From 66efdc71d95887b652a742a5dae51fa834d71465 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 8 Mar 2013 18:11:17 +0100 Subject: [PATCH] ALSA: seq: Fix missing error handling in snd_seq_timer_open() 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: [] 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:[] [] 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: [] ? trace_hardirqs_on+0xd/0x10 [] snd_seq_queue_timer_open+0x29/0x70 [] snd_seq_ioctl_set_queue_timer+0xda/0x120 [] snd_seq_do_ioctl+0x9b/0xd0 [] snd_seq_ioctl+0x10/0x20 [] do_vfs_ioctl+0x522/0x570 [] ? file_has_perm+0x83/0xa0 [] ? trace_hardirqs_on+0xd/0x10 [] sys_ioctl+0x5d/0xa0 [] ? trace_hardirqs_on_thunk+0x3a/0x3f [] system_call_fastpath+0x16/0x1b Reported-and-tested-by: Tommi Rantala Cc: Signed-off-by: Takashi Iwai --- sound/core/seq/seq_timer.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/sound/core/seq/seq_timer.c b/sound/core/seq/seq_timer.c index 160b1bd0cd62..24d44b2f61ac 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; -- 2.39.5