LinuxLists.cc - [RESEND PATCH] coresight: tmc: Explicit type conversions to prevent integer overflow

2023-07-14 09:01:05

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

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 <[email protected]>
---
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

2023-07-24 15:54:06

by James Clark

[permalink] [raw]

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

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/[email protected]/

Thanks
James

> Signed-off-by: Ruidong Tian <[email protected]>
> ---
> 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);

2023-08-02 12:39:02

by James Clark

[permalink] [raw]

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

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 <[email protected]>

>
> [1]:
> https://lore.kernel.org/bpf/[email protected]/
>
> 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/[email protected]/
>>
>> Thanks
>> James
>>
>>> Signed-off-by: Ruidong Tian <[email protected]>
>>> ---
>>> 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);

2023-08-02 13:12:44

by Ruidong Tian

[permalink] [raw]

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

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/[email protected]/

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/[email protected]/
>
> Thanks
> James
>
>> Signed-off-by: Ruidong Tian <[email protected]>
>> ---
>> 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);

2023-08-03 02:54:09

by Ruidong Tian

[permalink] [raw]

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

2023-08-03 16:45:52

by Suzuki K Poulose

[permalink] [raw]

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

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 <[email protected]>
> Reviewed-by: James Clark <[email protected]>

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

2023-08-04 03:27:56

by Ruidong Tian

[permalink] [raw]

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

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 <[email protected]>
>> Reviewed-by: James Clark <[email protected]>
>
> 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

2023-08-04 08:46:31

by Ruidong Tian

[permalink] [raw]

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

2023-08-04 09:26:14

by Ruidong Tian

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

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 <[email protected]>
Reviewed-by: James Clark <[email protected]>
---
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

2023-08-04 13:39:20

by Suzuki K Poulose

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

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 <[email protected]>
> Reviewed-by: James Clark <[email protected]>
> ---
> 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