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Groups > linux.kernel > #1325613 > unrolled thread

sound: use-after-free in snd_timer_start1

Started byDmitry Vyukov <dvyukov@google.com>
First post2016-02-03 17:30 +0100
Last post2016-02-04 17:40 +0100
Articles 4 — 2 participants

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Contents

  sound: use-after-free in snd_timer_start1 Dmitry Vyukov <dvyukov@google.com> - 2016-02-03 17:30 +0100
    Re: sound: use-after-free in snd_timer_start1 Takashi Iwai <tiwai@suse.de> - 2016-02-04 17:30 +0100
      Re: sound: use-after-free in snd_timer_start1 Dmitry Vyukov <dvyukov@google.com> - 2016-02-04 17:40 +0100
        Re: sound: use-after-free in snd_timer_start1 Takashi Iwai <tiwai@suse.de> - 2016-02-04 17:40 +0100

#1325613 — sound: use-after-free in snd_timer_start1

FromDmitry Vyukov <dvyukov@google.com>
Date2016-02-03 17:30 +0100
Subjectsound: use-after-free in snd_timer_start1
Message-ID<qY8tA-4kE-7@gated-at.bofh.it>
Hello,

The following program triggers use-after-free in snd_timer_start1:

// autogenerated by syzkaller (http://github.com/google/syzkaller)
#include <pthread.h>
#include <stdint.h>
#include <string.h>
#include <sys/syscall.h>
#include <unistd.h>

int main()
{
  syscall(SYS_mmap, 0x20000000ul, 0x664000ul, 0x3ul, 0x32ul,
          0xfffffffffffffffful, 0x0ul);
  int fd = syscall(SYS_open, "/dev/snd/timer", 0x40000ul, 0, 0, 0);
  *(uint32_t*)0x20653000 = (uint32_t)0x1;
  *(uint32_t*)0x20653004 = (uint32_t)0xfffffffffffffffe;
  *(uint32_t*)0x20653008 = (uint32_t)0x8;
  *(uint32_t*)0x2065300c = (uint32_t)0x0;
  *(uint32_t*)0x20653010 = (uint32_t)0x0;
  *(uint8_t*)0x20653014 = (uint8_t)0x0;
  *(uint8_t*)0x20653015 = (uint8_t)0x0;
  *(uint8_t*)0x20653016 = (uint8_t)0x0;
  *(uint8_t*)0x20653017 = (uint8_t)0x0;
  *(uint8_t*)0x20653018 = (uint8_t)0x0;
  *(uint8_t*)0x20653019 = (uint8_t)0x0;
  *(uint8_t*)0x2065301a = (uint8_t)0x0;
  *(uint8_t*)0x2065301b = (uint8_t)0x0;
  *(uint8_t*)0x2065301c = (uint8_t)0x0;
  *(uint8_t*)0x2065301d = (uint8_t)0x0;
  *(uint8_t*)0x2065301e = (uint8_t)0x0;
  *(uint8_t*)0x2065301f = (uint8_t)0x0;
  *(uint8_t*)0x20653020 = (uint8_t)0x0;
  *(uint8_t*)0x20653021 = (uint8_t)0x0;
  *(uint8_t*)0x20653022 = (uint8_t)0x0;
  *(uint8_t*)0x20653023 = (uint8_t)0x0;
  *(uint8_t*)0x20653024 = (uint8_t)0x0;
  *(uint8_t*)0x20653025 = (uint8_t)0x0;
  *(uint8_t*)0x20653026 = (uint8_t)0x0;
  *(uint8_t*)0x20653027 = (uint8_t)0x0;
  *(uint8_t*)0x20653028 = (uint8_t)0x0;
  *(uint8_t*)0x20653029 = (uint8_t)0x0;
  *(uint8_t*)0x2065302a = (uint8_t)0x0;
  *(uint8_t*)0x2065302b = (uint8_t)0x0;
  *(uint8_t*)0x2065302c = (uint8_t)0x0;
  *(uint8_t*)0x2065302d = (uint8_t)0x0;
  *(uint8_t*)0x2065302e = (uint8_t)0x0;
  *(uint8_t*)0x2065302f = (uint8_t)0x0;
  *(uint8_t*)0x20653030 = (uint8_t)0x0;
  *(uint8_t*)0x20653031 = (uint8_t)0x0;
  *(uint8_t*)0x20653032 = (uint8_t)0x0;
  *(uint8_t*)0x20653033 = (uint8_t)0x0;
  syscall(SYS_ioctl, fd, 0x40345410ul, 0x20653000ul, 0, 0, 0);
  syscall(SYS_ioctl, fd, 0x54a0ul, 0, 0, 0, 0);
  return 0;
}

==================================================================
BUG: KASAN: use-after-free in __list_add+0x233/0x22016/02/03 13:44:32
executing program 0:
Read of size 8 by task syz-executor/27661

INFO: Allocated in snd_timer_instance_new+0x52/0x3a0 age=7 cpu=0 pid=27660
[<     inline     >] slab_alloc_node mm/slub.c:2562
[<     inline     >] slab_alloc mm/slub.c:2604
[<      none      >] kmem_cache_alloc_trace+0x25c/0x300 mm/slub.c:2621
[<     inline     >] kmalloc include/linux/slab.h:463
[<     inline     >] kzalloc include/linux/slab.h:607
[<      none      >] snd_timer_instance_new+0x52/0x3a0 sound/core/timer.c:106
[<      none      >] snd_timer_open+0x522/0xd20 sound/core/timer.c:289
[<     inline     >] snd_timer_user_tselect sound/core/timer.c:1598
[<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1874
[<      none      >] snd_timer_user_ioctl+0x8db/0x25f0 sound/core/timer.c:1904
[<     inline     >] vfs_ioctl fs/ioctl.c:43
[<      none      >] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
[<     inline     >] SYSC_ioctl fs/ioctl.c:689
[<      none      >] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
[<      none      >] entry_SYSCALL_64_fastpath+0x16/0x7a
arch/x86/entry/entry_64.S:185

INFO: Freed in snd_timer_close+0x3ee/0x750 age=9 cpu=3 pid=27661
[<     inline     >] slab_free mm/slub.c:2835
[<      none      >] kfree+0x2ac/0x2c0 mm/slub.c:3664
[<      none      >] snd_timer_close+0x3ee/0x750 sound/core/timer.c:375
[<     inline     >] snd_timer_user_tselect sound/core/timer.c:1588
[<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1874
[<      none      >] snd_timer_user_ioctl+0x7b6/0x25f0 sound/core/timer.c:1904
[<     inline     >] vfs_ioctl fs/ioctl.c:43
[<      none      >] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
[<     inline     >] SYSC_ioctl fs/ioctl.c:689
[<      none      >] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
[<      none      >] entry_SYSCALL_64_fastpath+0x16/0x7a
arch/x86/entry/entry_64.S:185

Call Trace:
 [<     inline     >] kasan_report mm/kasan/report.c:274
 [<ffffffff8176640e>] __asan_report_load8_noabort+0x3e/0x40
mm/kasan/report.c:295
 [<ffffffff82c4a7e3>] __list_add+0x233/0x250 lib/list_debug.c:39
 [<     inline     >] list_move_tail include/linux/list.h:77
 [<ffffffff85240fdc>] snd_timer_start1+0x6c/0x2c0 sound/core/timer.c:432
 [<ffffffff85241a7b>] snd_timer_start+0x20b/0x2b0 sound/core/timer.c:499
 [<     inline     >] snd_timer_user_start sound/core/timer.c:1799
 [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1883
 [<ffffffff85245fb7>] snd_timer_user_ioctl+0x767/0x25f0 sound/core/timer.c:1904
 [<     inline     >] vfs_ioctl fs/ioctl.c:43
 [<ffffffff817fa9ec>] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
 [<     inline     >] SYSC_ioctl fs/ioctl.c:689
 [<ffffffff817fb89f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
 [<ffffffff8665ebb6>] entry_SYSCALL_64_fastpath+0x16/0x7a
arch/x86/entry/entry_64.S:185
==================================================================


Sometimes it manifests as:

------------[ cut here ]------------
WARNING: CPU: 1 PID: 6548 at lib/list_debug.c:42 __list_add+0x1db/0x250()
list_add corruption. prev->next should be next (ffff8800697c10e8), but
was ffff880030441fd0. (prev=ffff880030441fd0).
Modules linked in:
CPU: 1 PID: 6548 Comm: a.out Not tainted 4.5.0-rc2+ #309
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 00000000ffffffff ffff88002fa17918 ffffffff82be2c8d ffff88002fa17988
 ffff88002fd62f80 ffffffff86acf380 ffff88002fa17958 ffffffff81355139
 ffffffff82c4a78b ffffed0005f42f2d ffffffff86acf380 000000000000002a
Call Trace:
 [<     inline     >] __dump_stack lib/dump_stack.c:15
 [<ffffffff82be2c8d>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50
 [<ffffffff81355139>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482
 [<ffffffff81355249>] warn_slowpath_fmt+0xa9/0xd0 kernel/panic.c:494
 [<ffffffff82c4a78b>] __list_add+0x1db/0x250 lib/list_debug.c:39
 [<     inline     >] list_move_tail include/linux/list.h:77
 [<ffffffff85240fdc>] snd_timer_start1+0x6c/0x2c0 sound/core/timer.c:432
 [<ffffffff85241a7b>] snd_timer_start+0x20b/0x2b0 sound/core/timer.c:499
 [<     inline     >] snd_timer_user_start sound/core/timer.c:1799
 [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1883
 [<ffffffff85245fb7>] snd_timer_user_ioctl+0x767/0x25f0 sound/core/timer.c:1904
 [<     inline     >] vfs_ioctl fs/ioctl.c:43
 [<ffffffff817fa9ec>] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
 [<     inline     >] SYSC_ioctl fs/ioctl.c:689
 [<ffffffff817fb89f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
 [<ffffffff8665ebb6>] entry_SYSCALL_64_fastpath+0x16/0x7a
arch/x86/entry/entry_64.S:185
---[ end trace 77da812dd399e78b ]---

On commit 34229b277480f46c1e9a19f027f30b074512e68b + recent fixes from Takashi.

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#1326964

FromTakashi Iwai <tiwai@suse.de>
Date2016-02-04 17:30 +0100
Message-ID<qYuX8-4mU-15@gated-at.bofh.it>
In reply to#1325613
On Wed, 03 Feb 2016 17:24:56 +0100,
Dmitry Vyukov wrote:
> 
> Hello,
> 
> The following program triggers use-after-free in snd_timer_start1:
> 
> // autogenerated by syzkaller (http://github.com/google/syzkaller)
> #include <pthread.h>
> #include <stdint.h>
> #include <string.h>
> #include <sys/syscall.h>
> #include <unistd.h>
> 
> int main()
> {
>   syscall(SYS_mmap, 0x20000000ul, 0x664000ul, 0x3ul, 0x32ul,
>           0xfffffffffffffffful, 0x0ul);
>   int fd = syscall(SYS_open, "/dev/snd/timer", 0x40000ul, 0, 0, 0);
>   *(uint32_t*)0x20653000 = (uint32_t)0x1;
>   *(uint32_t*)0x20653004 = (uint32_t)0xfffffffffffffffe;
>   *(uint32_t*)0x20653008 = (uint32_t)0x8;
>   *(uint32_t*)0x2065300c = (uint32_t)0x0;
>   *(uint32_t*)0x20653010 = (uint32_t)0x0;
>   *(uint8_t*)0x20653014 = (uint8_t)0x0;
>   *(uint8_t*)0x20653015 = (uint8_t)0x0;
>   *(uint8_t*)0x20653016 = (uint8_t)0x0;
>   *(uint8_t*)0x20653017 = (uint8_t)0x0;
>   *(uint8_t*)0x20653018 = (uint8_t)0x0;
>   *(uint8_t*)0x20653019 = (uint8_t)0x0;
>   *(uint8_t*)0x2065301a = (uint8_t)0x0;
>   *(uint8_t*)0x2065301b = (uint8_t)0x0;
>   *(uint8_t*)0x2065301c = (uint8_t)0x0;
>   *(uint8_t*)0x2065301d = (uint8_t)0x0;
>   *(uint8_t*)0x2065301e = (uint8_t)0x0;
>   *(uint8_t*)0x2065301f = (uint8_t)0x0;
>   *(uint8_t*)0x20653020 = (uint8_t)0x0;
>   *(uint8_t*)0x20653021 = (uint8_t)0x0;
>   *(uint8_t*)0x20653022 = (uint8_t)0x0;
>   *(uint8_t*)0x20653023 = (uint8_t)0x0;
>   *(uint8_t*)0x20653024 = (uint8_t)0x0;
>   *(uint8_t*)0x20653025 = (uint8_t)0x0;
>   *(uint8_t*)0x20653026 = (uint8_t)0x0;
>   *(uint8_t*)0x20653027 = (uint8_t)0x0;
>   *(uint8_t*)0x20653028 = (uint8_t)0x0;
>   *(uint8_t*)0x20653029 = (uint8_t)0x0;
>   *(uint8_t*)0x2065302a = (uint8_t)0x0;
>   *(uint8_t*)0x2065302b = (uint8_t)0x0;
>   *(uint8_t*)0x2065302c = (uint8_t)0x0;
>   *(uint8_t*)0x2065302d = (uint8_t)0x0;
>   *(uint8_t*)0x2065302e = (uint8_t)0x0;
>   *(uint8_t*)0x2065302f = (uint8_t)0x0;
>   *(uint8_t*)0x20653030 = (uint8_t)0x0;
>   *(uint8_t*)0x20653031 = (uint8_t)0x0;
>   *(uint8_t*)0x20653032 = (uint8_t)0x0;
>   *(uint8_t*)0x20653033 = (uint8_t)0x0;
>   syscall(SYS_ioctl, fd, 0x40345410ul, 0x20653000ul, 0, 0, 0);
>   syscall(SYS_ioctl, fd, 0x54a0ul, 0, 0, 0, 0);
>   return 0;
> }
> 
> ==================================================================
> BUG: KASAN: use-after-free in __list_add+0x233/0x22016/02/03 13:44:32
> executing program 0:
> Read of size 8 by task syz-executor/27661
> 
> INFO: Allocated in snd_timer_instance_new+0x52/0x3a0 age=7 cpu=0 pid=27660
> [<     inline     >] slab_alloc_node mm/slub.c:2562
> [<     inline     >] slab_alloc mm/slub.c:2604
> [<      none      >] kmem_cache_alloc_trace+0x25c/0x300 mm/slub.c:2621
> [<     inline     >] kmalloc include/linux/slab.h:463
> [<     inline     >] kzalloc include/linux/slab.h:607
> [<      none      >] snd_timer_instance_new+0x52/0x3a0 sound/core/timer.c:106
> [<      none      >] snd_timer_open+0x522/0xd20 sound/core/timer.c:289
> [<     inline     >] snd_timer_user_tselect sound/core/timer.c:1598
> [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1874
> [<      none      >] snd_timer_user_ioctl+0x8db/0x25f0 sound/core/timer.c:1904
> [<     inline     >] vfs_ioctl fs/ioctl.c:43
> [<      none      >] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
> [<     inline     >] SYSC_ioctl fs/ioctl.c:689
> [<      none      >] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
> [<      none      >] entry_SYSCALL_64_fastpath+0x16/0x7a
> arch/x86/entry/entry_64.S:185
> 
> INFO: Freed in snd_timer_close+0x3ee/0x750 age=9 cpu=3 pid=27661
> [<     inline     >] slab_free mm/slub.c:2835
> [<      none      >] kfree+0x2ac/0x2c0 mm/slub.c:3664
> [<      none      >] snd_timer_close+0x3ee/0x750 sound/core/timer.c:375
> [<     inline     >] snd_timer_user_tselect sound/core/timer.c:1588
> [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1874
> [<      none      >] snd_timer_user_ioctl+0x7b6/0x25f0 sound/core/timer.c:1904
> [<     inline     >] vfs_ioctl fs/ioctl.c:43
> [<      none      >] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
> [<     inline     >] SYSC_ioctl fs/ioctl.c:689
> [<      none      >] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
> [<      none      >] entry_SYSCALL_64_fastpath+0x16/0x7a
> arch/x86/entry/entry_64.S:185
> 
> Call Trace:
>  [<     inline     >] kasan_report mm/kasan/report.c:274
>  [<ffffffff8176640e>] __asan_report_load8_noabort+0x3e/0x40
> mm/kasan/report.c:295
>  [<ffffffff82c4a7e3>] __list_add+0x233/0x250 lib/list_debug.c:39
>  [<     inline     >] list_move_tail include/linux/list.h:77
>  [<ffffffff85240fdc>] snd_timer_start1+0x6c/0x2c0 sound/core/timer.c:432
>  [<ffffffff85241a7b>] snd_timer_start+0x20b/0x2b0 sound/core/timer.c:499
>  [<     inline     >] snd_timer_user_start sound/core/timer.c:1799
>  [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1883
>  [<ffffffff85245fb7>] snd_timer_user_ioctl+0x767/0x25f0 sound/core/timer.c:1904
>  [<     inline     >] vfs_ioctl fs/ioctl.c:43
>  [<ffffffff817fa9ec>] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
>  [<     inline     >] SYSC_ioctl fs/ioctl.c:689
>  [<ffffffff817fb89f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
>  [<ffffffff8665ebb6>] entry_SYSCALL_64_fastpath+0x16/0x7a
> arch/x86/entry/entry_64.S:185
> ==================================================================
> 
> 
> Sometimes it manifests as:
> 
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 6548 at lib/list_debug.c:42 __list_add+0x1db/0x250()
> list_add corruption. prev->next should be next (ffff8800697c10e8), but
> was ffff880030441fd0. (prev=ffff880030441fd0).
> Modules linked in:
> CPU: 1 PID: 6548 Comm: a.out Not tainted 4.5.0-rc2+ #309
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
>  00000000ffffffff ffff88002fa17918 ffffffff82be2c8d ffff88002fa17988
>  ffff88002fd62f80 ffffffff86acf380 ffff88002fa17958 ffffffff81355139
>  ffffffff82c4a78b ffffed0005f42f2d ffffffff86acf380 000000000000002a
> Call Trace:
>  [<     inline     >] __dump_stack lib/dump_stack.c:15
>  [<ffffffff82be2c8d>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50
>  [<ffffffff81355139>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482
>  [<ffffffff81355249>] warn_slowpath_fmt+0xa9/0xd0 kernel/panic.c:494
>  [<ffffffff82c4a78b>] __list_add+0x1db/0x250 lib/list_debug.c:39
>  [<     inline     >] list_move_tail include/linux/list.h:77
>  [<ffffffff85240fdc>] snd_timer_start1+0x6c/0x2c0 sound/core/timer.c:432
>  [<ffffffff85241a7b>] snd_timer_start+0x20b/0x2b0 sound/core/timer.c:499
>  [<     inline     >] snd_timer_user_start sound/core/timer.c:1799
>  [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1883
>  [<ffffffff85245fb7>] snd_timer_user_ioctl+0x767/0x25f0 sound/core/timer.c:1904
>  [<     inline     >] vfs_ioctl fs/ioctl.c:43
>  [<ffffffff817fa9ec>] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
>  [<     inline     >] SYSC_ioctl fs/ioctl.c:689
>  [<ffffffff817fb89f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
>  [<ffffffff8665ebb6>] entry_SYSCALL_64_fastpath+0x16/0x7a
> arch/x86/entry/entry_64.S:185
> ---[ end trace 77da812dd399e78b ]---
> 
> On commit 34229b277480f46c1e9a19f027f30b074512e68b + recent fixes from Takashi.

Thanks for the report.  This is indeed an old bug, but it appears now
more easily due to the recent fix to avoid double-stop.  Below is the
fix patch.  topic/core-fixes branch was updated with this, too.


Takashi

-- 8< --
From: Takashi Iwai <tiwai@suse.de>
Subject: [PATCH] ALSA: timer: Fix leftover link at closing

In ALSA timer core, the active timer instance is managed in
active_list linked list.  Each element is added / removed dynamically
at timer start, stop and in timer interrupt.  The problem is that
snd_timer_interrupt() has a thinko and leaves the element in
active_list when it's the last opened element.  This eventually leads
to list corruption or use-after-free error.

This hasn't been revealed because we used to delete the list forcibly
in snd_timer_stop() in the past.  However, the recent fix avoids the
double-stop behavior (in commit [f784beb75ce8: ALSA: timer: Fix link
corruption due to double start or stop]), and this leak hits reality.

This patch fixes the link management in snd_timer_interrupt().  Now it
simply unlinks no matter which stream is.

BugLink: http://lkml.kernel.org/r/CACT4Y+Yy2aukHP-EDp8-ziNqNNmb-NTf=jDWXMP7jB8HDa2vng@mail.gmail.com
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/core/timer.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/core/timer.c b/sound/core/timer.c
index b419e612f987..9b513a05765a 100644
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -744,8 +744,8 @@ void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
 			ti->cticks = ti->ticks;
 		} else {
 			ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
-			if (--timer->running)
-				list_del_init(&ti->active_list);
+			--timer->running;
+			list_del_init(&ti->active_list);
 		}
 		if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) ||
 		    (ti->flags & SNDRV_TIMER_IFLG_FAST))
-- 
2.7.0

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#1326983

FromDmitry Vyukov <dvyukov@google.com>
Date2016-02-04 17:40 +0100
Message-ID<qYv6O-4s9-11@gated-at.bofh.it>
In reply to#1326964
On Thu, Feb 4, 2016 at 5:24 PM, Takashi Iwai <tiwai@suse.de> wrote:
> On Wed, 03 Feb 2016 17:24:56 +0100,
> Dmitry Vyukov wrote:
>>
>> Hello,
>>
>> The following program triggers use-after-free in snd_timer_start1:
>>
>> // autogenerated by syzkaller (http://github.com/google/syzkaller)
>> #include <pthread.h>
>> #include <stdint.h>
>> #include <string.h>
>> #include <sys/syscall.h>
>> #include <unistd.h>
>>
>> int main()
>> {
>>   syscall(SYS_mmap, 0x20000000ul, 0x664000ul, 0x3ul, 0x32ul,
>>           0xfffffffffffffffful, 0x0ul);
>>   int fd = syscall(SYS_open, "/dev/snd/timer", 0x40000ul, 0, 0, 0);
>>   *(uint32_t*)0x20653000 = (uint32_t)0x1;
>>   *(uint32_t*)0x20653004 = (uint32_t)0xfffffffffffffffe;
>>   *(uint32_t*)0x20653008 = (uint32_t)0x8;
>>   *(uint32_t*)0x2065300c = (uint32_t)0x0;
>>   *(uint32_t*)0x20653010 = (uint32_t)0x0;
>>   *(uint8_t*)0x20653014 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653015 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653016 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653017 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653018 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653019 = (uint8_t)0x0;
>>   *(uint8_t*)0x2065301a = (uint8_t)0x0;
>>   *(uint8_t*)0x2065301b = (uint8_t)0x0;
>>   *(uint8_t*)0x2065301c = (uint8_t)0x0;
>>   *(uint8_t*)0x2065301d = (uint8_t)0x0;
>>   *(uint8_t*)0x2065301e = (uint8_t)0x0;
>>   *(uint8_t*)0x2065301f = (uint8_t)0x0;
>>   *(uint8_t*)0x20653020 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653021 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653022 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653023 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653024 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653025 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653026 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653027 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653028 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653029 = (uint8_t)0x0;
>>   *(uint8_t*)0x2065302a = (uint8_t)0x0;
>>   *(uint8_t*)0x2065302b = (uint8_t)0x0;
>>   *(uint8_t*)0x2065302c = (uint8_t)0x0;
>>   *(uint8_t*)0x2065302d = (uint8_t)0x0;
>>   *(uint8_t*)0x2065302e = (uint8_t)0x0;
>>   *(uint8_t*)0x2065302f = (uint8_t)0x0;
>>   *(uint8_t*)0x20653030 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653031 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653032 = (uint8_t)0x0;
>>   *(uint8_t*)0x20653033 = (uint8_t)0x0;
>>   syscall(SYS_ioctl, fd, 0x40345410ul, 0x20653000ul, 0, 0, 0);
>>   syscall(SYS_ioctl, fd, 0x54a0ul, 0, 0, 0, 0);
>>   return 0;
>> }
>>
>> ==================================================================
>> BUG: KASAN: use-after-free in __list_add+0x233/0x22016/02/03 13:44:32
>> executing program 0:
>> Read of size 8 by task syz-executor/27661
>>
>> INFO: Allocated in snd_timer_instance_new+0x52/0x3a0 age=7 cpu=0 pid=27660
>> [<     inline     >] slab_alloc_node mm/slub.c:2562
>> [<     inline     >] slab_alloc mm/slub.c:2604
>> [<      none      >] kmem_cache_alloc_trace+0x25c/0x300 mm/slub.c:2621
>> [<     inline     >] kmalloc include/linux/slab.h:463
>> [<     inline     >] kzalloc include/linux/slab.h:607
>> [<      none      >] snd_timer_instance_new+0x52/0x3a0 sound/core/timer.c:106
>> [<      none      >] snd_timer_open+0x522/0xd20 sound/core/timer.c:289
>> [<     inline     >] snd_timer_user_tselect sound/core/timer.c:1598
>> [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1874
>> [<      none      >] snd_timer_user_ioctl+0x8db/0x25f0 sound/core/timer.c:1904
>> [<     inline     >] vfs_ioctl fs/ioctl.c:43
>> [<      none      >] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
>> [<     inline     >] SYSC_ioctl fs/ioctl.c:689
>> [<      none      >] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
>> [<      none      >] entry_SYSCALL_64_fastpath+0x16/0x7a
>> arch/x86/entry/entry_64.S:185
>>
>> INFO: Freed in snd_timer_close+0x3ee/0x750 age=9 cpu=3 pid=27661
>> [<     inline     >] slab_free mm/slub.c:2835
>> [<      none      >] kfree+0x2ac/0x2c0 mm/slub.c:3664
>> [<      none      >] snd_timer_close+0x3ee/0x750 sound/core/timer.c:375
>> [<     inline     >] snd_timer_user_tselect sound/core/timer.c:1588
>> [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1874
>> [<      none      >] snd_timer_user_ioctl+0x7b6/0x25f0 sound/core/timer.c:1904
>> [<     inline     >] vfs_ioctl fs/ioctl.c:43
>> [<      none      >] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
>> [<     inline     >] SYSC_ioctl fs/ioctl.c:689
>> [<      none      >] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
>> [<      none      >] entry_SYSCALL_64_fastpath+0x16/0x7a
>> arch/x86/entry/entry_64.S:185
>>
>> Call Trace:
>>  [<     inline     >] kasan_report mm/kasan/report.c:274
>>  [<ffffffff8176640e>] __asan_report_load8_noabort+0x3e/0x40
>> mm/kasan/report.c:295
>>  [<ffffffff82c4a7e3>] __list_add+0x233/0x250 lib/list_debug.c:39
>>  [<     inline     >] list_move_tail include/linux/list.h:77
>>  [<ffffffff85240fdc>] snd_timer_start1+0x6c/0x2c0 sound/core/timer.c:432
>>  [<ffffffff85241a7b>] snd_timer_start+0x20b/0x2b0 sound/core/timer.c:499
>>  [<     inline     >] snd_timer_user_start sound/core/timer.c:1799
>>  [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1883
>>  [<ffffffff85245fb7>] snd_timer_user_ioctl+0x767/0x25f0 sound/core/timer.c:1904
>>  [<     inline     >] vfs_ioctl fs/ioctl.c:43
>>  [<ffffffff817fa9ec>] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
>>  [<     inline     >] SYSC_ioctl fs/ioctl.c:689
>>  [<ffffffff817fb89f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
>>  [<ffffffff8665ebb6>] entry_SYSCALL_64_fastpath+0x16/0x7a
>> arch/x86/entry/entry_64.S:185
>> ==================================================================
>>
>>
>> Sometimes it manifests as:
>>
>> ------------[ cut here ]------------
>> WARNING: CPU: 1 PID: 6548 at lib/list_debug.c:42 __list_add+0x1db/0x250()
>> list_add corruption. prev->next should be next (ffff8800697c10e8), but
>> was ffff880030441fd0. (prev=ffff880030441fd0).
>> Modules linked in:
>> CPU: 1 PID: 6548 Comm: a.out Not tainted 4.5.0-rc2+ #309
>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
>>  00000000ffffffff ffff88002fa17918 ffffffff82be2c8d ffff88002fa17988
>>  ffff88002fd62f80 ffffffff86acf380 ffff88002fa17958 ffffffff81355139
>>  ffffffff82c4a78b ffffed0005f42f2d ffffffff86acf380 000000000000002a
>> Call Trace:
>>  [<     inline     >] __dump_stack lib/dump_stack.c:15
>>  [<ffffffff82be2c8d>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50
>>  [<ffffffff81355139>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482
>>  [<ffffffff81355249>] warn_slowpath_fmt+0xa9/0xd0 kernel/panic.c:494
>>  [<ffffffff82c4a78b>] __list_add+0x1db/0x250 lib/list_debug.c:39
>>  [<     inline     >] list_move_tail include/linux/list.h:77
>>  [<ffffffff85240fdc>] snd_timer_start1+0x6c/0x2c0 sound/core/timer.c:432
>>  [<ffffffff85241a7b>] snd_timer_start+0x20b/0x2b0 sound/core/timer.c:499
>>  [<     inline     >] snd_timer_user_start sound/core/timer.c:1799
>>  [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1883
>>  [<ffffffff85245fb7>] snd_timer_user_ioctl+0x767/0x25f0 sound/core/timer.c:1904
>>  [<     inline     >] vfs_ioctl fs/ioctl.c:43
>>  [<ffffffff817fa9ec>] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
>>  [<     inline     >] SYSC_ioctl fs/ioctl.c:689
>>  [<ffffffff817fb89f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
>>  [<ffffffff8665ebb6>] entry_SYSCALL_64_fastpath+0x16/0x7a
>> arch/x86/entry/entry_64.S:185
>> ---[ end trace 77da812dd399e78b ]---
>>
>> On commit 34229b277480f46c1e9a19f027f30b074512e68b + recent fixes from Takashi.
>
> Thanks for the report.  This is indeed an old bug, but it appears now
> more easily due to the recent fix to avoid double-stop.  Below is the
> fix patch.  topic/core-fixes branch was updated with this, too.


Fixes the crash for me.
I think this was the last one in sound that happened periodically
during fuzzing. Let's see what the fuzzer will say now :)
Thanks for quick fixes!


> -- 8< --
> From: Takashi Iwai <tiwai@suse.de>
> Subject: [PATCH] ALSA: timer: Fix leftover link at closing
>
> In ALSA timer core, the active timer instance is managed in
> active_list linked list.  Each element is added / removed dynamically
> at timer start, stop and in timer interrupt.  The problem is that
> snd_timer_interrupt() has a thinko and leaves the element in
> active_list when it's the last opened element.  This eventually leads
> to list corruption or use-after-free error.
>
> This hasn't been revealed because we used to delete the list forcibly
> in snd_timer_stop() in the past.  However, the recent fix avoids the
> double-stop behavior (in commit [f784beb75ce8: ALSA: timer: Fix link
> corruption due to double start or stop]), and this leak hits reality.
>
> This patch fixes the link management in snd_timer_interrupt().  Now it
> simply unlinks no matter which stream is.
>
> BugLink: http://lkml.kernel.org/r/CACT4Y+Yy2aukHP-EDp8-ziNqNNmb-NTf=jDWXMP7jB8HDa2vng@mail.gmail.com
> Reported-by: Dmitry Vyukov <dvyukov@google.com>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> ---
>  sound/core/timer.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/sound/core/timer.c b/sound/core/timer.c
> index b419e612f987..9b513a05765a 100644
> --- a/sound/core/timer.c
> +++ b/sound/core/timer.c
> @@ -744,8 +744,8 @@ void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
>                         ti->cticks = ti->ticks;
>                 } else {
>                         ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
> -                       if (--timer->running)
> -                               list_del_init(&ti->active_list);
> +                       --timer->running;
> +                       list_del_init(&ti->active_list);
>                 }
>                 if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) ||
>                     (ti->flags & SNDRV_TIMER_IFLG_FAST))
> --
> 2.7.0
>
>

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#1326988

FromTakashi Iwai <tiwai@suse.de>
Date2016-02-04 17:40 +0100
Message-ID<qYv6P-4s9-27@gated-at.bofh.it>
In reply to#1326983
On Thu, 04 Feb 2016 17:32:31 +0100,
Dmitry Vyukov wrote:
> 
> On Thu, Feb 4, 2016 at 5:24 PM, Takashi Iwai <tiwai@suse.de> wrote:
> > On Wed, 03 Feb 2016 17:24:56 +0100,
> > Dmitry Vyukov wrote:
> >>
> >> Hello,
> >>
> >> The following program triggers use-after-free in snd_timer_start1:
> >>
> >> // autogenerated by syzkaller (http://github.com/google/syzkaller)
> >> #include <pthread.h>
> >> #include <stdint.h>
> >> #include <string.h>
> >> #include <sys/syscall.h>
> >> #include <unistd.h>
> >>
> >> int main()
> >> {
> >>   syscall(SYS_mmap, 0x20000000ul, 0x664000ul, 0x3ul, 0x32ul,
> >>           0xfffffffffffffffful, 0x0ul);
> >>   int fd = syscall(SYS_open, "/dev/snd/timer", 0x40000ul, 0, 0, 0);
> >>   *(uint32_t*)0x20653000 = (uint32_t)0x1;
> >>   *(uint32_t*)0x20653004 = (uint32_t)0xfffffffffffffffe;
> >>   *(uint32_t*)0x20653008 = (uint32_t)0x8;
> >>   *(uint32_t*)0x2065300c = (uint32_t)0x0;
> >>   *(uint32_t*)0x20653010 = (uint32_t)0x0;
> >>   *(uint8_t*)0x20653014 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653015 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653016 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653017 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653018 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653019 = (uint8_t)0x0;
> >>   *(uint8_t*)0x2065301a = (uint8_t)0x0;
> >>   *(uint8_t*)0x2065301b = (uint8_t)0x0;
> >>   *(uint8_t*)0x2065301c = (uint8_t)0x0;
> >>   *(uint8_t*)0x2065301d = (uint8_t)0x0;
> >>   *(uint8_t*)0x2065301e = (uint8_t)0x0;
> >>   *(uint8_t*)0x2065301f = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653020 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653021 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653022 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653023 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653024 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653025 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653026 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653027 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653028 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653029 = (uint8_t)0x0;
> >>   *(uint8_t*)0x2065302a = (uint8_t)0x0;
> >>   *(uint8_t*)0x2065302b = (uint8_t)0x0;
> >>   *(uint8_t*)0x2065302c = (uint8_t)0x0;
> >>   *(uint8_t*)0x2065302d = (uint8_t)0x0;
> >>   *(uint8_t*)0x2065302e = (uint8_t)0x0;
> >>   *(uint8_t*)0x2065302f = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653030 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653031 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653032 = (uint8_t)0x0;
> >>   *(uint8_t*)0x20653033 = (uint8_t)0x0;
> >>   syscall(SYS_ioctl, fd, 0x40345410ul, 0x20653000ul, 0, 0, 0);
> >>   syscall(SYS_ioctl, fd, 0x54a0ul, 0, 0, 0, 0);
> >>   return 0;
> >> }
> >>
> >> ==================================================================
> >> BUG: KASAN: use-after-free in __list_add+0x233/0x22016/02/03 13:44:32
> >> executing program 0:
> >> Read of size 8 by task syz-executor/27661
> >>
> >> INFO: Allocated in snd_timer_instance_new+0x52/0x3a0 age=7 cpu=0 pid=27660
> >> [<     inline     >] slab_alloc_node mm/slub.c:2562
> >> [<     inline     >] slab_alloc mm/slub.c:2604
> >> [<      none      >] kmem_cache_alloc_trace+0x25c/0x300 mm/slub.c:2621
> >> [<     inline     >] kmalloc include/linux/slab.h:463
> >> [<     inline     >] kzalloc include/linux/slab.h:607
> >> [<      none      >] snd_timer_instance_new+0x52/0x3a0 sound/core/timer.c:106
> >> [<      none      >] snd_timer_open+0x522/0xd20 sound/core/timer.c:289
> >> [<     inline     >] snd_timer_user_tselect sound/core/timer.c:1598
> >> [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1874
> >> [<      none      >] snd_timer_user_ioctl+0x8db/0x25f0 sound/core/timer.c:1904
> >> [<     inline     >] vfs_ioctl fs/ioctl.c:43
> >> [<      none      >] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
> >> [<     inline     >] SYSC_ioctl fs/ioctl.c:689
> >> [<      none      >] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
> >> [<      none      >] entry_SYSCALL_64_fastpath+0x16/0x7a
> >> arch/x86/entry/entry_64.S:185
> >>
> >> INFO: Freed in snd_timer_close+0x3ee/0x750 age=9 cpu=3 pid=27661
> >> [<     inline     >] slab_free mm/slub.c:2835
> >> [<      none      >] kfree+0x2ac/0x2c0 mm/slub.c:3664
> >> [<      none      >] snd_timer_close+0x3ee/0x750 sound/core/timer.c:375
> >> [<     inline     >] snd_timer_user_tselect sound/core/timer.c:1588
> >> [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1874
> >> [<      none      >] snd_timer_user_ioctl+0x7b6/0x25f0 sound/core/timer.c:1904
> >> [<     inline     >] vfs_ioctl fs/ioctl.c:43
> >> [<      none      >] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
> >> [<     inline     >] SYSC_ioctl fs/ioctl.c:689
> >> [<      none      >] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
> >> [<      none      >] entry_SYSCALL_64_fastpath+0x16/0x7a
> >> arch/x86/entry/entry_64.S:185
> >>
> >> Call Trace:
> >>  [<     inline     >] kasan_report mm/kasan/report.c:274
> >>  [<ffffffff8176640e>] __asan_report_load8_noabort+0x3e/0x40
> >> mm/kasan/report.c:295
> >>  [<ffffffff82c4a7e3>] __list_add+0x233/0x250 lib/list_debug.c:39
> >>  [<     inline     >] list_move_tail include/linux/list.h:77
> >>  [<ffffffff85240fdc>] snd_timer_start1+0x6c/0x2c0 sound/core/timer.c:432
> >>  [<ffffffff85241a7b>] snd_timer_start+0x20b/0x2b0 sound/core/timer.c:499
> >>  [<     inline     >] snd_timer_user_start sound/core/timer.c:1799
> >>  [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1883
> >>  [<ffffffff85245fb7>] snd_timer_user_ioctl+0x767/0x25f0 sound/core/timer.c:1904
> >>  [<     inline     >] vfs_ioctl fs/ioctl.c:43
> >>  [<ffffffff817fa9ec>] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
> >>  [<     inline     >] SYSC_ioctl fs/ioctl.c:689
> >>  [<ffffffff817fb89f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
> >>  [<ffffffff8665ebb6>] entry_SYSCALL_64_fastpath+0x16/0x7a
> >> arch/x86/entry/entry_64.S:185
> >> ==================================================================
> >>
> >>
> >> Sometimes it manifests as:
> >>
> >> ------------[ cut here ]------------
> >> WARNING: CPU: 1 PID: 6548 at lib/list_debug.c:42 __list_add+0x1db/0x250()
> >> list_add corruption. prev->next should be next (ffff8800697c10e8), but
> >> was ffff880030441fd0. (prev=ffff880030441fd0).
> >> Modules linked in:
> >> CPU: 1 PID: 6548 Comm: a.out Not tainted 4.5.0-rc2+ #309
> >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> >>  00000000ffffffff ffff88002fa17918 ffffffff82be2c8d ffff88002fa17988
> >>  ffff88002fd62f80 ffffffff86acf380 ffff88002fa17958 ffffffff81355139
> >>  ffffffff82c4a78b ffffed0005f42f2d ffffffff86acf380 000000000000002a
> >> Call Trace:
> >>  [<     inline     >] __dump_stack lib/dump_stack.c:15
> >>  [<ffffffff82be2c8d>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50
> >>  [<ffffffff81355139>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482
> >>  [<ffffffff81355249>] warn_slowpath_fmt+0xa9/0xd0 kernel/panic.c:494
> >>  [<ffffffff82c4a78b>] __list_add+0x1db/0x250 lib/list_debug.c:39
> >>  [<     inline     >] list_move_tail include/linux/list.h:77
> >>  [<ffffffff85240fdc>] snd_timer_start1+0x6c/0x2c0 sound/core/timer.c:432
> >>  [<ffffffff85241a7b>] snd_timer_start+0x20b/0x2b0 sound/core/timer.c:499
> >>  [<     inline     >] snd_timer_user_start sound/core/timer.c:1799
> >>  [<     inline     >] __snd_timer_user_ioctl sound/core/timer.c:1883
> >>  [<ffffffff85245fb7>] snd_timer_user_ioctl+0x767/0x25f0 sound/core/timer.c:1904
> >>  [<     inline     >] vfs_ioctl fs/ioctl.c:43
> >>  [<ffffffff817fa9ec>] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
> >>  [<     inline     >] SYSC_ioctl fs/ioctl.c:689
> >>  [<ffffffff817fb89f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
> >>  [<ffffffff8665ebb6>] entry_SYSCALL_64_fastpath+0x16/0x7a
> >> arch/x86/entry/entry_64.S:185
> >> ---[ end trace 77da812dd399e78b ]---
> >>
> >> On commit 34229b277480f46c1e9a19f027f30b074512e68b + recent fixes from Takashi.
> >
> > Thanks for the report.  This is indeed an old bug, but it appears now
> > more easily due to the recent fix to avoid double-stop.  Below is the
> > fix patch.  topic/core-fixes branch was updated with this, too.
> 
> 
> Fixes the crash for me.
> I think this was the last one in sound that happened periodically
> during fuzzing. Let's see what the fuzzer will say now :)
> Thanks for quick fixes!

Great, thanks for your patient reports and testing!


Takashi

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