Patchwork [3.5.y.z,extended,stable] Patch "ALSA: seq: Fix missing error handling in snd_seq_timer_open()" has been added to staging queue

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Submitter Luis Henriques
Date March 19, 2013, 12:22 p.m.
Message ID <1363695746-7614-1-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/229023/
State New
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Comments

Luis Henriques - March 19, 2013, 12:22 p.m.
This is a note to let you know that I have just added a patch titled

    ALSA: seq: Fix missing error handling in snd_seq_timer_open()

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

From 855cdc65a134171bee4e7c874bb01262449777ac Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Fri, 8 Mar 2013 18:11:17 +0100
Subject: [PATCH] ALSA: seq: Fix missing error handling in snd_seq_timer_open()

commit 66efdc71d95887b652a742a5dae51fa834d71465 upstream.

snd_seq_timer_open() didn't catch the whole error path but let through
if the timer id is a slave.  This may lead to Oops by accessing the
uninitialized pointer.

 BUG: unable to handle kernel NULL pointer dereference at 00000000000002ae
 IP: [<ffffffff819b3477>] snd_seq_timer_open+0xe7/0x130
 PGD 785cd067 PUD 76964067 PMD 0
 Oops: 0002 [#4] SMP
 CPU 0
 Pid: 4288, comm: trinity-child7 Tainted: G      D W 3.9.0-rc1+ #100 Bochs Bochs
 RIP: 0010:[<ffffffff819b3477>]  [<ffffffff819b3477>] snd_seq_timer_open+0xe7/0x130
 RSP: 0018:ffff88006ece7d38  EFLAGS: 00010246
 RAX: 0000000000000286 RBX: ffff88007851b400 RCX: 0000000000000000
 RDX: 000000000000ffff RSI: ffff88006ece7d58 RDI: ffff88006ece7d38
 RBP: ffff88006ece7d98 R08: 000000000000000a R09: 000000000000fffe
 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
 R13: ffff8800792c5400 R14: 0000000000e8f000 R15: 0000000000000007
 FS:  00007f7aaa650700(0000) GS:ffff88007f800000(0000) GS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00000000000002ae CR3: 000000006efec000 CR4: 00000000000006f0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
 Process trinity-child7 (pid: 4288, threadinfo ffff88006ece6000, task ffff880076a8a290)
 Stack:
  0000000000000286 ffffffff828f2be0 ffff88006ece7d58 ffffffff810f354d
  65636e6575716573 2065756575712072 ffff8800792c0030 0000000000000000
  ffff88006ece7d98 ffff8800792c5400 ffff88007851b400 ffff8800792c5520
 Call Trace:
  [<ffffffff810f354d>] ? trace_hardirqs_on+0xd/0x10
  [<ffffffff819b17e9>] snd_seq_queue_timer_open+0x29/0x70
  [<ffffffff819ae01a>] snd_seq_ioctl_set_queue_timer+0xda/0x120
  [<ffffffff819acb9b>] snd_seq_do_ioctl+0x9b/0xd0
  [<ffffffff819acbe0>] snd_seq_ioctl+0x10/0x20
  [<ffffffff811b9542>] do_vfs_ioctl+0x522/0x570
  [<ffffffff8130a4b3>] ? file_has_perm+0x83/0xa0
  [<ffffffff810f354d>] ? trace_hardirqs_on+0xd/0x10
  [<ffffffff811b95ed>] sys_ioctl+0x5d/0xa0
  [<ffffffff813663fe>] ? trace_hardirqs_on_thunk+0x3a/0x3f
  [<ffffffff81faed69>] system_call_fastpath+0x16/0x1b

Reported-and-tested-by: Tommi Rantala <tt.rantala@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Luis Henriques <luis.henriques@canonical.com>
---
 sound/core/seq/seq_timer.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--
1.8.1.2

Patch

diff --git a/sound/core/seq/seq_timer.c b/sound/core/seq/seq_timer.c
index 160b1bd..24d44b2 100644
--- a/sound/core/seq/seq_timer.c
+++ b/sound/core/seq/seq_timer.c
@@ -290,10 +290,10 @@  int snd_seq_timer_open(struct snd_seq_queue *q)
 			tid.device = SNDRV_TIMER_GLOBAL_SYSTEM;
 			err = snd_timer_open(&t, str, &tid, q->queue);
 		}
-		if (err < 0) {
-			snd_printk(KERN_ERR "seq fatal error: cannot create timer (%i)\n", err);
-			return err;
-		}
+	}
+	if (err < 0) {
+		snd_printk(KERN_ERR "seq fatal error: cannot create timer (%i)\n", err);
+		return err;
 	}
 	t->callback = snd_seq_timer_interrupt;
 	t->callback_data = q;