syzbot

 sign-in | mailing list | source | docs
🐞 Open [994] ≡ Subsystems 🐞 Fixed [5242] 🐞 Invalid [12515] ⬇ Missing Backports [83] 📈 Kernel Health 📈 Bug Lifetimes 📈 Fuzzing 📈 Crashes 💬 Send us feedback

KASAN: invalid-free in snd_seq_port_disconnect

Status: fixed on 2020/09/16 22:51
Subsystems: sound
[Documentation on labels]
Reported-by: syzbot+9d2abfef257f3e2d4713@syzkaller.appspotmail.com
Fix commit: 80982c7e834e ALSA: seq: oss: Serialize ioctls
First crash: 1366d, last: 1361d
Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: WARNING in sysfs_warn_dup (log)
Repro: syz .config
  
▶ ▼ Discussions (9)
Title Replies (including bot) Last reply
[PATCH 4.4 000/149] 4.4.233-rc1 review 163 (163) 2020/10/31 20:04
[PATCH 4.9 000/212] 4.9.233-rc1 review 220 (220) 2020/08/21 09:40
[PATCH 4.14 000/228] 4.14.194-rc1 review 234 (234) 2020/08/21 06:59
[PATCH 4.19 00/48] 4.19.139-rc1 review 61 (61) 2020/08/11 16:45
[PATCH 5.8 00/38] 5.8.1-rc1 review 46 (46) 2020/08/11 16:20
[PATCH 5.7 00/79] 5.7.15-rc1 review 83 (83) 2020/08/11 14:23
[PATCH 5.4 00/67] 5.4.58-rc1 review 71 (71) 2020/08/11 14:23
Re: KASAN: invalid-free in snd_seq_port_disconnect 1 (1) 2020/07/31 11:58
KASAN: invalid-free in snd_seq_port_disconnect 0 (1) 2020/07/30 05:53
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2020/08/04 12:08 16m tiwai@suse.de git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git test/seq-oss-serialize OK

Sample crash report:
==================================================================
BUG: KASAN: double-free or invalid-free in snd_seq_port_disconnect+0x4c1/0x5c0 sound/core/seq/seq_ports.c:614

CPU: 0 PID: 7168 Comm: syz-executor.0 Not tainted 5.8.0-rc7-syzkaller #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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x436 mm/kasan/report.c:383
 kasan_report_invalid_free+0x51/0x80 mm/kasan/report.c:477
 __kasan_slab_free+0x127/0x140 mm/kasan/common.c:434
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x103/0x2c0 mm/slab.c:3757
 snd_seq_port_disconnect+0x4c1/0x5c0 sound/core/seq/seq_ports.c:614
 snd_seq_ioctl_unsubscribe_port+0x1fc/0x400 sound/core/seq/seq_clientmgr.c:1525
 snd_seq_kernel_client_ctl+0xeb/0x130 sound/core/seq/seq_clientmgr.c:2353
 snd_seq_oss_midi_close+0x36e/0x4d0 sound/core/seq/oss/seq_oss_midi.c:405
 snd_seq_oss_synth_reset+0x418/0x860 sound/core/seq/oss/seq_oss_synth.c:406
 snd_seq_oss_reset+0x6f/0x290 sound/core/seq/oss/seq_oss_init.c:435
 snd_seq_oss_ioctl+0xb7b/0xd40 sound/core/seq/oss/seq_oss_ioctl.c:93
 odev_ioctl+0x4f/0x90 sound/core/seq/oss/seq_oss.c:174
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:753
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl fs/ioctl.c:760 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cc79
Code: 2d b6 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f8e9ed59c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000000154c0 RCX: 000000000045cc79
RDX: 0000000000000000 RSI: 0000000000005100 RDI: 0000000000000003
RBP: 000000000078bfd8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bfac
R13: 00007ffc4facbfaf R14: 00007f8e9ed5a9c0 R15: 000000000078bfac

Allocated by task 7167:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
 kmem_cache_alloc_trace+0x14f/0x2d0 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 snd_seq_port_connect+0x5d/0x520 sound/core/seq/seq_ports.c:553
 snd_seq_ioctl_subscribe_port+0x1fc/0x400 sound/core/seq/seq_clientmgr.c:1484
 snd_seq_kernel_client_ctl+0xeb/0x130 sound/core/seq/seq_clientmgr.c:2353
 snd_seq_oss_midi_open+0x466/0x6e0 sound/core/seq/oss/seq_oss_midi.c:364
 snd_seq_oss_synth_setup_midi+0x123/0x520 sound/core/seq/oss/seq_oss_synth.c:269
 snd_seq_oss_open+0x87e/0xa10 sound/core/seq/oss/seq_oss_init.c:261
 odev_open+0x6c/0x90 sound/core/seq/oss/seq_oss.c:125
 soundcore_open+0x445/0x600 sound/sound_core.c:593
 chrdev_open+0x266/0x770 fs/char_dev.c:414
 do_dentry_open+0x501/0x1290 fs/open.c:828
 do_open fs/namei.c:3243 [inline]
 path_openat+0x1bb9/0x2750 fs/namei.c:3360
 do_filp_open+0x17e/0x3c0 fs/namei.c:3387
 do_sys_openat2+0x16f/0x3b0 fs/open.c:1179
 do_sys_open fs/open.c:1195 [inline]
 __do_sys_openat fs/open.c:1209 [inline]
 __se_sys_openat fs/open.c:1204 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1204
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 7167:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x103/0x2c0 mm/slab.c:3757
 snd_seq_port_disconnect+0x4c1/0x5c0 sound/core/seq/seq_ports.c:614
 snd_seq_ioctl_unsubscribe_port+0x1fc/0x400 sound/core/seq/seq_clientmgr.c:1525
 snd_seq_kernel_client_ctl+0xeb/0x130 sound/core/seq/seq_clientmgr.c:2353
 snd_seq_oss_midi_close+0x36e/0x4d0 sound/core/seq/oss/seq_oss_midi.c:405
 snd_seq_oss_synth_reset+0x418/0x860 sound/core/seq/oss/seq_oss_synth.c:406
 snd_seq_oss_reset+0x6f/0x290 sound/core/seq/oss/seq_oss_init.c:435
 snd_seq_oss_ioctl+0xb7b/0xd40 sound/core/seq/oss/seq_oss_ioctl.c:93
 odev_ioctl+0x4f/0x90 sound/core/seq/oss/seq_oss.c:174
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:753
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl fs/ioctl.c:760 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8880a4b4c500
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 0 bytes inside of
 128-byte region [ffff8880a4b4c500, ffff8880a4b4c580)
The buggy address belongs to the page:
page:ffffea000292d300 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00029b0388 ffffea00028a04c8 ffff8880aa000700
raw: 0000000000000000 ffff8880a4b4c000 0000000100000010 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a4b4c400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a4b4c480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a4b4c500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8880a4b4c580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a4b4c600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/08/01 18:55 upstream 7dc6fd0f3b84 d895b3be .config console log report syz ci-upstream-kasan-gce-root
2020/08/01 17:04 upstream 7dc6fd0f3b84 d895b3be .config console log report syz ci-upstream-kasan-gce-root
2020/08/01 15:13 upstream 7dc6fd0f3b84 d895b3be .config console log report syz ci-upstream-kasan-gce-root
2020/07/31 12:47 upstream 83bdc7275e62 8df85ed9 .config console log report syz ci-upstream-kasan-gce-selinux-root
2020/07/31 12:26 upstream 83bdc7275e62 8df85ed9 .config console log report syz ci-upstream-kasan-gce-selinux-root
2020/07/31 12:12 upstream 83bdc7275e62 8df85ed9 .config console log report syz ci-upstream-kasan-gce-selinux-root
2020/07/30 03:50 upstream d3590ebf6f91 233283a1 .config console log report syz ci-upstream-kasan-gce-smack-root
2020/08/04 03:06 linux-next 01830e6c042e 196277c4 .config console log report syz ci-upstream-linux-next-kasan-gce-root
2020/08/04 01:16 linux-next 01830e6c042e 196277c4 .config console log report syz ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.