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Date:   Mon, 04 Nov 2019 20:22:09 -0800
Message-ID: <0000000000009393ba059691c6a3@google.com>
Subject: KASAN: use-after-free Read in j1939_session_get_by_addr
From:   syzbot <syzbot+d9536adc269404a984f8@syzkaller.appspotmail.com>
To:     davem@davemloft.net, kernel@pengutronix.de,
        linux-can@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux@rempel-privat.de, mkl@pengutronix.de, netdev@vger.kernel.org,
        robin@protonic.nl, socketcan@hartkopp.net,
        syzkaller-bugs@googlegroups.com
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Sender: linux-kernel-owner@vger.kernel.org
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Hello,

syzbot found the following crash on:

HEAD commit:    a99d8080 Linux 5.4-rc6
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14d0cc58e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8c5e2eca3f31f9bf
dashboard link: https://syzkaller.appspot.com/bug?extid=d9536adc269404a984f8
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1796b4dce00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=142798dce00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+d9536adc269404a984f8@syzkaller.appspotmail.com

vcan0: j1939_xtp_rx_abort_one: 0x00000000a2ba57cc: 0x00000: (3) A timeout  
occurred and this is the connection abort to close the session.
vcan0: j1939_xtp_rx_abort_one: 0x00000000f495a5ef: 0x00000: (3) A timeout  
occurred and this is the connection abort to close the session.
==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x3a8b/0x4a00  
kernel/locking/lockdep.c:3828
Read of size 8 at addr ffff888094225080 by task ksoftirqd/0/9

CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.4.0-rc6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x172/0x1f0 lib/dump_stack.c:113
  print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
  __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
  kasan_report+0x12/0x20 mm/kasan/common.c:634
  __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
  __lock_acquire+0x3a8b/0x4a00 kernel/locking/lockdep.c:3828
  lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4487
  __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
  _raw_spin_lock_bh+0x33/0x50 kernel/locking/spinlock.c:175
  spin_lock_bh include/linux/spinlock.h:343 [inline]
  j1939_session_list_lock net/can/j1939/transport.c:238 [inline]
  j1939_session_get_by_addr+0x2d/0x60 net/can/j1939/transport.c:530
  j1939_xtp_rx_abort_one+0x8d/0x100 net/can/j1939/transport.c:1242
  j1939_xtp_rx_abort net/can/j1939/transport.c:1270 [inline]
  j1939_tp_cmd_recv net/can/j1939/transport.c:1943 [inline]
  j1939_tp_recv+0x513/0x9b0 net/can/j1939/transport.c:1973
  j1939_can_recv+0x4bb/0x620 net/can/j1939/main.c:100
  deliver net/can/af_can.c:568 [inline]
  can_rcv_filter+0x292/0x8e0 net/can/af_can.c:602
  can_receive+0x2e7/0x530 net/can/af_can.c:659
  can_rcv+0x133/0x1b0 net/can/af_can.c:685
  __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:4929
  __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5043
  process_backlog+0x206/0x750 net/core/dev.c:5874
  napi_poll net/core/dev.c:6311 [inline]
  net_rx_action+0x508/0x1120 net/core/dev.c:6379
  __do_softirq+0x262/0x98c kernel/softirq.c:292
  run_ksoftirqd kernel/softirq.c:603 [inline]
  run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595
  smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165
  kthread+0x361/0x430 kernel/kthread.c:255
  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 9736:
  save_stack+0x23/0x90 mm/kasan/common.c:69
  set_track mm/kasan/common.c:77 [inline]
  __kasan_kmalloc mm/kasan/common.c:510 [inline]
  __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:483
  kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524
  kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3550
  kmalloc include/linux/slab.h:556 [inline]
  kzalloc include/linux/slab.h:690 [inline]
  j1939_priv_create net/can/j1939/main.c:122 [inline]
  j1939_netdev_start+0xa4/0x550 net/can/j1939/main.c:251
  j1939_sk_bind+0x65a/0x8e0 net/can/j1939/socket.c:438
  __sys_bind+0x239/0x290 net/socket.c:1647
  __do_sys_bind net/socket.c:1658 [inline]
  __se_sys_bind net/socket.c:1656 [inline]
  __x64_sys_bind+0x73/0xb0 net/socket.c:1656
  do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9:
  save_stack+0x23/0x90 mm/kasan/common.c:69
  set_track mm/kasan/common.c:77 [inline]
  kasan_set_free_info mm/kasan/common.c:332 [inline]
  __kasan_slab_free+0x102/0x150 mm/kasan/common.c:471
  kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
  __cache_free mm/slab.c:3425 [inline]
  kfree+0x10a/0x2c0 mm/slab.c:3756
  __j1939_priv_release net/can/j1939/main.c:154 [inline]
  kref_put include/linux/kref.h:65 [inline]
  j1939_priv_put+0x8b/0xb0 net/can/j1939/main.c:159
  j1939_session_destroy net/can/j1939/transport.c:271 [inline]
  __j1939_session_release net/can/j1939/transport.c:280 [inline]
  kref_put include/linux/kref.h:65 [inline]
  j1939_session_put+0x12c/0x180 net/can/j1939/transport.c:285
  j1939_xtp_rx_abort_one+0xc7/0x100 net/can/j1939/transport.c:1261
  j1939_xtp_rx_abort net/can/j1939/transport.c:1269 [inline]
  j1939_tp_cmd_recv net/can/j1939/transport.c:1943 [inline]
  j1939_tp_recv+0x4fb/0x9b0 net/can/j1939/transport.c:1973
  j1939_can_recv+0x4bb/0x620 net/can/j1939/main.c:100
  deliver net/can/af_can.c:568 [inline]
  can_rcv_filter+0x292/0x8e0 net/can/af_can.c:602
  can_receive+0x2e7/0x530 net/can/af_can.c:659
  can_rcv+0x133/0x1b0 net/can/af_can.c:685
  __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:4929
  __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5043
  process_backlog+0x206/0x750 net/core/dev.c:5874
  napi_poll net/core/dev.c:6311 [inline]
  net_rx_action+0x508/0x1120 net/core/dev.c:6379
  __do_softirq+0x262/0x98c kernel/softirq.c:292

The buggy address belongs to the object at ffff888094224000
  which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 4224 bytes inside of
  8192-byte region [ffff888094224000, ffff888094226000)
The buggy address belongs to the page:
page:ffffea0002508900 refcount:1 mapcount:0 mapping:ffff8880aa4021c0  
index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea000252a808 ffffea000232f808 ffff8880aa4021c0
raw: 0000000000000000 ffff888094224000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff888094224f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff888094225000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff888094225080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                    ^
  ffff888094225100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff888094225180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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