A crash can occur on some platforms where adsp is enumerated but codec
is not matched. Check that the codec_id string is valid before
attempting to match.
Signed-off-by: Kevin Strasser <[email protected]>
---
sound/soc/intel/sst/sst_acpi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/soc/intel/sst/sst_acpi.c b/sound/soc/intel/sst/sst_acpi.c
index 31124aa..dd72e58 100644
--- a/sound/soc/intel/sst/sst_acpi.c
+++ b/sound/soc/intel/sst/sst_acpi.c
@@ -236,7 +236,7 @@ static struct sst_machines *sst_acpi_find_machine(
struct sst_machines *mach;
bool found = false;
- for (mach = machines; mach->codec_id; mach++)
+ for (mach = machines; mach->codec_id[0]; mach++)
if (ACPI_SUCCESS(acpi_get_devices(mach->codec_id,
sst_acpi_mach_match,
&found, NULL)) && found)
--
1.9.1
On Wed, Dec 10, 2014 at 11:21:57PM -0800, Kevin Strasser wrote:
> A crash can occur on some platforms where adsp is enumerated but codec
> is not matched. Check that the codec_id string is valid before
> attempting to match.
> - for (mach = machines; mach->codec_id; mach++)
> + for (mach = machines; mach->codec_id[0]; mach++)
This changes the check from verifying if a codec_id is present to
verifying if the first character in the codec_id is non-NULL. That
doesn't seem obviously safer and the tables of machines seem to be
terminated by having an entry with all fields set to zero (which is
a common idiom in Linux) which would now crash with this change.
> -----Original Message-----
> From: Mark Brown [mailto:[email protected]]
> Sent: Thursday, December 11, 2014 5:20 AM>
> On Wed, Dec 10, 2014 at 11:21:57PM -0800, Kevin Strasser wrote:
>
> > A crash can occur on some platforms where adsp is enumerated but codec
> > is not matched. Check that the codec_id string is valid before
> > attempting to match.
>
> > - for (mach = machines; mach->codec_id; mach++)
> > + for (mach = machines; mach->codec_id[0]; mach++)
>
> This changes the check from verifying if a codec_id is present to verifying if
> the first character in the codec_id is non-NULL. That doesn't seem obviously
> safer and the tables of machines seem to be terminated by having an entry
> with all fields set to zero (which is a common idiom in Linux) which would
> now crash with this change.
In this case mach->codec_id is non-NULL, even for the terminating element, because it
is defined to be a fixed width. So we have to take a look at the first character to see if it
has been initialized.
-Kevin
On Thu, Dec 11, 2014 at 09:55:38PM +0000, Strasser, Kevin wrote:
Please fix your mailer to word wrap comfortably under 80 colums so that
your mails are easily legible.
> > This changes the check from verifying if a codec_id is present to verifying if
> > the first character in the codec_id is non-NULL. That doesn't seem obviously
> > safer and the tables of machines seem to be terminated by having an entry
> > with all fields set to zero (which is a common idiom in Linux) which would
> > now crash with this change.
> In this case mach->codec_id is non-NULL, even for the terminating element, because it
> is defined to be a fixed width. So we have to take a look at the first character to see if it
> has been initialized.
That's a really unusual and (as you've seen) error prone idiom - is it
not better to fix the struct to use the more common idiom?
On Mon, Dec 15, 2014 at 05:06:45PM +0000, Mark Brown wrote:
> Please fix your mailer to word wrap comfortably under 80 colums so that your
> mails are easily legible.
Understood
> > > This changes the check from verifying if a codec_id is present to
> > > verifying if the first character in the codec_id is non-NULL. That
> > > doesn't seem obviously safer and the tables of machines seem to be
> > > terminated by having an entry with all fields set to zero (which is a
> > > common idiom in Linux) which would now crash with this change.
>
> > In this case mach->codec_id is non-NULL, even for the terminating element,
> > because it is defined to be a fixed width. So we have to take a look at the
> > first character to see if it has been initialized.
>
> That's a really unusual and (as you've seen) error prone idiom - is it not
> better to fix the struct to use the more common idiom?
That seems like a good idea to me. I'll prepare a new patch to change the
sst_machines definition so that codec_id gets initialized to NULL.
-Kevin
A crash can occur on some platforms where adsp is enumerated but codec is not
matched. Define codec_id as a pointer intead of an array so that it gets
initialized to NULL for the terminating element of sst_acpi_bytcr[] and
sst_acpi_chv[].
Signed-off-by: Kevin Strasser <[email protected]>
---
sound/soc/intel/sst/sst_acpi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/soc/intel/sst/sst_acpi.c b/sound/soc/intel/sst/sst_acpi.c
index 31124aa..87b5090 100644
--- a/sound/soc/intel/sst/sst_acpi.c
+++ b/sound/soc/intel/sst/sst_acpi.c
@@ -43,7 +43,7 @@
#include "sst.h"
struct sst_machines {
- char codec_id[32];
+ char *codec_id;
char board[32];
char machine[32];
void (*machine_quirk)(void);
--
1.9.1
On Mon, Dec 15, 2014 at 04:15:04PM -0800, Kevin Strasser wrote:
> A crash can occur on some platforms where adsp is enumerated but codec is not
> matched. Define codec_id as a pointer intead of an array so that it gets
> initialized to NULL for the terminating element of sst_acpi_bytcr[] and
> sst_acpi_chv[].
Applied, thanks.