Hi,
On Wed, 2 Apr 2025 at 01:50, Jie Gan quic_jiegan@quicinc.com wrote:
On 4/1/2025 5:56 PM, Mike Leach wrote:
Hi,
On Tue, 1 Apr 2025 at 07:11, Anshuman Khandual anshuman.khandual@arm.com wrote:
On 4/1/25 07:12, Jie Gan wrote:
The trace_id in coresight_path may contain an error number which means a negative integer, but the current type of the trace_id is u8. Change the type to int to fix it.
Reported-by: Dan Carpenter dan.carpenter@linaro.org Fixes: 3c03c49b2fa5 ("Coresight: Introduce a new struct coresight_path") Signed-off-by: Jie Gan jie.gan@oss.qualcomm.com
LGTM
Reviewed-by: Anshuman Khandual anshuman.khandual@arm.com
include/linux/coresight.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/coresight.h b/include/linux/coresight.h index d79a242b271d..c2bf10c43e7c 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -337,7 +337,7 @@ static struct coresight_dev_list (var) = { \ */ struct coresight_path { struct list_head path_list;
u8 trace_id;
int trace_id;};
enum cs_mode {
There are many places in the Coresight drivers that assign a u8 traceid from the path trace ID.
e.g. In coresight-etm4x-core.c : etm4_enable_perf()
drvdata->trcid = path->trace_id;
drvdata->trcid is defined as a u8 - the reason being trace IDs are 128 bits wide with some reserved values.
Will this not just trigger the same issue if path->trace_id is changed to an int? Even if not it is inconsistent handling of the trace ID values.
Trace ID errors should be handled by returning an invalid trace ID value - were the trace ID value will fail the macro IS_VALID_CS_TRACE_ID(), or separate the return of a trace ID from an error return in a function.
Hi Mike,
The path->trace_id is verified after it has been assigned with the logic you mentioned:
if (!IS_VALID_CS_TRACE_ID(path->trace_id)) goto err_path;
So it should be safe to assign to another u8 parameter, like you mentioned:
In coresight-etm4x-core.c : etm4_enable_perf()
drvdata->trcid = path->trace_id;
It is safe but will it not trigger a warning just like the one you are trying to fix as the types are mismatched?
Mike
Thanks, Jie
Regards
Mike
-- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK
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Mike Leach