Commit 39fb393e authored Oct 03, 2021 by Song Liu Committed by Greg Kroah-Hartman Nov 02, 2021

perf script: Check session->header.env.arch before using it



commit 29c77550eef31b0d72a45b49eeab03b8963264e8 upstream.

When perf.data is not written cleanly, we would like to process existing
data as much as possible (please see f_header.data.size == 0 condition
in perf_session__read_header). However, perf.data with partial data may
crash perf. Specifically, we see crash in 'perf script' for NULL
session->header.env.arch.

Fix this by checking session->header.env.arch before using it to determine
native_arch. Also split the if condition so it is easier to read.

Committer notes:

If it is a pipe, we already assume is a native arch, so no need to check
session->header.env.arch.

Signed-off-by: Song Liu <songliubraving@fb.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@fb.com
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/20211004053238.514936-1-songliubraving@fb.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 472d9354

tools/perf/builtin-script.c

+8 −4

Original line number	Diff line number	Diff line
		@@ -3779,11 +3779,15 @@ int cmd_script(int argc, const char **argv)
		goto out_delete;

		uname(&uts);
		if (data.is_pipe \|\| /* assume pipe_mode indicates native_arch */
		!strcmp(uts.machine, session->header.env.arch) \|\|
		(!strcmp(uts.machine, "x86_64") &&
		!strcmp(session->header.env.arch, "i386")))
		if (data.is_pipe) { /* Assume pipe_mode indicates native_arch */
		native_arch = true;
		} else if (session->header.env.arch) {
		if (!strcmp(uts.machine, session->header.env.arch))
		native_arch = true;
		else if (!strcmp(uts.machine, "x86_64") &&
		!strcmp(session->header.env.arch, "i386"))
		native_arch = true;
		}

		script.session = session;
		script__setup_sample_type(&script);