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
Fix commit: a8c695005bfe can: j1939: j1939_session_new(): fix skb reference counting
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-native-arm64-kvm ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu2-arm32]
First crash: 96d, last: 12d
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 (5)
Title Replies (including bot) Last reply
[PATCH net 15/15] can: j1939: j1939_session_new(): fix skb reference counting 1 (1) 2024/12/02 08:55
[PATCH v2] can: fix skb reference counting in j1939_session_new() 11 (11) 2024/11/29 13:25
[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 (8107):
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
2024/11/26 03:37 upstream 2c22dc1ee3a1 11dbc254 .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
2024/11/04 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
2024/12/06 14:08 upstream 5076001689e4 946d28f0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 12:50 upstream 5076001689e4 946d28f0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 07:39 upstream 5076001689e4 946d28f0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 04:46 upstream 5076001689e4 946d28f0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 10:27 upstream 5076001689e4 946d28f0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 02:39 upstream 5076001689e4 946d28f0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 08:49 upstream 5076001689e4 946d28f0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 04:49 upstream 5076001689e4 946d28f0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: refcount bug in sk_skb_reason_drop
2024/12/05 00:02 upstream feffde684ac2 b50eb251 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING: refcount bug in sk_skb_reason_drop
2024/12/02 08:23 upstream f788b5ef1ca9 68914665 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/01 19:33 upstream bcc8eda6d349 68914665 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING: refcount bug in sk_skb_reason_drop
2024/12/09 13:15 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/09 10:47 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/09 07:08 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/09 00:38 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/08 22:45 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/08 21:17 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/08 21:14 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/08 19:31 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/08 17:34 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/08 12:55 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/08 08:49 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/08 08:22 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/08 06:45 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/08 03:53 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/08 01:48 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/08 00:58 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 22:43 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 22:32 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 21:22 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 20:01 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 15:43 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 13:22 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 12:22 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 08:25 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 08:21 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 06:34 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 05:34 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 05:31 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 03:02 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/07 00:11 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 20:44 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 20:42 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 19:15 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 18:13 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 18:05 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 16:36 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 12:34 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 946d28f0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in sk_skb_reason_drop
2024/12/06 03:41 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7b1d1d4cfac0 946d28f0 .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.