All of lore.kernel.org
 help / color / mirror / Atom feed
From: syzbot <syzbot+9917f000776fb73fa40f@syzkaller.appspotmail.com>
To: alsa-devel@alsa-project.org, colin.king@canonical.com,
	linux-kernel@vger.kernel.org, perex@perex.cz,
	syzkaller-bugs@googlegroups.com, tiwai@suse.com
Subject: KASAN: use-after-free Read in delete_and_unsubscribe_port
Date: Sat, 29 Dec 2018 09:54:03 -0800	[thread overview]
Message-ID: <000000000000852fcf057e2cdd51@google.com> (raw)

Hello,

syzbot found the following crash on:

HEAD commit:    8fe28cb58bcb Linux 4.20
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=166859b3400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7d581260bae0899a
dashboard link: https://syzkaller.appspot.com/bug?extid=9917f000776fb73fa40f
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+9917f000776fb73fa40f@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:191  
[inline]
BUG: KASAN: use-after-free in list_empty include/linux/list.h:226 [inline]
BUG: KASAN: use-after-free in delete_and_unsubscribe_port+0x5d7/0x6d0  
sound/core/seq/seq_ports.c:548
Read of size 8 at addr ffff8881d1c05590 by task syz-executor1/6930

CPU: 0 PID: 6930 Comm: syz-executor1 Not tainted 4.20.0 #167
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+0x1d3/0x2c6 lib/dump_stack.c:113
  print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
  kasan_report_error mm/kasan/report.c:354 [inline]
  kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
  __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
  __read_once_size include/linux/compiler.h:191 [inline]
  list_empty include/linux/list.h:226 [inline]
  delete_and_unsubscribe_port+0x5d7/0x6d0 sound/core/seq/seq_ports.c:548
  snd_seq_port_disconnect+0x17b/0x280 sound/core/seq/seq_ports.c:628
  snd_seq_ioctl_unsubscribe_port+0x1d8/0x310  
sound/core/seq/seq_clientmgr.c:1499
  snd_seq_ioctl+0x253/0x440 sound/core/seq/seq_clientmgr.c:2138
  vfs_ioctl fs/ioctl.c:46 [inline]
  file_ioctl fs/ioctl.c:509 [inline]
  do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
  ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
  __do_sys_ioctl fs/ioctl.c:720 [inline]
  __se_sys_ioctl fs/ioctl.c:718 [inline]
  __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457759
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f36626cac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457759
RDX: 00000000200001c0 RSI: 0000000040505331 RDI: 0000000000000003
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f36626cb6d4
R13: 00000000004ca358 R14: 00000000004d35d0 R15: 00000000ffffffff

Allocated by task 6924:
  save_stack+0x43/0xd0 mm/kasan/kasan.c:448
  set_track mm/kasan/kasan.c:460 [inline]
  kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
  kmem_cache_alloc_trace+0x152/0x750 mm/slab.c:3620
  kmalloc include/linux/slab.h:546 [inline]
  kzalloc include/linux/slab.h:741 [inline]
  snd_seq_port_connect+0xe0/0x760 sound/core/seq/seq_ports.c:571
  snd_seq_ioctl_subscribe_port+0x1d8/0x310  
sound/core/seq/seq_clientmgr.c:1458
  snd_seq_ioctl+0x253/0x440 sound/core/seq/seq_clientmgr.c:2138
  vfs_ioctl fs/ioctl.c:46 [inline]
  file_ioctl fs/ioctl.c:509 [inline]
  do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
  ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
  __do_sys_ioctl fs/ioctl.c:720 [inline]
  __se_sys_ioctl fs/ioctl.c:718 [inline]
  __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 6931:
  save_stack+0x43/0xd0 mm/kasan/kasan.c:448
  set_track mm/kasan/kasan.c:460 [inline]
  __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
  kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
  __cache_free mm/slab.c:3498 [inline]
  kfree+0xcf/0x230 mm/slab.c:3817
  snd_seq_port_disconnect+0x205/0x280 sound/core/seq/seq_ports.c:632
  snd_seq_ioctl_unsubscribe_port+0x1d8/0x310  
sound/core/seq/seq_clientmgr.c:1499
  snd_seq_ioctl+0x253/0x440 sound/core/seq/seq_clientmgr.c:2138
  vfs_ioctl fs/ioctl.c:46 [inline]
  file_ioctl fs/ioctl.c:509 [inline]
  do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
  ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
  __do_sys_ioctl fs/ioctl.c:720 [inline]
  __se_sys_ioctl fs/ioctl.c:718 [inline]
  __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881d1c05540
  which belongs to the cache kmalloc-128 of size 128
The buggy address is located 80 bytes inside of
  128-byte region [ffff8881d1c05540, ffff8881d1c055c0)
The buggy address belongs to the page:
page:ffffea0007470140 count:1 mapcount:0 mapping:ffff8881da800640  
index:0xffff8881d1c05b40
flags: 0x2fffc0000000200(slab)
raw: 02fffc0000000200 ffffea0006fb09c8 ffffea0006f38908 ffff8881da800640
raw: ffff8881d1c05b40 ffff8881d1c05000 000000010000000e 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff8881d1c05480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff8881d1c05500: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
> ffff8881d1c05580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                          ^
  ffff8881d1c05600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff8881d1c05680: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with  
syzbot.

                 reply	other threads:[~2018-12-29 17:54 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=000000000000852fcf057e2cdd51@google.com \
    --to=syzbot+9917f000776fb73fa40f@syzkaller.appspotmail.com \
    --cc=alsa-devel@alsa-project.org \
    --cc=colin.king@canonical.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=perex@perex.cz \
    --cc=syzkaller-bugs@googlegroups.com \
    --cc=tiwai@suse.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.