From 0c264af7be2013266c5b4c644f3f366399ee490a Mon Sep 17 00:00:00 2001 From: Takashi Sakamoto Date: Sun, 20 Aug 2017 15:54:26 +0900 Subject: [PATCH] ALSA: firewire: fix NULL pointer dereference when releasing uninitialized data of iso-resource When calling 'iso_resource_free()' for uninitialized data, this function causes NULL pointer dereference due to its 'unit' member. This occurs when unplugging audio and music units on IEEE 1394 bus at failure of card registration. This commit fixes the bug. The bug exists since kernel v4.5. Fixes: 324540c4e05c ('ALSA: fireface: postpone sound card registration') at v4.12 Fixes: 8865a31e0fd8 ('ALSA: firewire-motu: postpone sound card registration') at v4.12 Fixes: b610386c8afb ('ALSA: firewire-tascam: deleyed registration of sound card') at v4.7 Fixes: 86c8dd7f4da3 ('ALSA: firewire-digi00x: delayed registration of sound card') at v4.7 Fixes: 6c29230e2a5f ('ALSA: oxfw: delayed registration of sound card') at v4.7 Fixes: 7d3c1d5901aa ('ALSA: fireworks: delayed registration of sound card') at v4.7 Fixes: 04a2c73c97eb ('ALSA: bebob: delayed registration of sound card') at v4.7 Fixes: b59fb1900b4f ('ALSA: dice: postpone card registration') at v4.5 Cc: # v4.5+ Signed-off-by: Takashi Sakamoto Signed-off-by: Takashi Iwai --- sound/firewire/iso-resources.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/sound/firewire/iso-resources.c b/sound/firewire/iso-resources.c index f0e4d502d604..066b5df666f4 100644 --- a/sound/firewire/iso-resources.c +++ b/sound/firewire/iso-resources.c @@ -210,9 +210,14 @@ EXPORT_SYMBOL(fw_iso_resources_update); */ void fw_iso_resources_free(struct fw_iso_resources *r) { - struct fw_card *card = fw_parent_device(r->unit)->card; + struct fw_card *card; int bandwidth, channel; + /* Not initialized. */ + if (r->unit == NULL) + return; + card = fw_parent_device(r->unit)->card; + mutex_lock(&r->mutex); if (r->allocated) {