From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: Date: Mon, 23 Jan 2023 12:09:26 +0100 MIME-Version: 1.0 To: Tvrtko Ursulin , igt-dev@lists.freedesktop.org, Intel-gfx@lists.freedesktop.org References: <20230119155428.3260937-1-tvrtko.ursulin@linux.intel.com> <46f7db49-eb5c-515f-b450-75cac53d770e@linux.intel.com> <3d3c7982-5ad3-d5a7-0574-ec1b9848dd2a@linux.intel.com> Content-Language: en-US From: "Das, Nirmoy" In-Reply-To: <3d3c7982-5ad3-d5a7-0574-ec1b9848dd2a@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [igt-dev] [Intel-gfx] [PATCH i-g-t] intel_gpu_top: Fix cleanup on old kernels / unsupported GPU List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: igt-dev-bounces@lists.freedesktop.org Sender: "igt-dev" List-ID: Hi Tvrtko, On 1/23/2023 11:24 AM, Tvrtko Ursulin wrote: > > On 20/01/2023 14:29, Das, Nirmoy wrote: >> Hi Tvrtko, >> >> On 1/19/2023 4:54 PM, Tvrtko Ursulin wrote: >>> From: Tvrtko Ursulin >>> >>> Avoid trying to dereference null engines on exit when there are either >>> none which are supported, or kernel does not have i915 PMU support. >>> >>> Signed-off-by: Tvrtko Ursulin >>> --- >>>   tools/intel_gpu_top.c | 10 +++++++--- >>>   1 file changed, 7 insertions(+), 3 deletions(-) >>> >>> diff --git a/tools/intel_gpu_top.c b/tools/intel_gpu_top.c >>> index 7aa233570463..517dc2995d26 100644 >>> --- a/tools/intel_gpu_top.c >>> +++ b/tools/intel_gpu_top.c >>> @@ -448,6 +448,9 @@ static void free_engines(struct engines *engines) >>>       }; >>>       unsigned int i; >>> +    if (!engines) >>> +        return; >>> + >> >> >> This check should happen before the  struct pmu_counter free_list >> generation. > > I could, but it doesn't have to, not sure what reasons for should you > have in mind? In my tree, I see: " static void free_engines(struct engines *engines) {         struct pmu_counter **pmu, *free_list[] = {                 &engines->r_gpu,                 &engines->r_pkg,                 &engines->imc_reads,                 &engines->imc_writes,                 NULL         };         unsigned int i; " Maybe I am missing something here, wouldn't those dereferences of "engines" segfault if the engines  is NULL. Regards, Nirmoy > > Regards, > > Tvrtko > >> >> Regards, >> >> Nirmoy >> >>>       for (pmu = &free_list[0]; *pmu; pmu++) { >>>           if ((*pmu)->present) >>>               free((char *)(*pmu)->units); >>> @@ -2568,7 +2571,7 @@ int main(int argc, char **argv) >>>               "Failed to detect engines! (%s)\n(Kernel 4.16 or newer >>> is required for i915 PMU support.)\n", >>>               strerror(errno)); >>>           ret = EXIT_FAILURE; >>> -        goto err; >>> +        goto err_engines; >>>       } >>>       ret = pmu_init(engines); >>> @@ -2585,7 +2588,7 @@ int main(int argc, char **argv) >>>   "More information can be found at 'Perf events and tool security' >>> document:\n" >>> "https://www.kernel.org/doc/html/latest/admin-guide/perf-security.html\n"); >>>           ret = EXIT_FAILURE; >>> -        goto err; >>> +        goto err_pmu; >>>       } >>>       ret = EXIT_SUCCESS; >>> @@ -2699,8 +2702,9 @@ int main(int argc, char **argv) >>>           free_clients(clients); >>>       free(codename); >>> -err: >>> +err_pmu: >>>       free_engines(engines); >>> +err_engines: >>>       free(pmu_device); >>>   exit: >>>       igt_devices_free();