* [PATCH v2] acer-wmi: fix memory leaks in wmab_execute error path
@ 2010-07-09 4:37 Axel Lin
2010-07-13 1:03 ` Axel Lin
2010-07-13 1:35 ` Andrew Morton
0 siblings, 2 replies; 4+ messages in thread
From: Axel Lin @ 2010-07-09 4:37 UTC (permalink / raw)
To: linux-kernel
Cc: Carlos Corbacho, Matthew Garrett, Thomas Renninger, Alan Jenkins,
platform-driver-x86
When acpi_evaluate_object() is passed ACPI_ALLOCATE_BUFFER,
the caller must kfree the returned buffer if AE_OK is returned.
Call Trace:
wmab_execute
-> wmi_evaluate_method
-> acpi_evaluate_object
Thus if callers of wmab_execute() pass ACPI_ALLOCATE_BUFFER,
the return buffer must be kfreed if wmab_execute return AE_OK.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
---
drivers/platform/x86/acer-wmi.c | 11 ++++++++++-
1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c
index 1ea6c43..3f44446 100644
--- a/drivers/platform/x86/acer-wmi.c
+++ b/drivers/platform/x86/acer-wmi.c
@@ -555,6 +555,7 @@ static acpi_status AMW0_find_mailled(void)
obj->buffer.length == sizeof(struct wmab_ret)) {
ret = *((struct wmab_ret *) obj->buffer.pointer);
} else {
+ kfree(out.pointer);
return AE_ERROR;
}
@@ -598,6 +599,7 @@ static acpi_status AMW0_set_capabilities(void)
obj->buffer.length == sizeof(struct wmab_ret)) {
ret = *((struct wmab_ret *) obj->buffer.pointer);
} else {
+ kfree(out.pointer);
return AE_ERROR;
}
@@ -607,15 +609,22 @@ static acpi_status AMW0_set_capabilities(void)
args.ebx = 2 << 8;
args.ebx |= ACER_AMW0_BLUETOOTH_MASK;
+ /*
+ * It's ok to use existing buffer for next wmab_execute call.
+ * But we need to kfree(out.pointer) if next wmab_execute fail.
+ */
status = wmab_execute(&args, &out);
- if (ACPI_FAILURE(status))
+ if (ACPI_FAILURE(status)) {
+ kfree(out.pointer);
return status;
+ }
obj = (union acpi_object *) out.pointer;
if (obj && obj->type == ACPI_TYPE_BUFFER
&& obj->buffer.length == sizeof(struct wmab_ret)) {
ret = *((struct wmab_ret *) obj->buffer.pointer);
} else {
+ kfree(out.pointer);
return AE_ERROR;
}
--
1.5.4.3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] acer-wmi: fix memory leaks in wmab_execute error path
2010-07-09 4:37 [PATCH v2] acer-wmi: fix memory leaks in wmab_execute error path Axel Lin
@ 2010-07-13 1:03 ` Axel Lin
2010-07-13 1:35 ` Andrew Morton
1 sibling, 0 replies; 4+ messages in thread
From: Axel Lin @ 2010-07-13 1:03 UTC (permalink / raw)
To: linux-kernel
Cc: Carlos Corbacho, Matthew Garrett, Thomas Renninger, Alan Jenkins,
platform-driver-x86, Andrew Morton
hi Andrew,
I just found acer-wmi-fix-memory-leaks-in-wmab_execute-error-path.patch added to -mm tree.
But I think the V2 version is the correct one.
If the second wmab_execute fail (for any reason) , we need to free the existing buffer before return status.
Sould I resend the patch?
Regards,
Axel
於 五，2010-07-09 於 12:37 +0800，Axel Lin 提到：
> When acpi_evaluate_object() is passed ACPI_ALLOCATE_BUFFER,
> the caller must kfree the returned buffer if AE_OK is returned.
>
> Call Trace:
> wmab_execute
> -> wmi_evaluate_method
> -> acpi_evaluate_object
>
> Thus if callers of wmab_execute() pass ACPI_ALLOCATE_BUFFER,
> the return buffer must be kfreed if wmab_execute return AE_OK.
>
> Signed-off-by: Axel Lin <axel.lin@gmail.com>
> ---
> drivers/platform/x86/acer-wmi.c | 11 ++++++++++-
> 1 files changed, 10 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c
> index 1ea6c43..3f44446 100644
> --- a/drivers/platform/x86/acer-wmi.c
> +++ b/drivers/platform/x86/acer-wmi.c
> @@ -555,6 +555,7 @@ static acpi_status AMW0_find_mailled(void)
> obj->buffer.length == sizeof(struct wmab_ret)) {
> ret = *((struct wmab_ret *) obj->buffer.pointer);
> } else {
> + kfree(out.pointer);
> return AE_ERROR;
> }
>
> @@ -598,6 +599,7 @@ static acpi_status AMW0_set_capabilities(void)
> obj->buffer.length == sizeof(struct wmab_ret)) {
> ret = *((struct wmab_ret *) obj->buffer.pointer);
> } else {
> + kfree(out.pointer);
> return AE_ERROR;
> }
>
> @@ -607,15 +609,22 @@ static acpi_status AMW0_set_capabilities(void)
> args.ebx = 2 << 8;
> args.ebx |= ACER_AMW0_BLUETOOTH_MASK;
>
> + /*
> + * It's ok to use existing buffer for next wmab_execute call.
> + * But we need to kfree(out.pointer) if next wmab_execute fail.
> + */
> status = wmab_execute(&args, &out);
> - if (ACPI_FAILURE(status))
> + if (ACPI_FAILURE(status)) {
> + kfree(out.pointer);
> return status;
> + }
>
> obj = (union acpi_object *) out.pointer;
> if (obj && obj->type == ACPI_TYPE_BUFFER
> && obj->buffer.length == sizeof(struct wmab_ret)) {
> ret = *((struct wmab_ret *) obj->buffer.pointer);
> } else {
> + kfree(out.pointer);
> return AE_ERROR;
> }
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] acer-wmi: fix memory leaks in wmab_execute error path
2010-07-09 4:37 [PATCH v2] acer-wmi: fix memory leaks in wmab_execute error path Axel Lin
2010-07-13 1:03 ` Axel Lin
@ 2010-07-13 1:35 ` Andrew Morton
2010-07-13 2:14 ` Axel Lin
1 sibling, 1 reply; 4+ messages in thread
From: Andrew Morton @ 2010-07-13 1:35 UTC (permalink / raw)
To: Axel Lin
Cc: linux-kernel, Carlos Corbacho, Matthew Garrett, Thomas Renninger,
Alan Jenkins, platform-driver-x86
On Fri, 09 Jul 2010 12:37:36 +0800 Axel Lin <axel.lin@gmail.com> wrote:
> When acpi_evaluate_object() is passed ACPI_ALLOCATE_BUFFER,
> the caller must kfree the returned buffer if AE_OK is returned.
>
> Call Trace:
> wmab_execute
> -> wmi_evaluate_method
> -> acpi_evaluate_object
>
> Thus if callers of wmab_execute() pass ACPI_ALLOCATE_BUFFER,
> the return buffer must be kfreed if wmab_execute return AE_OK.
>
> Signed-off-by: Axel Lin <axel.lin@gmail.com>
> ---
> drivers/platform/x86/acer-wmi.c | 11 ++++++++++-
> 1 files changed, 10 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c
> index 1ea6c43..3f44446 100644
> --- a/drivers/platform/x86/acer-wmi.c
> +++ b/drivers/platform/x86/acer-wmi.c
> @@ -555,6 +555,7 @@ static acpi_status AMW0_find_mailled(void)
> obj->buffer.length == sizeof(struct wmab_ret)) {
> ret = *((struct wmab_ret *) obj->buffer.pointer);
> } else {
> + kfree(out.pointer);
> return AE_ERROR;
> }
>
> @@ -598,6 +599,7 @@ static acpi_status AMW0_set_capabilities(void)
> obj->buffer.length == sizeof(struct wmab_ret)) {
> ret = *((struct wmab_ret *) obj->buffer.pointer);
> } else {
> + kfree(out.pointer);
> return AE_ERROR;
> }
>
> @@ -607,15 +609,22 @@ static acpi_status AMW0_set_capabilities(void)
> args.ebx = 2 << 8;
> args.ebx |= ACER_AMW0_BLUETOOTH_MASK;
>
> + /*
> + * It's ok to use existing buffer for next wmab_execute call.
> + * But we need to kfree(out.pointer) if next wmab_execute fail.
> + */
> status = wmab_execute(&args, &out);
> - if (ACPI_FAILURE(status))
> + if (ACPI_FAILURE(status)) {
> + kfree(out.pointer);
> return status;
> + }
>
> obj = (union acpi_object *) out.pointer;
> if (obj && obj->type == ACPI_TYPE_BUFFER
> && obj->buffer.length == sizeof(struct wmab_ret)) {
> ret = *((struct wmab_ret *) obj->buffer.pointer);
> } else {
> + kfree(out.pointer);
> return AE_ERROR;
> }
I think it's best to remove the multiple-return-points approach in
favour of the "goto single return point which undoes things" approach.
that way we reduce the risk of later introducing more leaks.
Please review:
From: Andrew Morton <akpm@linux-foundation.org>
avoid multiple return points
remove unneeded cast
remove unneeded initialisation of `status'
Cc: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Cc: Axel Lin <axel.lin@gmail.com>
Cc: Carlos Corbacho <carlos@strangeworlds.co.uk>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Thomas Renninger <trenn@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
drivers/platform/x86/acer-wmi.c | 25 ++++++++++++-------------
1 file changed, 12 insertions(+), 13 deletions(-)
diff -puN drivers/platform/x86/acer-wmi.c~acer-wmi-fix-memory-leaks-in-wmab_execute-error-path-v2-fix drivers/platform/x86/acer-wmi.c
--- a/drivers/platform/x86/acer-wmi.c~acer-wmi-fix-memory-leaks-in-wmab_execute-error-path-v2-fix
+++ a/drivers/platform/x86/acer-wmi.c
@@ -571,7 +571,7 @@ static acpi_status AMW0_set_capabilities
{
struct wmab_args args;
struct wmab_ret ret;
- acpi_status status = AE_OK;
+ acpi_status status;
struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *obj;
@@ -594,13 +594,13 @@ static acpi_status AMW0_set_capabilities
if (ACPI_FAILURE(status))
return status;
- obj = (union acpi_object *) out.pointer;
+ obj = out.pointer;
if (obj && obj->type == ACPI_TYPE_BUFFER &&
obj->buffer.length == sizeof(struct wmab_ret)) {
ret = *((struct wmab_ret *) obj->buffer.pointer);
} else {
- kfree(out.pointer);
- return AE_ERROR;
+ status = AE_ERROR;
+ goto out;
}
if (ret.eax & 0x1)
@@ -614,25 +614,21 @@ static acpi_status AMW0_set_capabilities
* But we need to kfree(out.pointer) if next wmab_execute fail.
*/
status = wmab_execute(&args, &out);
- if (ACPI_FAILURE(status)) {
- kfree(out.pointer);
- return status;
- }
+ if (ACPI_FAILURE(status))
+ goto out;
obj = (union acpi_object *) out.pointer;
if (obj && obj->type == ACPI_TYPE_BUFFER
&& obj->buffer.length == sizeof(struct wmab_ret)) {
ret = *((struct wmab_ret *) obj->buffer.pointer);
} else {
- kfree(out.pointer);
- return AE_ERROR;
+ status = AE_ERROR;
+ goto out;
}
if (ret.eax & 0x1)
interface->capability |= ACER_CAP_BLUETOOTH;
- kfree(out.pointer);
-
/*
* This appears to be safe to enable, since all Wistron based laptops
* appear to use the same EC register for brightness, even if they
@@ -641,7 +637,10 @@ static acpi_status AMW0_set_capabilities
if (quirks->brightness >= 0)
interface->capability |= ACER_CAP_BRIGHTNESS;
- return AE_OK;
+ status = AE_OK;
+out:
+ kfree(out.pointer);
+ return status;
}
static struct wmi_interface AMW0_interface = {
_
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] acer-wmi: fix memory leaks in wmab_execute error path
2010-07-13 1:35 ` Andrew Morton
@ 2010-07-13 2:14 ` Axel Lin
0 siblings, 0 replies; 4+ messages in thread
From: Axel Lin @ 2010-07-13 2:14 UTC (permalink / raw)
To: Andrew Morton
Cc: linux-kernel, Carlos Corbacho, Matthew Garrett, Thomas Renninger,
Alan Jenkins, platform-driver-x86
2010/7/13 Andrew Morton <akpm@linux-foundation.org>:
> On Fri, 09 Jul 2010 12:37:36 +0800 Axel Lin <axel.lin@gmail.com> wrote:
>
>> When acpi_evaluate_object() is passed ACPI_ALLOCATE_BUFFER,
>> the caller must kfree the returned buffer if AE_OK is returned.
>>
>> Call Trace:
>> wmab_execute
>> -> wmi_evaluate_method
>> -> acpi_evaluate_object
>>
>> Thus if callers of wmab_execute() pass ACPI_ALLOCATE_BUFFER,
>> the return buffer must be kfreed if wmab_execute return AE_OK.
>>
>> Signed-off-by: Axel Lin <axel.lin@gmail.com>
>> ---
>> drivers/platform/x86/acer-wmi.c | 11 ++++++++++-
>> 1 files changed, 10 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c
>> index 1ea6c43..3f44446 100644
>> --- a/drivers/platform/x86/acer-wmi.c
>> +++ b/drivers/platform/x86/acer-wmi.c
>> @@ -555,6 +555,7 @@ static acpi_status AMW0_find_mailled(void)
>> obj->buffer.length == sizeof(struct wmab_ret)) {
>> ret = *((struct wmab_ret *) obj->buffer.pointer);
>> } else {
>> + kfree(out.pointer);
>> return AE_ERROR;
>> }
>>
>> @@ -598,6 +599,7 @@ static acpi_status AMW0_set_capabilities(void)
>> obj->buffer.length == sizeof(struct wmab_ret)) {
>> ret = *((struct wmab_ret *) obj->buffer.pointer);
>> } else {
>> + kfree(out.pointer);
>> return AE_ERROR;
>> }
>>
>> @@ -607,15 +609,22 @@ static acpi_status AMW0_set_capabilities(void)
>> args.ebx = 2 << 8;
>> args.ebx |= ACER_AMW0_BLUETOOTH_MASK;
>>
>> + /*
>> + * It's ok to use existing buffer for next wmab_execute call.
>> + * But we need to kfree(out.pointer) if next wmab_execute fail.
>> + */
>> status = wmab_execute(&args, &out);
>> - if (ACPI_FAILURE(status))
>> + if (ACPI_FAILURE(status)) {
>> + kfree(out.pointer);
>> return status;
>> + }
>>
>> obj = (union acpi_object *) out.pointer;
>> if (obj && obj->type == ACPI_TYPE_BUFFER
>> && obj->buffer.length == sizeof(struct wmab_ret)) {
>> ret = *((struct wmab_ret *) obj->buffer.pointer);
>> } else {
>> + kfree(out.pointer);
>> return AE_ERROR;
>> }
>
> I think it's best to remove the multiple-return-points approach in
> favour of the "goto single return point which undoes things" approach.
> that way we reduce the risk of later introducing more leaks.
>
> Please review:
>
> From: Andrew Morton <akpm@linux-foundation.org>
>
> avoid multiple return points
> remove unneeded cast
> remove unneeded initialisation of `status'
>
> Cc: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
> Cc: Axel Lin <axel.lin@gmail.com>
> Cc: Carlos Corbacho <carlos@strangeworlds.co.uk>
> Cc: Matthew Garrett <mjg@redhat.com>
> Cc: Thomas Renninger <trenn@suse.de>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
I'm not the author, but since I'm in the CC list and it looks good to me.
Acked-by: Axel Lin <axel.lin@gmail.com>
> ---
>
> drivers/platform/x86/acer-wmi.c | 25 ++++++++++++-------------
> 1 file changed, 12 insertions(+), 13 deletions(-)
>
> diff -puN drivers/platform/x86/acer-wmi.c~acer-wmi-fix-memory-leaks-in-wmab_execute-error-path-v2-fix drivers/platform/x86/acer-wmi.c
> --- a/drivers/platform/x86/acer-wmi.c~acer-wmi-fix-memory-leaks-in-wmab_execute-error-path-v2-fix
> +++ a/drivers/platform/x86/acer-wmi.c
> @@ -571,7 +571,7 @@ static acpi_status AMW0_set_capabilities
> {
> struct wmab_args args;
> struct wmab_ret ret;
> - acpi_status status = AE_OK;
> + acpi_status status;
> struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
> union acpi_object *obj;
>
> @@ -594,13 +594,13 @@ static acpi_status AMW0_set_capabilities
> if (ACPI_FAILURE(status))
> return status;
>
> - obj = (union acpi_object *) out.pointer;
> + obj = out.pointer;
> if (obj && obj->type == ACPI_TYPE_BUFFER &&
> obj->buffer.length == sizeof(struct wmab_ret)) {
> ret = *((struct wmab_ret *) obj->buffer.pointer);
> } else {
> - kfree(out.pointer);
> - return AE_ERROR;
> + status = AE_ERROR;
> + goto out;
> }
>
> if (ret.eax & 0x1)
> @@ -614,25 +614,21 @@ static acpi_status AMW0_set_capabilities
> * But we need to kfree(out.pointer) if next wmab_execute fail.
> */
> status = wmab_execute(&args, &out);
> - if (ACPI_FAILURE(status)) {
> - kfree(out.pointer);
> - return status;
> - }
> + if (ACPI_FAILURE(status))
> + goto out;
>
> obj = (union acpi_object *) out.pointer;
> if (obj && obj->type == ACPI_TYPE_BUFFER
> && obj->buffer.length == sizeof(struct wmab_ret)) {
> ret = *((struct wmab_ret *) obj->buffer.pointer);
> } else {
> - kfree(out.pointer);
> - return AE_ERROR;
> + status = AE_ERROR;
> + goto out;
> }
>
> if (ret.eax & 0x1)
> interface->capability |= ACER_CAP_BLUETOOTH;
>
> - kfree(out.pointer);
> -
> /*
> * This appears to be safe to enable, since all Wistron based laptops
> * appear to use the same EC register for brightness, even if they
> @@ -641,7 +637,10 @@ static acpi_status AMW0_set_capabilities
> if (quirks->brightness >= 0)
> interface->capability |= ACER_CAP_BRIGHTNESS;
>
> - return AE_OK;
> + status = AE_OK;
> +out:
> + kfree(out.pointer);
> + return status;
> }
>
> static struct wmi_interface AMW0_interface = {
> _
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2010-07-13 2:15 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2010-07-09 4:37 [PATCH v2] acer-wmi: fix memory leaks in wmab_execute error path Axel Lin
2010-07-13 1:03 ` Axel Lin
2010-07-13 1:35 ` Andrew Morton
2010-07-13 2:14 ` Axel Lin
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