[alsa-devel] [PATCH] ALSA: usb-audio: Fix memory leak in __snd_usbmidi_create
In the implementation of __snd_usbmidi_create() there is a memory leak caused by incorrect goto destination. Go to free_midi if snd_usbmidi_create_endpoints_midiman() or snd_usbmidi_create_endpoints() fail.
Fixes: 731209cc0417 ("ALSA: usb-midi: Use common error handling code in __snd_usbmidi_create()") Signed-off-by: Navid Emamdoost navid.emamdoost@gmail.com --- sound/usb/midi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/usb/midi.c b/sound/usb/midi.c index b737f0ec77d0..22db37fbfbbd 100644 --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -2476,7 +2476,7 @@ int __snd_usbmidi_create(struct snd_card *card, else err = snd_usbmidi_create_endpoints(umidi, endpoints); if (err < 0) - goto exit; + goto free_midi;
usb_autopm_get_interface_no_resume(umidi->iface);
On Sun, 27 Oct 2019 23:10:06 +0100, Navid Emamdoost wrote:
In the implementation of __snd_usbmidi_create() there is a memory leak caused by incorrect goto destination. Go to free_midi if snd_usbmidi_create_endpoints_midiman() or snd_usbmidi_create_endpoints() fail.
No, this will lead to double-free. After registering the rawmidi interface at snd_usbmidi_create_rawmidi(), the common destructor will be called via rawmidi private_free callback, and this will release the all resources already.
thanks,
Takashi
Fixes: 731209cc0417 ("ALSA: usb-midi: Use common error handling code in __snd_usbmidi_create()") Signed-off-by: Navid Emamdoost navid.emamdoost@gmail.com
sound/usb/midi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/usb/midi.c b/sound/usb/midi.c index b737f0ec77d0..22db37fbfbbd 100644 --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -2476,7 +2476,7 @@ int __snd_usbmidi_create(struct snd_card *card, else err = snd_usbmidi_create_endpoints(umidi, endpoints); if (err < 0)
goto exit;
goto free_midi;usb_autopm_get_interface_no_resume(umidi->iface);
-- 2.17.1
Thanks for the explanation,
On Mon, Oct 28, 2019 at 1:27 AM Takashi Iwai tiwai@suse.de wrote:
On Sun, 27 Oct 2019 23:10:06 +0100, Navid Emamdoost wrote:
In the implementation of __snd_usbmidi_create() there is a memory leak caused by incorrect goto destination. Go to free_midi if snd_usbmidi_create_endpoints_midiman() or snd_usbmidi_create_endpoints() fail.
No, this will lead to double-free. After registering the rawmidi interface at snd_usbmidi_create_rawmidi(), the common destructor will be called via rawmidi private_free callback, and this will release the all resources already.
Now I can see how rawmidi private_free is set up to release the resources, but what concerns me is that at the moment of endpoint/port creation umidi is not yet added to the midi_list. In other words, what I see is that we still have just one local pointer to umidi if any of snd_usbmidi_create_endpoint* fail. Am I missing something?
thanks,
Takashi
Fixes: 731209cc0417 ("ALSA: usb-midi: Use common error handling code in __snd_usbmidi_create()") Signed-off-by: Navid Emamdoost navid.emamdoost@gmail.com
sound/usb/midi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/usb/midi.c b/sound/usb/midi.c index b737f0ec77d0..22db37fbfbbd 100644 --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -2476,7 +2476,7 @@ int __snd_usbmidi_create(struct snd_card *card, else err = snd_usbmidi_create_endpoints(umidi, endpoints); if (err < 0)
goto exit;
goto free_midi; usb_autopm_get_interface_no_resume(umidi->iface);-- 2.17.1
On Mon, 28 Oct 2019 17:25:41 +0100, Navid Emamdoost wrote:
Thanks for the explanation,
On Mon, Oct 28, 2019 at 1:27 AM Takashi Iwai tiwai@suse.de wrote:
On Sun, 27 Oct 2019 23:10:06 +0100, Navid Emamdoost wrote:
In the implementation of __snd_usbmidi_create() there is a memory leak caused by incorrect goto destination. Go to free_midi if snd_usbmidi_create_endpoints_midiman() or snd_usbmidi_create_endpoints() fail.
No, this will lead to double-free. After registering the rawmidi interface at snd_usbmidi_create_rawmidi(), the common destructor will be called via rawmidi private_free callback, and this will release the all resources already.
Now I can see how rawmidi private_free is set up to release the resources, but what concerns me is that at the moment of endpoint/port creation umidi is not yet added to the midi_list. In other words, what I see is that we still have just one local pointer to umidi if any of snd_usbmidi_create_endpoint* fail. Am I missing something?
The rawmidi object that is created via snd_rawmidi_new() is managed via snd_device list, and it's traversed at snd_card_disconnect() and snd_card_free() calls. It's something like devm-stuff (but implemented in a different way). The midi_list is an explicit list for the USB MIDI driver, and it's an individual one from the device list.
Takashi
thanks,
Takashi
Fixes: 731209cc0417 ("ALSA: usb-midi: Use common error handling code in __snd_usbmidi_create()") Signed-off-by: Navid Emamdoost navid.emamdoost@gmail.com
sound/usb/midi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/usb/midi.c b/sound/usb/midi.c index b737f0ec77d0..22db37fbfbbd 100644 --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -2476,7 +2476,7 @@ int __snd_usbmidi_create(struct snd_card *card, else err = snd_usbmidi_create_endpoints(umidi, endpoints); if (err < 0)
goto exit;
goto free_midi; usb_autopm_get_interface_no_resume(umidi->iface);-- 2.17.1
-- Navid.
On Mon, Oct 28, 2019 at 11:38 AM Takashi Iwai tiwai@suse.de wrote:
On Mon, 28 Oct 2019 17:25:41 +0100, Navid Emamdoost wrote:
Thanks for the explanation,
On Mon, Oct 28, 2019 at 1:27 AM Takashi Iwai tiwai@suse.de wrote:
On Sun, 27 Oct 2019 23:10:06 +0100, Navid Emamdoost wrote:
In the implementation of __snd_usbmidi_create() there is a memory leak caused by incorrect goto destination. Go to free_midi if snd_usbmidi_create_endpoints_midiman() or snd_usbmidi_create_endpoints() fail.
No, this will lead to double-free. After registering the rawmidi interface at snd_usbmidi_create_rawmidi(), the common destructor will be called via rawmidi private_free callback, and this will release the all resources already.
Now I can see how rawmidi private_free is set up to release the resources, but what concerns me is that at the moment of endpoint/port creation umidi is not yet added to the midi_list. In other words, what I see is that we still have just one local pointer to umidi if any of snd_usbmidi_create_endpoint* fail. Am I missing something?
The rawmidi object that is created via snd_rawmidi_new() is managed via snd_device list, and it's traversed at snd_card_disconnect() and snd_card_free() calls. It's something like devm-stuff (but implemented in a different way). The midi_list is an explicit list for the USB MIDI driver, and it's an individual one from the device list.
Thanks for the clarification.
Takashi
thanks,
Takashi
Fixes: 731209cc0417 ("ALSA: usb-midi: Use common error handling code in __snd_usbmidi_create()") Signed-off-by: Navid Emamdoost navid.emamdoost@gmail.com
sound/usb/midi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/usb/midi.c b/sound/usb/midi.c index b737f0ec77d0..22db37fbfbbd 100644 --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -2476,7 +2476,7 @@ int __snd_usbmidi_create(struct snd_card *card, else err = snd_usbmidi_create_endpoints(umidi, endpoints); if (err < 0)
goto exit;
goto free_midi; usb_autopm_get_interface_no_resume(umidi->iface);-- 2.17.1
-- Navid.
Navid Emamdoost wrote:
On Mon, Oct 28, 2019 at 1:27 AM Takashi Iwai tiwai@suse.de wrote:
On Sun, 27 Oct 2019 23:10:06 +0100, Navid Emamdoost wrote:
In the implementation of __snd_usbmidi_create() there is a memory leak caused by incorrect goto destination. Go to free_midi if snd_usbmidi_create_endpoints_midiman() or snd_usbmidi_create_endpoints() fail.
No, this will lead to double-free. After registering the rawmidi interface at snd_usbmidi_create_rawmidi(), the common destructor will be called via rawmidi private_free callback, and this will release the all resources already.
Now I can see how rawmidi private_free is set up to release the resources, but what concerns me is that at the moment of endpoint/port creation umidi is not yet added to the midi_list. In other words, what I see is that we still have just one local pointer to umidi if any of snd_usbmidi_create_endpoint* fail.
The snd_rawmidi device is automatically registered with the card, so the line "rmidi->private_free = snd_usbmidi_rawmidi_free;" is the exact point where the ownership of umidi changes. midi_list does not matter.
Regards, Clemens
participants (3)
-
Clemens Ladisch -
Navid Emamdoost -
Takashi Iwai