From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Kim Phillips <kim.phillips@amd.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Ian Rogers <irogers@google.com>, Ingo Molnar <mingo@redhat.com>,
Jiri Olsa <jolsa@redhat.com>,
Joao Martins <joao.m.martins@oracle.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Mark Rutland <mark.rutland@arm.com>,
Michael Petlan <mpetlan@redhat.com>,
Namhyung Kim <namhyung@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Robert Richter <robert.richter@amd.com>,
Stephane Eranian <eranian@google.com>,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Subject: Re: [PATCH 0/3] perf report: Add support to print a textual representation of IBS raw sample data
Date: Fri, 10 Sep 2021 11:17:11 -0300 [thread overview]
Message-ID: <YTto5xw/XSMuiGrG@kernel.org> (raw)
In-Reply-To: <YTtnpAcaCNYozoJF@kernel.org>
Em Fri, Sep 10, 2021 at 11:11:48AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Fri, Sep 10, 2021 at 11:08:02AM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Fri, Sep 10, 2021 at 10:47:16AM -0300, Arnaldo Carvalho de Melo escreveu:
> > > Em Thu, Sep 09, 2021 at 04:58:12PM -0500, Kim Phillips escreveu:
> > > > Hi Arnaldo,
> > > >
> > > > Can you please take a look at applying this series? Its kernel-side
> > > > dependent series has already been applied and is in Linus' master.
> > >
> > > Sure, I'm now trying to fix this:
> > >
> > > CC /tmp/build/perf/util/amd-sample-raw.o
> > > util/amd-sample-raw.c: In function ‘evlist__amd_sample_raw’:
> > > util/amd-sample-raw.c:125:42: error: ‘ bytes’ directive output may be truncated writing 6 bytes into a region of size between 4 and 7 [-Werror=format-truncation=]
> > > 125 | " OpMemWidth %2d bytes", 1 << (reg.op_mem_width - 1));
> > > | ^~~~~~
> > > In file included from /usr/include/stdio.h:866,
> > > from util/amd-sample-raw.c:7:
> > > /usr/include/bits/stdio2.h:71:10: note: ‘__builtin___snprintf_chk’ output between 21 and 24 bytes into a destination of size 21
> > > 71 | return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
> > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > 72 | __glibc_objsize (__s), __fmt,
> > > | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > 73 | __va_arg_pack ());
> > > | ~~~~~~~~~~~~~~~~~
> > > cc1: all warnings being treated as errors
> > > make[4]: *** [/var/home/acme/git/perf/tools/build/Makefile.build:96: /tmp/build/perf/util/amd-sample-raw.o] Error 1
> >
> > So, that trick with using sizeof and that string 3 times is cumbersome
> > and prone to truncation, at least the compiler can't say that the number
> > you're passing to %2d will have just 2 digits:
> >
> > [acme@quaco c]$ cat printf.c
> > #include <stdio.h>
> > #include <stdlib.h>
> >
> > int main(int argc, char *argv[])
> > {
> > char bf[64];
> > int len = snprintf(bf, sizeof(bf), "%2d", atoi(argv[1]));
> >
> > printf("strlen(%s): %u\n", bf, len);
> >
> > return 0;
> > }
> > [acme@quaco c]$ ./printf 1234567
> > strlen(1234567): 7
> > [acme@quaco c]$
> >
> > I'm trying to rework this.
>
> So below is the minimal fix, the other cases the compiler somehow thinks
> its ok, so I'll keep as is, will just remove the sizeof(string) to
> sizeof(var), as I did below for the offending case.
End result:
diff --git a/tools/perf/util/amd-sample-raw.c b/tools/perf/util/amd-sample-raw.c
index fc1f670e88562b2e..fbb7d61c50489374 100644
--- a/tools/perf/util/amd-sample-raw.c
+++ b/tools/perf/util/amd-sample-raw.c
@@ -106,7 +106,7 @@ static void pr_ibs_op_data2(union ibs_op_data2 reg)
static void pr_ibs_op_data3(union ibs_op_data3 reg)
{
char l2_miss_str[sizeof(" L2Miss _")] = "";
- char op_mem_width_str[sizeof(" OpMemWidth __ bytes")] = "";
+ char op_mem_width_str[sizeof(" OpMemWidth _____ bytes")] = "";
char op_dc_miss_open_mem_reqs_str[sizeof(" OpDcMissOpenMemReqs __")] = "";
/*
@@ -114,14 +114,13 @@ static void pr_ibs_op_data3(union ibs_op_data3 reg)
* Ignore L2Miss and OpDcMissOpenMemReqs (and opdata2) if DcMissNoMabAlloc or SwPf set
*/
if (!(cpu_family == 0x19 && cpu_model < 0x10 && (reg.dc_miss_no_mab_alloc || reg.sw_pf))) {
- snprintf(l2_miss_str, sizeof(" L2Miss _"),
- " L2Miss %d", reg.l2_miss);
- snprintf(op_dc_miss_open_mem_reqs_str, sizeof(" OpDcMissOpenMemReqs __"),
+ snprintf(l2_miss_str, sizeof(l2_miss_str), " L2Miss %d", reg.l2_miss);
+ snprintf(op_dc_miss_open_mem_reqs_str, sizeof(op_dc_miss_open_mem_reqs_str),
" OpDcMissOpenMemReqs %2d", reg.op_dc_miss_open_mem_reqs);
}
if (reg.op_mem_width)
- snprintf(op_mem_width_str, sizeof(" OpMemWidth __ bytes"),
+ snprintf(op_mem_width_str, sizeof(op_mem_width_str),
" OpMemWidth %2d bytes", 1 << (reg.op_mem_width - 1));
printf("ibs_op_data3:\t%016llx LdOp %d StOp %d DcL1TlbMiss %d DcL2TlbMiss %d "
next prev parent reply other threads:[~2021-09-10 14:17 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-17 22:15 [PATCH 0/3] perf report: Add support to print a textual representation of IBS raw sample data Kim Phillips
2021-08-17 22:15 ` [PATCH 1/3] perf env: Add perf_env__cpuid, perf_env__{nr_}pmu_mappings Kim Phillips
2021-08-17 22:15 ` [PATCH 2/3] perf report: Add tools/arch/x86/include/asm/amd-ibs.h Kim Phillips
2021-08-17 22:15 ` [PATCH 3/3] perf report: Add support to print a textual representation of IBS raw sample data Kim Phillips
2021-09-09 21:58 ` [PATCH 0/3] " Kim Phillips
2021-09-10 13:47 ` Arnaldo Carvalho de Melo
2021-09-10 14:08 ` Arnaldo Carvalho de Melo
2021-09-10 14:11 ` Arnaldo Carvalho de Melo
2021-09-10 14:17 ` Arnaldo Carvalho de Melo [this message]
2021-09-10 19:48 ` Another bug: " Arnaldo Carvalho de Melo
2021-09-10 20:58 ` Arnaldo Carvalho de Melo
2021-09-10 21:40 ` Arnaldo Carvalho de Melo
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