From c3afa2a402d1ecefa59f88d55d9e765f52f75bd9 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Mon, 19 Sep 2022 14:35:16 +0200 Subject: [PATCH] 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: e8ad415b7a55 ("ALSA: core: Add managed card creation") Reported-by: Rondreis Cc: 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 --- sound/core/init.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/sound/core/init.c b/sound/core/init.c index 193dae3..5377f94 100644 --- a/sound/core/init.c +++ b/sound/core/init.c @@ -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 */ -- 2.7.4