From: Jiri Olsa <jolsa@redhat.com>
To: William Cohen <wcohen@redhat.com>
Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
linux-kernel@vger.kernel.org, alexander.shishkin@linux.intel.com,
namhyung@kernel.org
Subject: Re: [PATCH] Check jvmti_agent snprintf return value to avoid build failures with GCC-8.1.1
Date: Wed, 11 Jul 2018 00:58:24 +0200 [thread overview]
Message-ID: <20180710225824.GA11928@krava> (raw)
In-Reply-To: <20180710182716.21801-1-wcohen@redhat.com>
On Tue, Jul 10, 2018 at 02:27:16PM -0400, William Cohen wrote:
> Newer versions of GCC perform static analysis to determine whether
> string truncation is possible with functions such as snprintf and
> provide a warning if truncation could occur. The make for
> jvmti_agent.c uses the compiler option that treats any compiler
> warnings as compiler errors. For GCC-8.1.1 in Fedora 28 this causes
> the build to fail. The return value of the snprint is now checked to
> ensure snprintf produced a NULL-terminated string. If the string for
> the path is invalid, the code does attempt to use the string.
hi,
I posted fix for this recently:
https://lore.kernel.org/lkml/20180702134202.17745-1-jolsa@kernel.org/
it also covers the perf_regs.c, which was failing with gcc8 for me
should be pulled in soon
thanks,
jirka
>
> Signed-off-by: William Cohen <wcohen@redhat.com>
> ---
> tools/perf/jvmti/jvmti_agent.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/jvmti/jvmti_agent.c b/tools/perf/jvmti/jvmti_agent.c
> index 0c6d1002b524..30f14eafe4b3 100644
> --- a/tools/perf/jvmti/jvmti_agent.c
> +++ b/tools/perf/jvmti/jvmti_agent.c
> @@ -227,7 +227,7 @@ void *jvmti_open(void)
> {
> char dump_path[PATH_MAX];
> struct jitheader header;
> - int fd;
> + int retlen, fd;
> FILE *fp;
>
> init_arch_timestamp();
> @@ -249,7 +249,10 @@ void *jvmti_open(void)
> /*
> * jitdump file name
> */
> - snprintf(dump_path, PATH_MAX, "%s/jit-%i.dump", jit_path, getpid());
> + retlen = snprintf(dump_path, PATH_MAX, "%s/jit-%i.dump",
> + jit_path, getpid());
> + if (retlen <= 0 || ((int) sizeof(dump_path)) <= retlen)
> + return NULL;
>
> fd = open(dump_path, O_CREAT|O_TRUNC|O_RDWR, 0666);
> if (fd == -1)
> --
> 2.17.1
>
next prev parent reply other threads:[~2018-07-10 22:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-10 18:27 [PATCH] Check jvmti_agent snprintf return value to avoid build failures with GCC-8.1.1 William Cohen
2018-07-10 22:58 ` Jiri Olsa [this message]
2018-07-11 0:10 ` William Cohen
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