6410 [inline]
 process_backlog+0x727/0x18b0 net/core/dev.c:6761
 __napi_poll+0xaa/0x330 net/core/dev.c:7830
 napi_poll net/core/dev.c:7893 [inline]
 net_rx_action+0x61d/0xf50 net/core/dev.c:8050
 handle_softirqs+0x226/0x860 kernel/softirq.c:645
 do_softirq+0x77/0xd0 kernel/softirq.c:546
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:923 [inline]
 __dev_queue_xmit+0x1efb/0x3920 net/core/dev.c:4993
 dev_queue_xmit include/linux/netdevice.h:3464 [inline]
 tipc_l2_send_msg+0x331/0x400 net/tipc/bearer.c:517
 tipc_bearer_xmit_skb+0x2b3/0x400 net/tipc/bearer.c:576
 tipc_enable_bearer net/tipc/bearer.c:366 [inline]
 __tipc_nl_bearer_enable+0x10ec/0x1480 net/tipc/bearer.c:1048
 tipc_nl_bearer_enable+0x22/0x40 net/tipc/bearer.c:1057
 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:2579
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1338 [inline]
 netlink_unicast+0x8ef/0xa80 net/netlink/af_netlink.c:1364
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1923
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
 __sock_sendmsg net/socket.c:815 [inline]
 __sys_sendto+0x408/0x5a0 net/socket.c:2281
 __do_sys_sendto net/socket.c:2288 [inline]
 __se_sys_sendto net/socket.c:2284 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2284
 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: 0033:0x7f091b73dcf7
Code: 48 89 fa 4c 89 df e8 98 1d 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fff615088d0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000055557b02f400 RCX: 00007f091b73dcf7
RDX: 0000000000000028 RSI: 00007fff61509950 RDI: 0000000000000005
RBP: 0000000000000005 R08: 00007fff61508924 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000005
R13: 00007f091b77b018 R14: 00007f091b7a2cc0 R15: 0000000000000002
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:pskb_expand_head+0x135a/0x13a0 net/core/skbuff.c:2308
Code: e9 10 f3 ff ff e8 76 06 1b f8 4c 89 e7 48 c7 c6 80 0c 23 8d e8 97 19 7b f7 90 0f 0b e8 5f 06 1b f8 90 0f 0b e8 57 06 1b f8 90 <0f> 0b 89 d1 80 e1 07 80 c1 03 38 c1 0f 8c d8 fa ff ff 48 8b 3c 24
RSP: 0018:ffffc90000007520 EFLAGS: 00010246
RAX: ffffffff89ad0a29 RBX: dffffc0000000000 RCX: ffff88802a490000
RDX: 8000000000000100 RSI: 0000000000000100 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000100 R09: 1ffff1100e875c3a
R10: dffffc0000000000 R11: ffffed100e875c3b R12: 0000000000000820
R13: 0000000000000000 R14: 0000000000000002 R15: ffff8880743ae0f0
FS:  000055557b02f400(0000) GS:ffff888123abf000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff61507fa8 CR3: 000000007506a000 CR4: 00000000003526f0

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/16 22:25 git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2f2f7eeef8b0 4f92358f .config console log report C ci-upstream-kasan-gce kernel BUG in pskb_expand_head
2026/10/10 15:18 upstream 3857c2fe5449 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce kernel BUG in pskb_expand_head
* Struck through repros no longer work on HEAD.