Right now, the machine devices are created early, before the
SST context is initialized. This means that SST might not be
fully initialized if sst_acpi_probe() fails later on (e.g. after
sst_platform_get_resources() if the IRQ does not exist).
However, at least sst-mfld-platform assumes that sst_register_dsp()
was called to set the (global) "sst" device pointer, which happens
only later in sst_acpi_probe() when sst_context_init() is called.
This may cause a NULL pointer dereference later when the ALSA device
is first opened:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 0 PID: 790 Comm: pulseaudio Not tainted 4.20.0-rc6-mainline-00161-g6531e115b7ab #1
Hardware name: ASUSTeK COMPUTER INC. ME176C/ME176C, BIOS 5.6.5 09/16/2015
RIP: 0010:sst_handle_vb_timer+0x61/0x1b0 [snd_soc_sst_atom_hifi2_platform]
Code: 44 24 04 e9 84 00 00 00 31 c9 c7 04 24 ff ff ff ff 66 89 4c 24 06 84 db 0f 84 90 00 00 00 48 8b 05 c4 23 01 00 be 01 00 00 00 <48> 8b 78 08 48 8b 40 10 48 8b 40 48 e8 2e 5e d7 f0 89 c3 85 c0 78
RSP: 0018:ffff9d968099fa30 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000080000001 RSI: 0000000000000001 RDI: 00000000ffffffff
RBP: ffff968d33384618 R08: 0000000000000001 R09: 00000000000002e3
R10: ffff968d333a0800 R11: 0000000000000000 R12: ffff968d34bc7c00
R13: ffff968d333a3eb0 R14: 0000000000000001 R15: ffff968d333a08c0
FS: 00007f63a7e7b200(0000) GS:ffff968d37600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 00000000297b8000 CR4: 00000000001006f0
Call Trace:
sst_enable_ssp+0x24/0x40 [snd_soc_sst_atom_hifi2_platform]
soc_pcm_open+0xeb/0x960 [snd_soc_core]
? __debugfs_create_file+0xcd/0x120
dpcm_be_dai_startup+0x183/0x3c0 [snd_soc_core]
dpcm_fe_dai_open+0x10c/0xab0 [snd_soc_core]
snd_pcm_open_substream+0x7f/0x140 [snd_pcm]
snd_pcm_open+0xe6/0x220 [snd_pcm]
? wake_up_q+0x70/0x70
snd_pcm_playback_open+0x3d/0x70 [snd_pcm]
chrdev_open+0xa3/0x1b0
? cdev_put.part.0+0x20/0x20
do_dentry_open+0x12f/0x350
path_openat+0x2d1/0x14e0
? inotify_handle_event+0x17b/0x1e0
do_filp_open+0x93/0x100
? snd_card_file_remove+0x14b/0x170 [snd]
? __check_object_size+0x102/0x189
? _raw_spin_unlock+0x12/0x30
do_sys_open+0x186/0x210
do_syscall_64+0x55/0x160
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f63a992f4c2
Code: 25 00 00 41 00 3d 00 00 41 00 74 4c 48 8d 05 85 70 0d 00 8b 00 85 c0 75 6d 89 f2 b8 01 01 00 00 48 89 fe bf 9c ff ff ff 0f 05 <48> 3d 00 f0 ff ff 0f 87 a2 00 00 00 48 8b 4c 24 28 64 48 33 0c 25
RSP: 002b:00007ffe71196b70 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000080802 RCX: 00007f63a992f4c2
RDX: 0000000000080802 RSI: 00007ffe71196d20 RDI: 00000000ffffff9c
RBP: 00000000ffffffff R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe71196c00
R13: 0000000000000004 R14: 00007ffe71196d20 R15: 0000558466055a80
CR2: 0000000000000008
---[ end trace 34534a02650ee26c ]---
This can be avoided if the machine device creation is delayed
in sst_acpi_probe() until after sst_context_init(), when
sst_register_dsp() is guaranteed to have already been called.
Signed-off-by: Stephan Gerhold <stephan@xxxxxxxxxxx>
---
An other option to fix this would be to add proper NULL checks
in the probe method of sst-mfld-platform and/or sst_enable_ssp().
Maybe this should be done additionally, but at least in my opinion
there is not much point in registering the machine devices if they
end up being broken anyway.
sound/soc/intel/atom/sst/sst_acpi.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/sound/soc/intel/atom/sst/sst_acpi.c b/sound/soc/intel/atom/sst/sst_acpi.c
index ac542535b9d5..493d32923815 100644
--- a/sound/soc/intel/atom/sst/sst_acpi.c
+++ b/sound/soc/intel/atom/sst/sst_acpi.c
@@ -345,6 +345,18 @@ static int sst_acpi_probe(struct platform_device *pdev)
mach->mach_params.acpi_ipc_irq_index =
pdata->res_info->acpi_ipc_irq_index;
+ /* Fill sst platform data */
+ ctx->pdata = pdata;
+ strcpy(ctx->firmware_name, mach->fw_filename);
+
+ ret = sst_platform_get_resources(ctx);
+ if (ret)
+ return ret;
+
+ ret = sst_context_init(ctx);
+ if (ret < 0)
+ return ret;
+
plat_dev = platform_device_register_data(dev, pdata->platform, -1,
NULL, 0);
if (IS_ERR(plat_dev)) {
@@ -365,18 +377,6 @@ static int sst_acpi_probe(struct platform_device *pdev)
return PTR_ERR(mdev);
}
- /* Fill sst platform data */
- ctx->pdata = pdata;
- strcpy(ctx->firmware_name, mach->fw_filename);
-
- ret = sst_platform_get_resources(ctx);
- if (ret)
- return ret;
-
- ret = sst_context_init(ctx);
- if (ret < 0)
- return ret;
-
sst_configure_runtime_pm(ctx);
platform_set_drvdata(pdev, ctx);
return ret;
--
2.20.0
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