Commit c3afa2a4 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: core: Fix double-free at snd_card_new() 



During the code change to add the support for devres-managed card
instance, we put an explicit kfree(card) call at the error path in
snd_card_new().  This is needed for the early error path before the
card is initialized with the device, but is rather superfluous and
causes a double-free at the error path after the card instance is
initialized, as the destructor of the card object already contains a
kfree() call.

This patch fixes the double-free situation by removing the superfluous
kfree().  Meanwhile we need to call kfree() explicitly for the early
error path, so it's added there instead.

Fixes: e8ad415b ("ALSA: core: Add managed card creation")
Reported-by: default avatarRondreis <linhaoguo86@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/CAB7eexL1zBnB636hwS27d-LdPYZ_R1-5fJS_h=ZbCWYU=UPWJg@mail.gmail.com
Link: https://lore.kernel.org/r/20220919123516.28222-1-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 49632230

sound/core/init.c

+5 −5
Original line number Diff line number Diff line
@@ -178,10 +178,8 @@ int snd_card_new(struct device *parent, int idx, const char *xid, 
		return -ENOMEM;



	err = snd_card_init(card, parent, idx, xid, module, extra_size);

	if (err < 0) {

		kfree(card);

		return err;

	}

	if (err < 0)

		return err; /* card is freed by error handler */



	*card_ret = card;

	return 0;
@@ -233,7 +231,7 @@ int snd_devm_card_new(struct device *parent, int idx, const char *xid, 
	card->managed = true;

	err = snd_card_init(card, parent, idx, xid, module, extra_size);

	if (err < 0) {

		devres_free(card);

		devres_free(card); /* in managed mode, we need to free manually */

		return err;

	}
@@ -297,6 +295,8 @@ static int snd_card_init(struct snd_card *card, struct device *parent, 
		mutex_unlock(&snd_card_mutex);

		dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n",

			 idx, snd_ecards_limit - 1, err);

		if (!card->managed)

			kfree(card); /* manually free here, as no destructor called */

		return err;

	}

	set_bit(idx, snd_cards_lock);		/* lock it */