[RESEND PATCH] coresight: tmc: Explicit type conversions to prevent integer overflow

[RESEND PATCH] coresight: tmc: Explicit type conversions to prevent integer overflow

[Ruidong Tian]

Perf cs_etm session will failed when AUX buffer > 1G.

  perf record -C 0 -m ,2G -e cs_etm// -- taskset -c 0 ls
  failed to mmap with 12 (Cannot allocate memory)

In coresight tmc driver, "nr_pages << PAGE_SHIFT" will overflow when
nr_pages >= 0x80000(correspond to 1G AUX buffer). Explicit convert nr_pages
to 64 bit to avoid overflow.

Signed-off-by: Ruidong Tian <tianruidong@linux.alibaba.com>
---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 2 +-
 drivers/hwtracing/coresight/coresight-tmc.h     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 766325de0e29..1425ecd1cf78 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1267,7 +1267,7 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event,
 	 * than the size requested via sysfs.
 	 */
 	if ((nr_pages << PAGE_SHIFT) > drvdata->size) {
-		etr_buf = tmc_alloc_etr_buf(drvdata, (nr_pages << PAGE_SHIFT),
+		etr_buf = tmc_alloc_etr_buf(drvdata, ((ssize_t)nr_pages << PAGE_SHIFT),
 					    0, node, NULL);
 		if (!IS_ERR(etr_buf))
 			goto done;
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index b97da39652d2..0ee48c5ba764 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -325,7 +325,7 @@ ssize_t tmc_sg_table_get_data(struct tmc_sg_table *sg_table,
 static inline unsigned long
 tmc_sg_table_buf_size(struct tmc_sg_table *sg_table)
 {
-	return sg_table->data_pages.nr_pages << PAGE_SHIFT;
+	return (unsigned long)sg_table->data_pages.nr_pages << PAGE_SHIFT;
 }
 
 struct coresight_device *tmc_etr_get_catu_device(struct tmc_drvdata *drvdata);
-- 
2.33.1


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Re: [RESEND PATCH] coresight: tmc: Explicit type conversions to prevent integer overflow

[Ruidong Tian]

Hi James,

Sorry, some local patch caused inaccurate information. Please allow me 
to reintroduce the question:

If you use perf with 1G AUX buffer, you can get 1G perf data. Perf 
workload is kernel build here:

     perf record -C 0 -m ,1G -e cs_etm// taskset -c 0 make

     [ perf record: Captured and wrote 1025.557 MB perf.data ]

But if you use 2G AUX buffer, perf was executed unexpectedly：

     perf record -C 0 -m ,2G -e cs_etm// taskset -c 0 make

     [ perf record: Captured and wrote 2.615 MB perf.data ]

There are just 2.615 MB perf data rather than 2G, if you probe function 
"tmc_alloc_etr_buf" in

coresight_tmc module, you can find some clues:

   perf probe -m coresight_tmc "tmc_alloc_etr_buf size:s64"

   perf record -e probe:tmc_alloc_etr_buf -aR -- perf record -C 0 -m ,2G 
-e cs_etm// -o cs.data taskset -c 0 make

   perf script
             perf 118267 [064]  4640.324670: probe:tmc_alloc_etr_buf: 
(ffff80007a9dce60) size_s64=-2147483648
             perf 118267 [064]  4640.324681: probe:tmc_alloc_etr_buf: 
(ffff80007a9dce60) size_s64=1048576

It's pretty obvious what's going on here. The first call of 
tmc_alloc_etr_buf in alloc_etr_buf was

failed because of overflow, the second call of tmc_alloc_etr_buf just 
alloc 1M AUX buffer which

is default ETR buffer size rather than 2G. That is why we can just get 
2.615MB ( 1M AUX data

+ perf header ).

It is necessary to check the conversion from int to s64 in coresight_tmc 
driver. The issue[1] also

exists in coresight/perf, but it's different from this topic.


[1]:
https://lore.kernel.org/bpf/20230711014120.53461-1-xueshuai@linux.alibaba.com/ 


Thanks
Ruidong

On 2023/7/24 23:38, James Clark wrote:
>
> On 14/07/2023 09:43, Ruidong Tian wrote:
>> Perf cs_etm session will failed when AUX buffer > 1G.
>>
>>    perf record -C 0 -m ,2G -e cs_etm// -- taskset -c 0 ls
>>    failed to mmap with 12 (Cannot allocate memory)
>>
>> In coresight tmc driver, "nr_pages << PAGE_SHIFT" will overflow when
>> nr_pages >= 0x80000(correspond to 1G AUX buffer). Explicit convert nr_pages
>> to 64 bit to avoid overflow.
>>
> Hi Ruidong,
>
> I couldn't reproduce this exact issue with the error message in the
> commit message. Is it not another manifestation related to this change
> [1]? I don't actually get any error message, but I was able to get a
> warning in dmesg even with [1] applied.
>
> Does the overflow not result in a successful session but with the wrong
> buffer size?
>
> I think the change makes sense, but maybe we also need a check for
> MAX_ORDER because I can trigger the same WARN_ON from [1]. Or maybe I'm
> a bit confused because of the other change and not being able to
> reproduce this exactly coming at the same time.
>
> [1]:
> https://lore.kernel.org/bpf/20230711014120.53461-1-xueshuai@linux.alibaba.com/
>
> Thanks
> James
>
>> Signed-off-by: Ruidong Tian <tianruidong@linux.alibaba.com>
>> ---
>>   drivers/hwtracing/coresight/coresight-tmc-etr.c | 2 +-
>>   drivers/hwtracing/coresight/coresight-tmc.h     | 2 +-
>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
>> index 766325de0e29..1425ecd1cf78 100644
>> --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
>> +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
>> @@ -1267,7 +1267,7 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event,
>>   	 * than the size requested via sysfs.
>>   	 */
>>   	if ((nr_pages << PAGE_SHIFT) > drvdata->size) {
>> -		etr_buf = tmc_alloc_etr_buf(drvdata, (nr_pages << PAGE_SHIFT),
>> +		etr_buf = tmc_alloc_etr_buf(drvdata, ((ssize_t)nr_pages << PAGE_SHIFT),
>>   					    0, node, NULL);
>>   		if (!IS_ERR(etr_buf))
>>   			goto done;
>> diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
>> index b97da39652d2..0ee48c5ba764 100644
>> --- a/drivers/hwtracing/coresight/coresight-tmc.h
>> +++ b/drivers/hwtracing/coresight/coresight-tmc.h
>> @@ -325,7 +325,7 @@ ssize_t tmc_sg_table_get_data(struct tmc_sg_table *sg_table,
>>   static inline unsigned long
>>   tmc_sg_table_buf_size(struct tmc_sg_table *sg_table)
>>   {
>> -	return sg_table->data_pages.nr_pages << PAGE_SHIFT;
>> +	return (unsigned long)sg_table->data_pages.nr_pages << PAGE_SHIFT;
>>   }
>>   
>>   struct coresight_device *tmc_etr_get_catu_device(struct tmc_drvdata *drvdata);

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Re: [RESEND PATCH] coresight: tmc: Explicit type conversions to prevent integer overflow

[James Clark]

On 02/08/2023 13:25, Ruidong Tian wrote:
> Hi James,
> 
> Sorry, some local patch caused inaccurate information. Please allow me
> to reintroduce the question:
> 
> If you use perf with 1G AUX buffer, you can get 1G perf data. Perf
> workload is kernel build here:
> 
>     perf record -C 0 -m ,1G -e cs_etm// taskset -c 0 make
> 
>     [ perf record: Captured and wrote 1025.557 MB perf.data ]
> 
> But if you use 2G AUX buffer, perf was executed unexpectedly：
> 
>     perf record -C 0 -m ,2G -e cs_etm// taskset -c 0 make
> 
>     [ perf record: Captured and wrote 2.615 MB perf.data ]
> 
> There are just 2.615 MB perf data rather than 2G, if you probe function
> "tmc_alloc_etr_buf" in
> 
> coresight_tmc module, you can find some clues:
> 
>   perf probe -m coresight_tmc "tmc_alloc_etr_buf size:s64"
> 
>   perf record -e probe:tmc_alloc_etr_buf -aR -- perf record -C 0 -m ,2G
> -e cs_etm// -o cs.data taskset -c 0 make
> 
>   perf script
>             perf 118267 [064]  4640.324670: probe:tmc_alloc_etr_buf:
> (ffff80007a9dce60) size_s64=-2147483648
>             perf 118267 [064]  4640.324681: probe:tmc_alloc_etr_buf:
> (ffff80007a9dce60) size_s64=1048576
> 
> It's pretty obvious what's going on here. The first call of
> tmc_alloc_etr_buf in alloc_etr_buf was
> 
> failed because of overflow, the second call of tmc_alloc_etr_buf just
> alloc 1M AUX buffer which
> 
> is default ETR buffer size rather than 2G. That is why we can just get
> 2.615MB ( 1M AUX data
> 
> + perf header ).
> 
> It is necessary to check the conversion from int to s64 in coresight_tmc
> driver. The issue[1] also
> 
> exists in coresight/perf, but it's different from this topic.
> 

Thanks for the investigation, that makes more sense to me now. Are you
able to send a v2 of the patch with an updated commit message describing
these symptoms instead?

And you can also add:

Reviewed-by: James Clark <james.clark@arm.com>

> 
> [1]:
> https://lore.kernel.org/bpf/20230711014120.53461-1-xueshuai@linux.alibaba.com/
> 
> Thanks
> Ruidong
> 
> On 2023/7/24 23:38, James Clark wrote:
>>
>> On 14/07/2023 09:43, Ruidong Tian wrote:
>>> Perf cs_etm session will failed when AUX buffer > 1G.
>>>
>>>    perf record -C 0 -m ,2G -e cs_etm// -- taskset -c 0 ls
>>>    failed to mmap with 12 (Cannot allocate memory)
>>>
>>> In coresight tmc driver, "nr_pages << PAGE_SHIFT" will overflow when
>>> nr_pages >= 0x80000(correspond to 1G AUX buffer). Explicit convert
>>> nr_pages
>>> to 64 bit to avoid overflow.
>>>
>> Hi Ruidong,
>>
>> I couldn't reproduce this exact issue with the error message in the
>> commit message. Is it not another manifestation related to this change
>> [1]? I don't actually get any error message, but I was able to get a
>> warning in dmesg even with [1] applied.
>>
>> Does the overflow not result in a successful session but with the wrong
>> buffer size?
>>
>> I think the change makes sense, but maybe we also need a check for
>> MAX_ORDER because I can trigger the same WARN_ON from [1]. Or maybe I'm
>> a bit confused because of the other change and not being able to
>> reproduce this exactly coming at the same time.
>>
>> [1]:
>> https://lore.kernel.org/bpf/20230711014120.53461-1-xueshuai@linux.alibaba.com/
>>
>> Thanks
>> James
>>
>>> Signed-off-by: Ruidong Tian <tianruidong@linux.alibaba.com>
>>> ---
>>>   drivers/hwtracing/coresight/coresight-tmc-etr.c | 2 +-
>>>   drivers/hwtracing/coresight/coresight-tmc.h     | 2 +-
>>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c
>>> b/drivers/hwtracing/coresight/coresight-tmc-etr.c
>>> index 766325de0e29..1425ecd1cf78 100644
>>> --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
>>> +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
>>> @@ -1267,7 +1267,7 @@ alloc_etr_buf(struct tmc_drvdata *drvdata,
>>> struct perf_event *event,
>>>        * than the size requested via sysfs.
>>>        */
>>>       if ((nr_pages << PAGE_SHIFT) > drvdata->size) {
>>> -        etr_buf = tmc_alloc_etr_buf(drvdata, (nr_pages << PAGE_SHIFT),
>>> +        etr_buf = tmc_alloc_etr_buf(drvdata, ((ssize_t)nr_pages <<
>>> PAGE_SHIFT),
>>>                           0, node, NULL);
>>>           if (!IS_ERR(etr_buf))
>>>               goto done;
>>> diff --git a/drivers/hwtracing/coresight/coresight-tmc.h
>>> b/drivers/hwtracing/coresight/coresight-tmc.h
>>> index b97da39652d2..0ee48c5ba764 100644
>>> --- a/drivers/hwtracing/coresight/coresight-tmc.h
>>> +++ b/drivers/hwtracing/coresight/coresight-tmc.h
>>> @@ -325,7 +325,7 @@ ssize_t tmc_sg_table_get_data(struct tmc_sg_table
>>> *sg_table,
>>>   static inline unsigned long
>>>   tmc_sg_table_buf_size(struct tmc_sg_table *sg_table)
>>>   {
>>> -    return sg_table->data_pages.nr_pages << PAGE_SHIFT;
>>> +    return (unsigned long)sg_table->data_pages.nr_pages << PAGE_SHIFT;
>>>   }
>>>     struct coresight_device *tmc_etr_get_catu_device(struct
>>> tmc_drvdata *drvdata);

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[PATCH v2] coresight: tmc: Explicit type conversions to prevent integer overflow

[Ruidong Tian]

Perf cs_etm session executed unexpectedly when AUX buffer > 1G.

  perf record -C 0 -m ,2G -e cs_etm// -- <workload>
  [ perf record: Captured and wrote 2.615 MB perf.data ]

Perf only collect about 2M perf data rather than 2G. This is becasuse
the operation, "nr_pages << PAGE_SHIFT", in coresight tmc driver, will
overflow when nr_pages >= 0x80000(correspond to 1G AUX buffer). The
overflow cause buffer allocation to fail, and TMC driver will alloc
minimal buffer size(1M). You can just get about 2M perf data(1M AUX
buffer + perf data header) at least.

Explicit convert nr_pages to 64 bit to avoid overflow.

Signed-off-by: Ruidong Tian <tianruidong@linux.alibaba.com>
Reviewed-by: James Clark <james.clark@arm.com>
---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 2 +-
 drivers/hwtracing/coresight/coresight-tmc.h     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 766325de0e29..1425ecd1cf78 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1267,7 +1267,7 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event,
 	 * than the size requested via sysfs.
 	 */
 	if ((nr_pages << PAGE_SHIFT) > drvdata->size) {
-		etr_buf = tmc_alloc_etr_buf(drvdata, (nr_pages << PAGE_SHIFT),
+		etr_buf = tmc_alloc_etr_buf(drvdata, ((ssize_t)nr_pages << PAGE_SHIFT),
 					    0, node, NULL);
 		if (!IS_ERR(etr_buf))
 			goto done;
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index b97da39652d2..0ee48c5ba764 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -325,7 +325,7 @@ ssize_t tmc_sg_table_get_data(struct tmc_sg_table *sg_table,
 static inline unsigned long
 tmc_sg_table_buf_size(struct tmc_sg_table *sg_table)
 {
-	return sg_table->data_pages.nr_pages << PAGE_SHIFT;
+	return (unsigned long)sg_table->data_pages.nr_pages << PAGE_SHIFT;
 }
 
 struct coresight_device *tmc_etr_get_catu_device(struct tmc_drvdata *drvdata);
-- 
2.33.1


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Re: [PATCH v2] coresight: tmc: Explicit type conversions to prevent integer overflow

[Suzuki K Poulose]

On 03/08/2023 03:33, Ruidong Tian wrote:
> Perf cs_etm session executed unexpectedly when AUX buffer > 1G.
> 
>    perf record -C 0 -m ,2G -e cs_etm// -- <workload>
>    [ perf record: Captured and wrote 2.615 MB perf.data ]
> 
> Perf only collect about 2M perf data rather than 2G. This is becasuse
> the operation, "nr_pages << PAGE_SHIFT", in coresight tmc driver, will
> overflow when nr_pages >= 0x80000(correspond to 1G AUX buffer). The
> overflow cause buffer allocation to fail, and TMC driver will alloc
> minimal buffer size(1M). You can just get about 2M perf data(1M AUX
> buffer + perf data header) at least.
> 
> Explicit convert nr_pages to 64 bit to avoid overflow.
> 
> Signed-off-by: Ruidong Tian <tianruidong@linux.alibaba.com>
> Reviewed-by: James Clark <james.clark@arm.com>

Fixes: 22f429f19c41 ("coresight: etm-perf: Add support for ETR backend")


> ---
>   drivers/hwtracing/coresight/coresight-tmc-etr.c | 2 +-
>   drivers/hwtracing/coresight/coresight-tmc.h     | 2 +-
>   2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
> index 766325de0e29..1425ecd1cf78 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
> @@ -1267,7 +1267,7 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event,
>   	 * than the size requested via sysfs.
>   	 */
>   	if ((nr_pages << PAGE_SHIFT) > drvdata->size) {
> -		etr_buf = tmc_alloc_etr_buf(drvdata, (nr_pages << PAGE_SHIFT),
> +		etr_buf = tmc_alloc_etr_buf(drvdata, ((ssize_t)nr_pages << PAGE_SHIFT),
>   					    0, node, NULL);
>   		if (!IS_ERR(etr_buf))
>   			goto done;
> diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
> index b97da39652d2..0ee48c5ba764 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc.h
> +++ b/drivers/hwtracing/coresight/coresight-tmc.h
> @@ -325,7 +325,7 @@ ssize_t tmc_sg_table_get_data(struct tmc_sg_table *sg_table,
>   static inline unsigned long
>   tmc_sg_table_buf_size(struct tmc_sg_table *sg_table)
>   {
> -	return sg_table->data_pages.nr_pages << PAGE_SHIFT;
> +	return (unsigned long)sg_table->data_pages.nr_pages << PAGE_SHIFT;
>   }
>   
>   struct coresight_device *tmc_etr_get_catu_device(struct tmc_drvdata *drvdata);

There are other places where such a fix is needed.
e.g.,

$ git grep "nr_pages << PAGE_SHIFT" 
drivers/hwtracing/coresight/coresight-tmc*
drivers/hwtracing/coresight/coresight-tmc-etf.c:        head = 
handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);
drivers/hwtracing/coresight/coresight-tmc-etr.c:#define 
PERF_IDX2OFF(idx, buf)  ((idx) % ((buf)->nr_pages << PAGE_SHIFT))
drivers/hwtracing/coresight/coresight-tmc-etr.c:        if ((nr_pages << 
PAGE_SHIFT) > drvdata->size) {
drivers/hwtracing/coresight/coresight-tmc-etr.c:                etr_buf 
= tmc_alloc_etr_buf(drvdata, (nr_pages << PAGE_SHIFT),
drivers/hwtracing/coresight/coresight-tmc.h:    return 
sg_table->data_pages.nr_pages << PAGE_SHIFT;

Are you able to fix all of them ?

Suzuki


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Re: [PATCH v2] coresight: tmc: Explicit type conversions to prevent integer overflow

[Ruidong Tian]

Sure, I will put them all to patch v3.

Ruidong

On 2023/8/4 00:19, Suzuki K Poulose wrote:
> On 03/08/2023 03:33, Ruidong Tian wrote:
>> Perf cs_etm session executed unexpectedly when AUX buffer > 1G.
>>
>>    perf record -C 0 -m ,2G -e cs_etm// -- <workload>
>>    [ perf record: Captured and wrote 2.615 MB perf.data ]
>>
>> Perf only collect about 2M perf data rather than 2G. This is becasuse
>> the operation, "nr_pages << PAGE_SHIFT", in coresight tmc driver, will
>> overflow when nr_pages >= 0x80000(correspond to 1G AUX buffer). The
>> overflow cause buffer allocation to fail, and TMC driver will alloc
>> minimal buffer size(1M). You can just get about 2M perf data(1M AUX
>> buffer + perf data header) at least.
>>
>> Explicit convert nr_pages to 64 bit to avoid overflow.
>>
>> Signed-off-by: Ruidong Tian <tianruidong@linux.alibaba.com>
>> Reviewed-by: James Clark <james.clark@arm.com>
>
> Fixes: 22f429f19c41 ("coresight: etm-perf: Add support for ETR backend")
>
>
>> ---
>>   drivers/hwtracing/coresight/coresight-tmc-etr.c | 2 +-
>>   drivers/hwtracing/coresight/coresight-tmc.h     | 2 +-
>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c 
>> b/drivers/hwtracing/coresight/coresight-tmc-etr.c
>> index 766325de0e29..1425ecd1cf78 100644
>> --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
>> +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
>> @@ -1267,7 +1267,7 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, 
>> struct perf_event *event,
>>        * than the size requested via sysfs.
>>        */
>>       if ((nr_pages << PAGE_SHIFT) > drvdata->size) {
>> -        etr_buf = tmc_alloc_etr_buf(drvdata, (nr_pages << PAGE_SHIFT),
>> +        etr_buf = tmc_alloc_etr_buf(drvdata, ((ssize_t)nr_pages << 
>> PAGE_SHIFT),
>>                           0, node, NULL);
>>           if (!IS_ERR(etr_buf))
>>               goto done;
>> diff --git a/drivers/hwtracing/coresight/coresight-tmc.h 
>> b/drivers/hwtracing/coresight/coresight-tmc.h
>> index b97da39652d2..0ee48c5ba764 100644
>> --- a/drivers/hwtracing/coresight/coresight-tmc.h
>> +++ b/drivers/hwtracing/coresight/coresight-tmc.h
>> @@ -325,7 +325,7 @@ ssize_t tmc_sg_table_get_data(struct tmc_sg_table 
>> *sg_table,
>>   static inline unsigned long
>>   tmc_sg_table_buf_size(struct tmc_sg_table *sg_table)
>>   {
>> -    return sg_table->data_pages.nr_pages << PAGE_SHIFT;
>> +    return (unsigned long)sg_table->data_pages.nr_pages << PAGE_SHIFT;
>>   }
>>     struct coresight_device *tmc_etr_get_catu_device(struct 
>> tmc_drvdata *drvdata);
>
> There are other places where such a fix is needed.
> e.g.,
>
> $ git grep "nr_pages << PAGE_SHIFT" 
> drivers/hwtracing/coresight/coresight-tmc*
> drivers/hwtracing/coresight/coresight-tmc-etf.c:        head = 
> handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);
> drivers/hwtracing/coresight/coresight-tmc-etr.c:#define 
> PERF_IDX2OFF(idx, buf)  ((idx) % ((buf)->nr_pages << PAGE_SHIFT))
> drivers/hwtracing/coresight/coresight-tmc-etr.c:        if ((nr_pages 
> << PAGE_SHIFT) > drvdata->size) {
> drivers/hwtracing/coresight/coresight-tmc-etr.c: etr_buf = 
> tmc_alloc_etr_buf(drvdata, (nr_pages << PAGE_SHIFT),
> drivers/hwtracing/coresight/coresight-tmc.h:    return 
> sg_table->data_pages.nr_pages << PAGE_SHIFT;
>
> Are you able to fix all of them ?
>
> Suzuki

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[PATCH v3 0/1] coresight: tmc: Explicit type conversions to

[Ruidong Tian]

Perf cs_etm session executed unexpectedly when AUX buffer > 1G.

  perf record -C 0 -m ,2G -e cs_etm// -- <workload>
  [ perf record: Captured and wrote 2.615 MB perf.data ]

Perf only collect about 2M perf data rather than 2G. This is becasuse
the operation, "nr_pages << PAGE_SHIFT", in coresight tmc driver, will
overflow when nr_pages >= 0x80000(correspond to 1G AUX buffer). The
overflow cause buffer allocation to fail, and TMC driver will alloc
minimal buffer size(1M). You can just get about 2M perf data(1M AUX
buffer + perf data header) at least.

Explicit convert nr_pages to 64 bit in tmc driver to avoid overflow.

Changes in V2:
Suzuki K Poulose:
    Add another 2 places where needed to fix.

Changes in V1:
James Clark:
    Use a more accurate commit message.

Ruidong Tian (1):
  coresight: tmc: Explicit type conversions to prevent integer overflow

 drivers/hwtracing/coresight/coresight-tmc-etf.c | 2 +-
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 5 +++--
 drivers/hwtracing/coresight/coresight-tmc.h     | 2 +-
 3 files changed, 5 insertions(+), 4 deletions(-)

-- 
2.33.1


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[PATCH v3 1/1] coresight: tmc: Explicit type conversions to prevent integer overflow

[Ruidong Tian]

Perf cs_etm session executed unexpectedly when AUX buffer > 1G.

  perf record -C 0 -m ,2G -e cs_etm// -- <workload>
  [ perf record: Captured and wrote 2.615 MB perf.data ]

Perf only collect about 2M perf data rather than 2G. This is becasuse
the operation, "nr_pages << PAGE_SHIFT", in coresight tmc driver, will
overflow when nr_pages >= 0x80000(correspond to 1G AUX buffer). The
overflow cause buffer allocation to fail, and TMC driver will alloc
minimal buffer size(1M). You can just get about 2M perf data(1M AUX
buffer + perf data header) at least.

Explicit convert nr_pages to 64 bit to avoid overflow.

Fixes: 22f429f19c41 ("coresight: etm-perf: Add support for ETR backend")
Signed-off-by: Ruidong Tian <tianruidong@linux.alibaba.com>
Reviewed-by: James Clark <james.clark@arm.com>
---
 drivers/hwtracing/coresight/coresight-tmc-etf.c | 2 +-
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 5 +++--
 drivers/hwtracing/coresight/coresight-tmc.h     | 2 +-
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 79d8c64eac49..7406b65e2cdd 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -452,7 +452,7 @@ static int tmc_set_etf_buffer(struct coresight_device *csdev,
 		return -EINVAL;
 
 	/* wrap head around to the amount of space we have */
-	head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);
+	head = handle->head & (((unsigned long)buf->nr_pages << PAGE_SHIFT) - 1);
 
 	/* find the page to write to */
 	buf->cur = head / PAGE_SIZE;
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 766325de0e29..66dc5f97a009 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -45,7 +45,8 @@ struct etr_perf_buffer {
 };
 
 /* Convert the perf index to an offset within the ETR buffer */
-#define PERF_IDX2OFF(idx, buf)	((idx) % ((buf)->nr_pages << PAGE_SHIFT))
+#define PERF_IDX2OFF(idx, buf)		\
+		((idx) % ((unsigned long)(buf)->nr_pages << PAGE_SHIFT))
 
 /* Lower limit for ETR hardware buffer */
 #define TMC_ETR_PERF_MIN_BUF_SIZE	SZ_1M
@@ -1267,7 +1268,7 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event,
 	 * than the size requested via sysfs.
 	 */
 	if ((nr_pages << PAGE_SHIFT) > drvdata->size) {
-		etr_buf = tmc_alloc_etr_buf(drvdata, (nr_pages << PAGE_SHIFT),
+		etr_buf = tmc_alloc_etr_buf(drvdata, ((ssize_t)nr_pages << PAGE_SHIFT),
 					    0, node, NULL);
 		if (!IS_ERR(etr_buf))
 			goto done;
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index b97da39652d2..0ee48c5ba764 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -325,7 +325,7 @@ ssize_t tmc_sg_table_get_data(struct tmc_sg_table *sg_table,
 static inline unsigned long
 tmc_sg_table_buf_size(struct tmc_sg_table *sg_table)
 {
-	return sg_table->data_pages.nr_pages << PAGE_SHIFT;
+	return (unsigned long)sg_table->data_pages.nr_pages << PAGE_SHIFT;
 }
 
 struct coresight_device *tmc_etr_get_catu_device(struct tmc_drvdata *drvdata);
-- 
2.33.1


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Re: [PATCH v3 1/1] coresight: tmc: Explicit type conversions to prevent integer overflow

[Suzuki K Poulose]

On 04/08/2023 09:15, Ruidong Tian wrote:
> Perf cs_etm session executed unexpectedly when AUX buffer > 1G.
> 
>    perf record -C 0 -m ,2G -e cs_etm// -- <workload>
>    [ perf record: Captured and wrote 2.615 MB perf.data ]
> 
> Perf only collect about 2M perf data rather than 2G. This is becasuse
> the operation, "nr_pages << PAGE_SHIFT", in coresight tmc driver, will
> overflow when nr_pages >= 0x80000(correspond to 1G AUX buffer). The
> overflow cause buffer allocation to fail, and TMC driver will alloc
> minimal buffer size(1M). You can just get about 2M perf data(1M AUX
> buffer + perf data header) at least.
> 
> Explicit convert nr_pages to 64 bit to avoid overflow.
> 
> Fixes: 22f429f19c41 ("coresight: etm-perf: Add support for ETR backend")
> Signed-off-by: Ruidong Tian <tianruidong@linux.alibaba.com>
> Reviewed-by: James Clark <james.clark@arm.com>
> ---
>   drivers/hwtracing/coresight/coresight-tmc-etf.c | 2 +-
>   drivers/hwtracing/coresight/coresight-tmc-etr.c | 5 +++--
>   drivers/hwtracing/coresight/coresight-tmc.h     | 2 +-
>   3 files changed, 5 insertions(+), 4 deletions(-)


Added additional Fixes tags as required and pushed it here :

https://git.kernel.org/coresight/c/fd380097cdb3

Thanks!
Suzuki

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