From 6b760bb2c63a9e322c0e4a0b5daf335ad93d5a33 Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Mon, 29 Aug 2016 00:33:50 +0200 Subject: ALSA: timer: fix division by zero after SNDRV_TIMER_IOCTL_CONTINUE I got this: divide error: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 1327 Comm: a.out Not tainted 4.8.0-rc2+ #189 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014 task: ffff8801120a9580 task.stack: ffff8801120b0000 RIP: 0010:[] [] snd_hrtimer_callback+0x1da/0x3f0 RSP: 0018:ffff88011aa87da8 EFLAGS: 00010006 RAX: 0000000000004f76 RBX: ffff880112655e88 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff880112655ea0 RDI: 0000000000000001 RBP: ffff88011aa87e00 R08: ffff88013fff905c R09: ffff88013fff9048 R10: ffff88013fff9050 R11: 00000001050a7b8c R12: ffff880114778a00 R13: ffff880114778ab4 R14: ffff880114778b30 R15: 0000000000000000 FS: 00007f071647c700(0000) GS:ffff88011aa80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000603001 CR3: 0000000112021000 CR4: 00000000000006e0 Stack: 0000000000000000 ffff880114778ab8 ffff880112655ea0 0000000000004f76 ffff880112655ec8 ffff880112655e80 ffff880112655e88 ffff88011aa98fc0 00000000b97ccf2b dffffc0000000000 ffff88011aa98fc0 ffff88011aa87ef0 Call Trace: [] __hrtimer_run_queues+0x347/0xa00 [] ? snd_hrtimer_close+0x130/0x130 [] ? retrigger_next_event+0x1b0/0x1b0 [] ? hrtimer_interrupt+0x136/0x4b0 [] hrtimer_interrupt+0x1b0/0x4b0 [] local_apic_timer_interrupt+0x6e/0xf0 [] ? kvm_guest_apic_eoi_write+0x13/0xc0 [] smp_apic_timer_interrupt+0x76/0xa0 [] apic_timer_interrupt+0x8c/0xa0 [] ? _raw_spin_unlock_irqrestore+0x2c/0x60 [] snd_timer_start1+0xdd/0x670 [] snd_timer_continue+0x45/0x80 [] snd_timer_user_ioctl+0x1030/0x2830 [] ? __follow_pte.isra.49+0x430/0x430 [] ? snd_timer_pause+0x80/0x80 [] ? do_wp_page+0x3aa/0x1c90 [] ? handle_mm_fault+0xbc8/0x27f0 [] ? __pmd_alloc+0x370/0x370 [] ? snd_timer_pause+0x80/0x80 [] do_vfs_ioctl+0x193/0x1050 [] ? ioctl_preallocate+0x200/0x200 [] ? syscall_trace_enter+0x3cf/0xdb0 [] ? __context_tracking_exit.part.4+0x9a/0x1e0 [] ? exit_to_usermode_loop+0x190/0x190 [] ? check_preemption_disabled+0x37/0x1e0 [] ? security_file_ioctl+0x89/0xb0 [] SyS_ioctl+0x8f/0xc0 [] ? do_vfs_ioctl+0x1050/0x1050 [] do_syscall_64+0x1c4/0x4e0 [] entry_SYSCALL64_slow_path+0x25/0x25 Code: e8 fc 42 7b fe 8b 0d 06 8a 50 03 49 0f af cf 48 85 c9 0f 88 7c 01 00 00 48 89 4d a8 e8 e0 42 7b fe 48 8b 45 c0 48 8b 4d a8 48 99 <48> f7 f9 49 01 c7 e8 cb 42 7b fe 48 8b 55 d0 48 b8 00 00 00 00 RIP [] snd_hrtimer_callback+0x1da/0x3f0 RSP ---[ end trace 6aa380f756a21074 ]--- The problem happens when you call ioctl(SNDRV_TIMER_IOCTL_CONTINUE) on a completely new/unused timer -- it will have ->sticks == 0, which causes a divide by 0 in snd_hrtimer_callback(). Signed-off-by: Vegard Nossum Cc: Signed-off-by: Takashi Iwai --- sound/core/timer.c | 1 + 1 file changed, 1 insertion(+) (limited to 'sound/core') diff --git a/sound/core/timer.c b/sound/core/timer.c index 9a6157ea6881..00618703c58f 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -813,6 +813,7 @@ int snd_timer_new(struct snd_card *card, char *id, struct snd_timer_id *tid, timer->tmr_subdevice = tid->subdevice; if (id) strlcpy(timer->id, id, sizeof(timer->id)); + timer->sticks = 1; INIT_LIST_HEAD(&timer->device_list); INIT_LIST_HEAD(&timer->open_list_head); INIT_LIST_HEAD(&timer->active_list_head); -- cgit v1.2.3 From 8ddc05638ee42b18ba4fe99b5fb647fa3ad20456 Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Mon, 29 Aug 2016 00:33:51 +0200 Subject: ALSA: timer: fix NULL pointer dereference on memory allocation failure I hit this with syzkaller: kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 1327 Comm: a.out Not tainted 4.8.0-rc2+ #190 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014 task: ffff88011278d600 task.stack: ffff8801120c0000 RIP: 0010:[] [] snd_hrtimer_start+0x77/0x100 RSP: 0018:ffff8801120c7a60 EFLAGS: 00010006 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000007 RDX: 0000000000000009 RSI: 1ffff10023483091 RDI: 0000000000000048 RBP: ffff8801120c7a78 R08: ffff88011a5cf768 R09: ffff88011a5ba790 R10: 0000000000000002 R11: ffffed00234b9ef1 R12: ffff880114843980 R13: ffffffff84213c00 R14: ffff880114843ab0 R15: 0000000000000286 FS: 00007f72958f3700(0000) GS:ffff88011aa00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000603001 CR3: 00000001126ab000 CR4: 00000000000006f0 Stack: ffff880114843980 ffff880111eb2dc0 ffff880114843a34 ffff8801120c7ad0 ffffffff82c81ab1 0000000000000000 ffffffff842138e0 0000000100000000 ffff880111eb2dd0 ffff880111eb2dc0 0000000000000001 ffff880111eb2dc0 Call Trace: [] snd_timer_start1+0x331/0x670 [] snd_timer_start+0x5d/0xa0 [] snd_timer_user_ioctl+0x88e/0x2830 [] ? __follow_pte.isra.49+0x430/0x430 [] ? snd_timer_pause+0x80/0x80 [] ? do_wp_page+0x3aa/0x1c90 [] ? put_prev_entity+0x108f/0x21a0 [] ? snd_timer_pause+0x80/0x80 [] do_vfs_ioctl+0x193/0x1050 [] ? cpuacct_account_field+0x12f/0x1a0 [] ? ioctl_preallocate+0x200/0x200 [] ? syscall_trace_enter+0x3cf/0xdb0 [] ? __context_tracking_exit.part.4+0x9a/0x1e0 [] ? exit_to_usermode_loop+0x190/0x190 [] ? check_preemption_disabled+0x37/0x1e0 [] ? security_file_ioctl+0x89/0xb0 [] SyS_ioctl+0x8f/0xc0 [] ? do_vfs_ioctl+0x1050/0x1050 [] do_syscall_64+0x1c4/0x4e0 [] entry_SYSCALL64_slow_path+0x25/0x25 Code: c7 c7 c4 b9 c8 82 48 89 d9 4c 89 ee e8 63 88 7f fe e8 7e 46 7b fe 48 8d 7b 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 04 84 c0 7e 65 80 7b 48 00 74 0e e8 52 46 RIP [] snd_hrtimer_start+0x77/0x100 RSP ---[ end trace 5955b08db7f2b029 ]--- This can happen if snd_hrtimer_open() fails to allocate memory and returns an error, which is currently not checked by snd_timer_open(): ioctl(SNDRV_TIMER_IOCTL_SELECT) - snd_timer_user_tselect() - snd_timer_close() - snd_hrtimer_close() - (struct snd_timer *) t->private_data = NULL - snd_timer_open() - snd_hrtimer_open() - kzalloc() fails; t->private_data is still NULL ioctl(SNDRV_TIMER_IOCTL_START) - snd_timer_user_start() - snd_timer_start() - snd_timer_start1() - snd_hrtimer_start() - t->private_data == NULL // boom Signed-off-by: Vegard Nossum Cc: Signed-off-by: Takashi Iwai --- sound/core/timer.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'sound/core') diff --git a/sound/core/timer.c b/sound/core/timer.c index 00618703c58f..2d6e3e76ddf5 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -294,8 +294,21 @@ int snd_timer_open(struct snd_timer_instance **ti, get_device(&timer->card->card_dev); timeri->slave_class = tid->dev_sclass; timeri->slave_id = slave_id; - if (list_empty(&timer->open_list_head) && timer->hw.open) - timer->hw.open(timer); + + if (list_empty(&timer->open_list_head) && timer->hw.open) { + int err = timer->hw.open(timer); + if (err) { + kfree(timeri->owner); + kfree(timeri); + + if (timer->card) + put_device(&timer->card->card_dev); + module_put(timer->module); + mutex_unlock(®ister_mutex); + return err; + } + } + list_add_tail(&timeri->open_list, &timer->open_list_head); snd_timer_check_master(timeri); mutex_unlock(®ister_mutex); -- cgit v1.2.3 From 11749e086b2766cccf6217a527ef5c5604ba069c Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Sun, 28 Aug 2016 10:13:07 +0200 Subject: ALSA: timer: fix NULL pointer dereference in read()/ioctl() race I got this with syzkaller: ================================================================== BUG: KASAN: null-ptr-deref on address 0000000000000020 Read of size 32 by task syz-executor/22519 CPU: 1 PID: 22519 Comm: syz-executor Not tainted 4.8.0-rc2+ #169 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2 014 0000000000000001 ffff880111a17a00 ffffffff81f9f141 ffff880111a17a90 ffff880111a17c50 ffff880114584a58 ffff880114584a10 ffff880111a17a80 ffffffff8161fe3f ffff880100000000 ffff880118d74a48 ffff880118d74a68 Call Trace: [] dump_stack+0x83/0xb2 [] kasan_report_error+0x41f/0x4c0 [] kasan_report+0x34/0x40 [] ? snd_timer_user_read+0x554/0x790 [] check_memory_region+0x13e/0x1a0 [] kasan_check_read+0x11/0x20 [] snd_timer_user_read+0x554/0x790 [] ? snd_timer_user_info_compat.isra.5+0x2b0/0x2b0 [] ? proc_fault_inject_write+0x1c1/0x250 [] ? next_tgid+0x2a0/0x2a0 [] ? do_group_exit+0x108/0x330 [] ? fsnotify+0x72a/0xca0 [] __vfs_read+0x10e/0x550 [] ? snd_timer_user_info_compat.isra.5+0x2b0/0x2b0 [] ? do_sendfile+0xc50/0xc50 [] ? __fsnotify_update_child_dentry_flags+0x60/0x60 [] ? kcov_ioctl+0x56/0x190 [] ? common_file_perm+0x2e2/0x380 [] ? __fsnotify_parent+0x5e/0x2b0 [] ? security_file_permission+0x86/0x1e0 [] ? rw_verify_area+0xe5/0x2b0 [] vfs_read+0x115/0x330 [] SyS_read+0xd1/0x1a0 [] ? vfs_write+0x4b0/0x4b0 [] ? __this_cpu_preempt_check+0x1c/0x20 [] ? __context_tracking_exit.part.4+0x3a/0x1e0 [] ? vfs_write+0x4b0/0x4b0 [] do_syscall_64+0x1c4/0x4e0 [] ? syscall_return_slowpath+0x16c/0x1d0 [] entry_SYSCALL64_slow_path+0x25/0x25 ================================================================== There are a couple of problems that I can see: - ioctl(SNDRV_TIMER_IOCTL_SELECT), which potentially sets tu->queue/tu->tqueue to NULL on memory allocation failure, so read() would get a NULL pointer dereference like the above splat - the same ioctl() can free tu->queue/to->tqueue which means read() could potentially see (and dereference) the freed pointer We can fix both by taking the ioctl_lock mutex when dereferencing ->queue/->tqueue, since that's always held over all the ioctl() code. Just looking at the code I find it likely that there are more problems here such as tu->qhead pointing outside the buffer if the size is changed concurrently using SNDRV_TIMER_IOCTL_PARAMS. Signed-off-by: Vegard Nossum Cc: Signed-off-by: Takashi Iwai --- sound/core/timer.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'sound/core') diff --git a/sound/core/timer.c b/sound/core/timer.c index 2d6e3e76ddf5..2706061fc1ea 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -1972,6 +1972,7 @@ static ssize_t snd_timer_user_read(struct file *file, char __user *buffer, tu->qused--; spin_unlock_irq(&tu->qlock); + mutex_lock(&tu->ioctl_lock); if (tu->tread) { if (copy_to_user(buffer, &tu->tqueue[qhead], sizeof(struct snd_timer_tread))) @@ -1981,6 +1982,7 @@ static ssize_t snd_timer_user_read(struct file *file, char __user *buffer, sizeof(struct snd_timer_read))) err = -EFAULT; } + mutex_unlock(&tu->ioctl_lock); spin_lock_irq(&tu->qlock); if (err < 0) -- cgit v1.2.3 From 9f8a7658bcafb2a7853f7a2eae8a94e87e6e695b Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Wed, 7 Sep 2016 15:45:31 +0200 Subject: ALSA: timer: Fix zero-division by continue of uninitialized instance When a user timer instance is continued without the explicit start beforehand, the system gets eventually zero-division error like: divide error: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN CPU: 1 PID: 27320 Comm: syz-executor Not tainted 4.8.0-rc3-next-20160825+ #8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff88003c9b2280 task.stack: ffff880027280000 RIP: 0010:[] [< inline >] ktime_divns include/linux/ktime.h:195 RIP: 0010:[] [] snd_hrtimer_callback+0x1bc/0x3c0 sound/core/hrtimer.c:62 Call Trace: [< inline >] __run_hrtimer kernel/time/hrtimer.c:1238 [] __hrtimer_run_queues+0x325/0xe70 kernel/time/hrtimer.c:1302 [] hrtimer_interrupt+0x18b/0x420 kernel/time/hrtimer.c:1336 [] local_apic_timer_interrupt+0x6f/0xe0 arch/x86/kernel/apic/apic.c:933 [] smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:957 [] apic_timer_interrupt+0x8c/0xa0 arch/x86/entry/entry_64.S:487 ..... Although a similar issue was spotted and a fix patch was merged in commit [6b760bb2c63a: ALSA: timer: fix division by zero after SNDRV_TIMER_IOCTL_CONTINUE], it seems covering only a part of iceberg. In this patch, we fix the issue a bit more drastically. Basically the continue of an uninitialized timer is supposed to be a fresh start, so we do it for user timers. For the direct snd_timer_continue() call, there is no way to pass the initial tick value, so we kick out for the uninitialized case. Reported-by: Dmitry Vyukov Cc: Signed-off-by: Takashi Iwai --- sound/core/timer.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'sound/core') diff --git a/sound/core/timer.c b/sound/core/timer.c index 2706061fc1ea..fc144f43faa6 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -35,6 +35,9 @@ #include #include +/* internal flags */ +#define SNDRV_TIMER_IFLG_PAUSED 0x00010000 + #if IS_ENABLED(CONFIG_SND_HRTIMER) #define DEFAULT_TIMER_LIMIT 4 #else @@ -539,6 +542,10 @@ static int snd_timer_stop1(struct snd_timer_instance *timeri, bool stop) } } timeri->flags &= ~(SNDRV_TIMER_IFLG_RUNNING | SNDRV_TIMER_IFLG_START); + if (stop) + timeri->flags &= ~SNDRV_TIMER_IFLG_PAUSED; + else + timeri->flags |= SNDRV_TIMER_IFLG_PAUSED; snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP : SNDRV_TIMER_EVENT_CONTINUE); unlock: @@ -600,6 +607,10 @@ int snd_timer_stop(struct snd_timer_instance *timeri) */ int snd_timer_continue(struct snd_timer_instance *timeri) { + /* timer can continue only after pause */ + if (!(timeri->flags & SNDRV_TIMER_IFLG_PAUSED)) + return -EINVAL; + if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) return snd_timer_start_slave(timeri, false); else @@ -1831,6 +1842,9 @@ static int snd_timer_user_continue(struct file *file) tu = file->private_data; if (!tu->timeri) return -EBADFD; + /* start timer instead of continue if it's not used before */ + if (!(tu->timeri->flags & SNDRV_TIMER_IFLG_PAUSED)) + return snd_timer_user_start(file); tu->timeri->lost = 0; return (err = snd_timer_continue(tu->timeri)) < 0 ? err : 0; } -- cgit v1.2.3 From 816f318b2364262a51024096da7ca3b84e78e3b5 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 30 Aug 2016 14:45:46 +0200 Subject: ALSA: rawmidi: Fix possible deadlock with virmidi registration When a seq-virmidi driver is initialized, it registers a rawmidi instance with its callback to create an associated seq kernel client. Currently it's done throughly in rawmidi's register_mutex context. Recently it was found that this may lead to a deadlock another rawmidi device that is being attached with the sequencer is accessed, as both open with the same register_mutex. This was actually triggered by syzkaller, as Dmitry Vyukov reported: ====================================================== [ INFO: possible circular locking dependency detected ] 4.8.0-rc1+ #11 Not tainted ------------------------------------------------------- syz-executor/7154 is trying to acquire lock: (register_mutex#5){+.+.+.}, at: [] snd_rawmidi_kernel_open+0x4b/0x260 sound/core/rawmidi.c:341 but task is already holding lock: (&grp->list_mutex){++++.+}, at: [] check_and_subscribe_port+0x5b/0x5c0 sound/core/seq/seq_ports.c:495 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&grp->list_mutex){++++.+}: [] lock_acquire+0x208/0x430 kernel/locking/lockdep.c:3746 [] down_read+0x49/0xc0 kernel/locking/rwsem.c:22 [< inline >] deliver_to_subscribers sound/core/seq/seq_clientmgr.c:681 [] snd_seq_deliver_event+0x35e/0x890 sound/core/seq/seq_clientmgr.c:822 [] > snd_seq_kernel_client_dispatch+0x126/0x170 sound/core/seq/seq_clientmgr.c:2418 [] snd_seq_system_broadcast+0xb2/0xf0 sound/core/seq/seq_system.c:101 [] snd_seq_create_kernel_client+0x24a/0x330 sound/core/seq/seq_clientmgr.c:2297 [< inline >] snd_virmidi_dev_attach_seq sound/core/seq/seq_virmidi.c:383 [] snd_virmidi_dev_register+0x29f/0x750 sound/core/seq/seq_virmidi.c:450 [] snd_rawmidi_dev_register+0x30c/0xd40 sound/core/rawmidi.c:1645 [] __snd_device_register.part.0+0x63/0xc0 sound/core/device.c:164 [< inline >] __snd_device_register sound/core/device.c:162 [] snd_device_register_all+0xad/0x110 sound/core/device.c:212 [] snd_card_register+0xef/0x6c0 sound/core/init.c:749 [] snd_virmidi_probe+0x3ef/0x590 sound/drivers/virmidi.c:123 [] platform_drv_probe+0x8b/0x170 drivers/base/platform.c:564 ...... -> #0 (register_mutex#5){+.+.+.}: [< inline >] check_prev_add kernel/locking/lockdep.c:1829 [< inline >] check_prevs_add kernel/locking/lockdep.c:1939 [< inline >] validate_chain kernel/locking/lockdep.c:2266 [] __lock_acquire+0x4d44/0x4d80 kernel/locking/lockdep.c:3335 [] lock_acquire+0x208/0x430 kernel/locking/lockdep.c:3746 [< inline >] __mutex_lock_common kernel/locking/mutex.c:521 [] mutex_lock_nested+0xb1/0xa20 kernel/locking/mutex.c:621 [] snd_rawmidi_kernel_open+0x4b/0x260 sound/core/rawmidi.c:341 [] midisynth_subscribe+0xf7/0x350 sound/core/seq/seq_midi.c:188 [< inline >] subscribe_port sound/core/seq/seq_ports.c:427 [] check_and_subscribe_port+0x467/0x5c0 sound/core/seq/seq_ports.c:510 [] snd_seq_port_connect+0x2c9/0x500 sound/core/seq/seq_ports.c:579 [] snd_seq_ioctl_subscribe_port+0x1d8/0x2b0 sound/core/seq/seq_clientmgr.c:1480 [] snd_seq_do_ioctl+0x184/0x1e0 sound/core/seq/seq_clientmgr.c:2225 [] snd_seq_kernel_client_ctl+0xa8/0x110 sound/core/seq/seq_clientmgr.c:2440 [] snd_seq_oss_midi_open+0x3b4/0x610 sound/core/seq/oss/seq_oss_midi.c:375 [] snd_seq_oss_synth_setup_midi+0x107/0x4c0 sound/core/seq/oss/seq_oss_synth.c:281 [] snd_seq_oss_open+0x748/0x8d0 sound/core/seq/oss/seq_oss_init.c:274 [] odev_open+0x6a/0x90 sound/core/seq/oss/seq_oss.c:138 [] soundcore_open+0x30f/0x640 sound/sound_core.c:639 ...... other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&grp->list_mutex); lock(register_mutex#5); lock(&grp->list_mutex); lock(register_mutex#5); *** DEADLOCK *** ====================================================== The fix is to simply move the registration parts in snd_rawmidi_dev_register() to the outside of the register_mutex lock. The lock is needed only to manage the linked list, and it's not necessarily to cover the whole initialization process. Reported-by: Dmitry Vyukov Cc: Signed-off-by: Takashi Iwai --- sound/core/rawmidi.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'sound/core') diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c index 795437b10082..b450a27588c8 100644 --- a/sound/core/rawmidi.c +++ b/sound/core/rawmidi.c @@ -1633,11 +1633,13 @@ static int snd_rawmidi_dev_register(struct snd_device *device) return -EBUSY; } list_add_tail(&rmidi->list, &snd_rawmidi_devices); + mutex_unlock(®ister_mutex); err = snd_register_device(SNDRV_DEVICE_TYPE_RAWMIDI, rmidi->card, rmidi->device, &snd_rawmidi_f_ops, rmidi, &rmidi->dev); if (err < 0) { rmidi_err(rmidi, "unable to register\n"); + mutex_lock(®ister_mutex); list_del(&rmidi->list); mutex_unlock(®ister_mutex); return err; @@ -1645,6 +1647,7 @@ static int snd_rawmidi_dev_register(struct snd_device *device) if (rmidi->ops && rmidi->ops->dev_register && (err = rmidi->ops->dev_register(rmidi)) < 0) { snd_unregister_device(&rmidi->dev); + mutex_lock(®ister_mutex); list_del(&rmidi->list); mutex_unlock(®ister_mutex); return err; @@ -1677,7 +1680,6 @@ static int snd_rawmidi_dev_register(struct snd_device *device) } } #endif /* CONFIG_SND_OSSEMUL */ - mutex_unlock(®ister_mutex); sprintf(name, "midi%d", rmidi->device); entry = snd_info_create_card_entry(rmidi->card, name, rmidi->card->proc_root); if (entry) { -- cgit v1.2.3