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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: e8ad415b7a ("ALSA: core: Add managed card creation")
Reported-by: Rondreis <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: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2022-09-19 14:35:16 +02:00
parent 496322302b
commit c3afa2a402
1 changed files with 5 additions and 5 deletions
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10
sound/core/init.c
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@ -178,10 +178,8 @@ int snd_card_new(struct device *parent, int idx, const char *xid,
return -ENOMEM; return -ENOMEM;
err = snd_card_init(card, parent, idx, xid, module, extra_size); err = snd_card_init(card, parent, idx, xid, module, extra_size);
if (err < 0) { if (err < 0)
kfree(card); return err; /* card is freed by error handler */
return err;
}
*card_ret = card; *card_ret = card;
return 0; return 0;
@ -233,7 +231,7 @@ int snd_devm_card_new(struct device *parent, int idx, const char *xid,
card->managed = true; card->managed = true;
err = snd_card_init(card, parent, idx, xid, module, extra_size); err = snd_card_init(card, parent, idx, xid, module, extra_size);
if (err < 0) { if (err < 0) {
devres_free(card); devres_free(card); /* in managed mode, we need to free manually */
return err; return err;
} }
@ -297,6 +295,8 @@ static int snd_card_init(struct snd_card *card, struct device *parent,
mutex_unlock(&snd_card_mutex); mutex_unlock(&snd_card_mutex);
dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n", dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n",
idx, snd_ecards_limit - 1, err); idx, snd_ecards_limit - 1, err);
if (!card->managed)
kfree(card); /* manually free here, as no destructor called */
return err; return err;
} }
set_bit(idx, snd_cards_lock); /* lock it */ set_bit(idx, snd_cards_lock); /* lock it */