From 6d08d17831b8e9fd8f14292cfde9c5df165e5459 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Thu, 4 Feb 2016 15:59:43 -0200 Subject: [PATCH] saa7134-alsa: Only frees registered sound cards commit ac75fe5d8fe4a0bf063be18fb29684405279e79e upstream. That prevents this bug: [ 2382.269496] BUG: unable to handle kernel NULL pointer dereference at 0000000000000540 [ 2382.270013] IP: [] snd_card_free+0x36/0x70 [snd] [ 2382.270013] PGD 0 [ 2382.270013] Oops: 0002 [#1] SMP [ 2382.270013] Modules linked in: saa7134_alsa(-) tda1004x saa7134_dvb videobuf2_dvb dvb_core tda827x tda8290 tuner saa7134 tveeprom videobuf2_dma_sg videobuf2_memops videobuf2_v4l2 videobuf2_core v4l2_common videodev media auth_rpcgss nfsv4 dns_resolver nfs lockd grace sunrpc tun bridge stp llc ebtables ip6table_filter ip6_tables nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack it87 hwmon_vid snd_hda_codec_idt snd_hda_codec_generic iTCO_wdt iTCO_vendor_support snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core snd_seq pcspkr i2c_i801 snd_seq_device snd_pcm snd_timer lpc_ich snd mfd_core soundcore binfmt_misc i915 video i2c_algo_bit drm_kms_helper drm r8169 ata_generic serio_raw pata_acpi mii i2c_core [last unloaded: videobuf2_memops] [ 2382.270013] CPU: 0 PID: 4899 Comm: rmmod Not tainted 4.5.0-rc1+ #4 [ 2382.270013] Hardware name: PCCHIPS P17G/P17G, BIOS 080012 05/14/2008 [ 2382.270013] task: ffff880039c38000 ti: ffff88003c764000 task.ti: ffff88003c764000 [ 2382.270013] RIP: 0010:[] [] snd_card_free+0x36/0x70 [snd] [ 2382.270013] RSP: 0018:ffff88003c767ea0 EFLAGS: 00010286 [ 2382.270013] RAX: ffff88003c767eb8 RBX: 0000000000000000 RCX: 0000000000006260 [ 2382.270013] RDX: ffffffffa020a060 RSI: ffffffffa0206de1 RDI: ffff88003c767eb0 [ 2382.270013] RBP: ffff88003c767ed8 R08: 0000000000019960 R09: ffffffff811a5412 [ 2382.270013] R10: ffffea0000d7c200 R11: 0000000000000000 R12: ffff88003c767ea8 [ 2382.270013] R13: 00007ffe760617f7 R14: 0000000000000000 R15: 0000557625d7f1e0 [ 2382.270013] FS: 00007f80bb1c0700(0000) GS:ffff88003f400000(0000) knlGS:0000000000000000 [ 2382.270013] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 2382.270013] CR2: 0000000000000540 CR3: 000000003c00f000 CR4: 00000000000006f0 [ 2382.270013] Stack: [ 2382.270013] 000000003c767ed8 ffffffff00000000 ffff880000000000 ffff88003c767eb8 [ 2382.270013] ffff88003c767eb8 ffffffffa049a890 00007ffe76060060 ffff88003c767ef0 [ 2382.270013] ffffffffa049889d ffffffffa049a500 ffff88003c767f48 ffffffff8111079c [ 2382.270013] Call Trace: [ 2382.270013] [] saa7134_alsa_exit+0x1d/0x780 [saa7134_alsa] [ 2382.270013] [] SyS_delete_module+0x19c/0x1f0 [ 2382.270013] [] entry_SYSCALL_64_fastpath+0x12/0x71 [ 2382.270013] Code: 20 a0 48 c7 c6 e1 6d 20 a0 48 89 e5 41 54 53 4c 8d 65 d0 48 89 fb 48 83 ec 28 c7 45 d0 00 00 00 00 49 8d 7c 24 08 e8 7a 55 ed e0 <4c> 89 a3 40 05 00 00 48 89 df e8 eb fd ff ff 85 c0 75 1a 48 8d [ 2382.270013] RIP [] snd_card_free+0x36/0x70 [snd] [ 2382.270013] RSP [ 2382.270013] CR2: 0000000000000540 Signed-off-by: Mauro Carvalho Chehab [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings --- drivers/media/video/saa7134/saa7134-alsa.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/media/video/saa7134/saa7134-alsa.c b/drivers/media/video/saa7134/saa7134-alsa.c index dbcdfbf8aed0..11b0ef3a2858 100644 --- a/drivers/media/video/saa7134/saa7134-alsa.c +++ b/drivers/media/video/saa7134/saa7134-alsa.c @@ -1145,6 +1145,8 @@ static int alsa_device_init(struct saa7134_dev *dev) static int alsa_device_exit(struct saa7134_dev *dev) { + if (!snd_saa7134_cards[dev->nr]) + return 1; snd_card_free(snd_saa7134_cards[dev->nr]); snd_saa7134_cards[dev->nr] = NULL; @@ -1194,7 +1196,8 @@ static void saa7134_alsa_exit(void) int idx; for (idx = 0; idx < SNDRV_CARDS; idx++) { - snd_card_free(snd_saa7134_cards[idx]); + if (snd_saa7134_cards[idx]) + snd_card_free(snd_saa7134_cards[idx]); } saa7134_dmasound_init = NULL; -- 2.39.2