syzbot


WARNING: refcount bug in sk_skb_reason_drop

Status: upstream: reported C repro on 2024/10/03 16:14
Subsystems: can
[Documentation on labels]
Reported-by: syzbot+d4e8dc385d9258220c31@syzkaller.appspotmail.com
First crash: 66d, last: 1h09m
Cause bisection: introduced by (bisect log) :
commit c9c0ee5f20c593faf289fa8850c3ed84031dd12a
Author: Breno Leitao <leitao@debian.org>
Date: Mon Jul 29 10:47:40 2024 +0000

  net: skbuff: Skip early return in skb_unref when debugging

Crash: WARNING: refcount bug in j1939_session_destroy (log)
Repro: C syz .config
  
Discussions (4)
Title Replies (including bot) Last reply
[PATCH v2] can: fix skb reference counting in j1939_session_new() 6 (6) 2024/11/06 14:42
[syzbot] Monthly can report (Nov 2024) 0 (1) 2024/11/04 08:50
[syzbot] Monthly can report (Oct 2024) 0 (1) 2024/10/04 10:11
[syzbot] [can?] WARNING: refcount bug in sk_skb_reason_drop 1 (4) 2024/10/04 00:41
Last patch testing requests (2)
Created Duration User Patch Repo Result
2024/10/03 23:35 1h04m hdanton@sina.com patch upstream OK log
2024/10/03 17:39 28m dmantipov@yandex.ru patch git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 7ec462100ef9142344ddbf86f2c3008b97acddbe OK log

Sample crash report:
vxcan1: j1939_tp_rxtimer: 0xffff8880326cb400: rx timeout, send abort
vxcan1: j1939_xtp_rx_abort_one: 0xffff8880326cb400: 0x00000: (3) A timeout occurred and this is the connection abort to close the session.
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 16 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.11.0-syzkaller-02574-ga430d95c5efa #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Code: ff 89 de e8 58 80 04 fd 84 db 0f 85 66 ff ff ff e8 6b 7e 04 fd c6 05 59 3d 7f 0b 01 90 48 c7 c7 00 ba b0 8b e8 67 d1 c6 fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 48 7e 04 fd 0f b6 1d 34 3d 7f 0b 31
RSP: 0018:ffffc900001577c8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff814e2c79
RDX: ffff88801cadda00 RSI: ffffffff814e2c86 RDI: 0000000000000001
RBP: ffff88802e405224 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: ffff88802e405224 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b8800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055772d12ee40 CR3: 000000002853a000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 __refcount_sub_and_test include/linux/refcount.h:275 [inline]
 __refcount_dec_and_test include/linux/refcount.h:307 [inline]
 refcount_dec_and_test include/linux/refcount.h:325 [inline]
 skb_unref include/linux/skbuff.h:1232 [inline]
 __sk_skb_reason_drop net/core/skbuff.c:1213 [inline]
 sk_skb_reason_drop+0x183/0x1a0 net/core/skbuff.c:1241
 kfree_skb_reason include/linux/skbuff.h:1262 [inline]
 kfree_skb include/linux/skbuff.h:1271 [inline]
 j1939_session_destroy+0x163/0x460 net/can/j1939/transport.c:282
 __j1939_session_release net/can/j1939/transport.c:294 [inline]
 kref_put include/linux/kref.h:65 [inline]
 j1939_session_put net/can/j1939/transport.c:299 [inline]
 j1939_xtp_rx_abort_one+0x3f9/0x560 net/can/j1939/transport.c:1354
 j1939_xtp_rx_abort net/can/j1939/transport.c:1362 [inline]
 j1939_tp_cmd_recv net/can/j1939/transport.c:2128 [inline]
 j1939_tp_recv+0xcf8/0xf50 net/can/j1939/transport.c:2161
 j1939_can_recv+0x78f/0xa50 net/can/j1939/main.c:108
 deliver net/can/af_can.c:572 [inline]
 can_rcv_filter+0x2ab/0x900 net/can/af_can.c:606
 can_receive+0x320/0x5c0 net/can/af_can.c:663
 can_rcv+0x1e2/0x280 net/can/af_can.c:687
 __netif_receive_skb_one_core+0x1b4/0x1e0 net/core/dev.c:5662
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5775
 process_backlog+0x443/0x15f0 net/core/dev.c:6107
 __napi_poll.constprop.0+0xba/0x550 net/core/dev.c:6771
 napi_poll net/core/dev.c:6840 [inline]
 net_rx_action+0xa92/0x1010 net/core/dev.c:6962
 handle_softirqs+0x219/0x8f0 kernel/softirq.c:554
 run_ksoftirqd kernel/softirq.c:928 [inline]
 run_ksoftirqd+0x3a/0x60 kernel/softirq.c:920
 smpboot_thread_fn+0x664/0xa10 kernel/smpboot.c:164
 kthread+0x2c4/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (6277):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/19 10:29 upstream a430d95c5efa c673ca06 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/04 04:32 upstream a33ab3f94f51 f00eed24 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/03 23:23 upstream a33ab3f94f51 f00eed24 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/10/23 23:34 upstream c2ee9f594da8 15fa2979 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/10/03 19:39 upstream 7ec462100ef9 d7906eff .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/09/16 18:03 upstream adfc3ded5c33 49cf0773 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/21 05:37 upstream 43fb83c17ba2 4b25d554 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 23:49 upstream bf9aa14fc523 4fca1650 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 18:05 upstream bf9aa14fc523 4fca1650 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 00:08 upstream 158f238aa69d 571351cb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/19 20:03 upstream 158f238aa69d 571351cb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/19 11:22 upstream c6d64479d609 571351cb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/19 07:11 upstream c6d64479d609 571351cb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/19 06:08 upstream c6d64479d609 571351cb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 21:41 upstream adc218676eef 571351cb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 17:20 upstream adc218676eef 571351cb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 06:57 upstream f66d6acccbc0 cfe3a04a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 01:42 upstream f66d6acccbc0 cfe3a04a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/17 22:00 upstream f66d6acccbc0 cfe3a04a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/17 20:19 upstream f66d6acccbc0 cfe3a04a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING: refcount bug in sk_skb_reason_drop
2024/11/21 02:39 upstream 8f7c8b88bda4 4b25d554 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/21 02:38 upstream 8f7c8b88bda4 4b25d554 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 19:43 upstream 8f7c8b88bda4 4fca1650 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 13:18 upstream bf9aa14fc523 4fca1650 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 12:18 upstream bf9aa14fc523 4fca1650 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 11:33 upstream bf9aa14fc523 7d02db5a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/19 19:00 upstream 158f238aa69d 7d02db5a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/19 16:02 upstream 158f238aa69d 7d02db5a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/19 07:48 upstream 9fb2cfa4635a 571351cb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 23:07 upstream 9fb2cfa4635a 571351cb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 20:36 upstream adc218676eef e7bb5d6e .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 11:06 upstream adc218676eef e7bb5d6e .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 08:25 upstream adc218676eef cfe3a04a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/11/21 01:03 upstream 43fb83c17ba2 4b25d554 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 21:41 upstream bf9aa14fc523 4fca1650 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 21:41 upstream bf9aa14fc523 4fca1650 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 10:03 upstream d8d78a90e7fc 4dfba277 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 06:18 upstream bf9aa14fc523 7d02db5a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 04:20 upstream 158f238aa69d 7d02db5a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: refcount bug in sk_skb_reason_drop
2024/11/19 15:08 upstream 158f238aa69d 571351cb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: refcount bug in sk_skb_reason_drop
2024/11/19 12:41 upstream 158f238aa69d 571351cb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: refcount bug in sk_skb_reason_drop
2024/11/19 09:05 upstream 23acd177540d 4dfba277 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING: refcount bug in sk_skb_reason_drop
2024/11/19 05:30 upstream 9fb2cfa4635a 571351cb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: refcount bug in sk_skb_reason_drop
2024/11/19 02:38 upstream 9fb2cfa4635a 571351cb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 23:05 upstream 9fb2cfa4635a 571351cb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 18:49 upstream adc218676eef 4dfba277 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 18:05 upstream adc218676eef 4dfba277 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 13:45 upstream adc218676eef 4dfba277 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 10:59 upstream adc218676eef e7bb5d6e .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 00:20 upstream 4a5df3796467 4dfba277 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 15:41 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 4fca1650 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/11/20 03:10 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 7d02db5a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/11/19 21:10 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 571351cb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 15:27 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 571351cb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 06:57 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 887407160d72 cfe3a04a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/11/18 03:16 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 887407160d72 cfe3a04a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
* Struck through repros no longer work on HEAD.