kernel BUG in cdc_ncm_fill_tx_frame (2)

Status: fixed on 2023/06/16 14:10
Bug presence: origin:downstream
[Documentation on labels]
Fix commit: 6a33db6d068c UPSTREAM: net: cdc_ncm: Deal with too low values of dwNtbOutMaxSize
First crash: 144d, last: 130d
Cause bisection: introduced by (bisect log) :
commit 3c55aa6ffeeff6673ab8077c0b9c0c46a4edd476
Author: Vignesh Saravanaperumal <>
Date: Thu Jul 8 14:01:33 2021 +0000

  ANDROID: GKI: add vendor padding variable in struct skb_shared_info

Crash: kernel BUG in cdc_ncm_fill_tx_frame (log)
Repro: C syz .config
Discussions (2)
Title Replies (including bot) Last reply
[PATCH][stable-4.{14,19}.y 0/3] net: cdc_ncm: Backport fixes 3 (3) 2023/06/07 18:15
[PATCH 1/1] net: cdc_ncm: Allow for dwNtbOutMaxSize to be unset or zero 14 (14) 2023/05/19 03:10
Bug presence (3)
Date Name Commit Repro Result
2023/05/10 android13-5.15-lts (ToT) 19c0ed55a470 C [report] kernel BUG in cdc_ncm_fill_tx_frame
2023/05/09 lts (merge base) d86dfc4d95cd C Didn't crash
2023/05/09 upstream (ToT) 16a8829130ca C Didn't crash
Similar bugs (7)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream kernel BUG in cdc_ncm_fill_tx_frame usb syz 4 6d06h 119d 0/25 upstream: reported syz repro on 2023/06/02 18:39
android-5-10 kernel BUG in add_grec C error 83 551d 624d 2/2 fixed on 2022/03/29 10:01
android-54 kernel BUG at net/core/skbuff.c:LINE! C 267 137d 1357d 0/2 auto-obsoleted due to no activity on 2023/08/22 15:17
android-5-10 kernel BUG in add_grec (2) C error inconclusive 1039 311d 311d 2/2 fixed on 2023/02/24 12:10
android-5-10 kernel BUG in cdc_ncm_fill_tx_frame C error 40 643d 708d 1/2 fixed on 2021/12/29 12:20
android-5-15 kernel BUG in cdc_ncm_fill_tx_frame 1 311d 311d 0/2 auto-obsoleted due to no activity on 2023/04/11 17:56
android-5-10 kernel BUG in cdc_ncm_fill_tx_frame (2) C error 3 136d 144d 2/2 fixed on 2023/06/28 00:02
Last patch testing requests (6)
Created Duration User Patch Repo Result
2023/05/17 13:00 18m cdc_ncm_fill_tx_frame2-bug OK log
2023/05/16 09:06 17m cdc_ncm_fill_tx_frame2-bug OK log
2023/05/15 14:39 10m cdc_ncm_fill_tx_frame2-bug report log
2023/05/15 14:12 0m patch 19c0ed55a470d1cd766484abab04871b648560fb error OK
2023/05/15 11:16 36m 19c0ed55a470d1cd766484abab04871b648560fb report log
2023/05/09 07:34 17m git:// linux-5.15.y OK log

Sample crash report:
IPv6: ADDRCONF(NETDEV_CHANGE): usb0: link becomes ready
skbuff: skb_over_panic: text:ffffffff831f755b len:184 put:172 head:ffff88811f1c6c00 data:ffff88811f1c6c00 tail:0xb8 end:0x80 dev:<NULL>
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:113!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 57 Comm: kworker/0:2 Not tainted 5.15.106-syzkaller-00249-g19c0ed55a470 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Workqueue: mld mld_ifc_work
RIP: 0010:skb_panic net/core/skbuff.c:113 [inline]
RIP: 0010:skb_over_panic+0x14c/0x150 net/core/skbuff.c:118
Code: c0 c6 b1 85 48 c7 c6 b0 6f fd 85 48 8b 55 c0 8b 4d d4 44 8b 45 d0 4c 8b 4d c8 53 41 55 41 54 41 57 e8 ad 02 dd 00 48 83 c4 20 <0f> 0b 66 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 ec 10 89
RSP: 0018:ffffc900008d6f80 EFLAGS: 00010282
RAX: 0000000000000087 RBX: ffffffff85b1c740 RCX: 3b464bf4c86e1400
RDX: 0000000000000000 RSI: 0000000080000603 RDI: 0000000000000000
RBP: ffffc900008d6fc0 R08: ffffffff815748e5 R09: ffffed103ee065e8
R10: 0000000000000000 R11: dffffc0000000001 R12: 00000000000000b8
R13: 0000000000000080 R14: dffffc0000000000 R15: ffff88811f1c6c00
FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d06720e000 CR3: 0000000115e8d000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 skb_put+0x151/0x210 net/core/skbuff.c:2047
 skb_put_zero include/linux/skbuff.h:2422 [inline]
 cdc_ncm_ndp16 drivers/net/usb/cdc_ncm.c:1131 [inline]
 cdc_ncm_fill_tx_frame+0x11ab/0x3da0 drivers/net/usb/cdc_ncm.c:1308
 usbnet_start_xmit+0x118/0x1b60 drivers/net/usb/usbnet.c:1368
 __netdev_start_xmit include/linux/netdevice.h:5059 [inline]
 netdev_start_xmit include/linux/netdevice.h:5073 [inline]
 xmit_one net/core/dev.c:3599 [inline]
 dev_hard_start_xmit+0x228/0x620 net/core/dev.c:3615
 sch_direct_xmit+0x298/0x9b0 net/sched/sch_generic.c:342
 __dev_xmit_skb net/core/dev.c:3826 [inline]
 __dev_queue_xmit+0x161e/0x2e70 net/core/dev.c:4195
 dev_queue_xmit+0x17/0x20 net/core/dev.c:4263
 neigh_resolve_output+0x6b8/0x760 net/core/neighbour.c:1524
 neigh_output include/net/neighbour.h:524 [inline]
 ip6_finish_output2+0xf95/0x16e0 net/ipv6/ip6_output.c:126
 __ip6_finish_output+0x678/0x850 net/ipv6/ip6_output.c:191
 ip6_finish_output+0x31/0x210 net/ipv6/ip6_output.c:201
 NF_HOOK_COND include/linux/netfilter.h:299 [inline]
 ip6_output+0x1f7/0x4d0 net/ipv6/ip6_output.c:224
 dst_output include/net/dst.h:450 [inline]
 NF_HOOK include/linux/netfilter.h:310 [inline]
 mld_sendpack+0x662/0xbb0 net/ipv6/mcast.c:1820
 mld_send_cr net/ipv6/mcast.c:2121 [inline]
 mld_ifc_work+0x7dc/0xbb0 net/ipv6/mcast.c:2653
 process_one_work+0x6bb/0xc10 kernel/workqueue.c:2313
 worker_thread+0xad5/0x12a0 kernel/workqueue.c:2460
 kthread+0x421/0x510 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
Modules linked in:

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/05/09 02:31 android13-5.15-lts 19c0ed55a470 c7a5e2a0 .config strace log report syz C [disk image] [vmlinux] [kernel image] ci2-android-5-15 kernel BUG in cdc_ncm_fill_tx_frame
2023/05/23 15:33 android13-5.15-lts 19c0ed55a470 4bce1a3e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 kernel BUG in cdc_ncm_fill_tx_frame
2023/05/22 14:53 android13-5.15-lts 19c0ed55a470 4bce1a3e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 kernel BUG in cdc_ncm_fill_tx_frame
2023/05/16 09:29 android13-5.15-lts 19c0ed55a470 71b00cfb .config console log report info ci2-android-5-15 kernel BUG in cdc_ncm_fill_tx_frame
2023/05/09 02:00 android13-5.15-lts 19c0ed55a470 c7a5e2a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 kernel BUG in cdc_ncm_fill_tx_frame
* Struck through repros no longer work on HEAD.