Before disassembling, the tool objdump is called just to be sure:
* objdump is available in the path;
* objdump is an executable binary;
* objdump has no dependency issue or anything else.

This objdump "pre-"command is only necessary because the real objdump
command is followed by some " | grep ..."; this prevents the shell
from returning the exit code of objdump execution.

Signed-off-by: Alexis Berlemont <alexis.berlem...@gmail.com>
---
 tools/perf/util/annotate.c | 79 +++++++++++++++++++++++++++++++++++++++++++++-
 tools/perf/util/annotate.h |  3 ++
 2 files changed, 81 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 3e34ee0..9d6c3a0 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -20,9 +20,12 @@
 #include "block-range.h"
 #include "arch/common.h"
 #include <regex.h>
+#include <unistd.h>
 #include <pthread.h>
 #include <linux/bitops.h>
 #include <sys/utsname.h>
+#include <sys/types.h>
+#include <sys/wait.h>
 
 const char     *disassembler_style;
 const char     *objdump_path;
@@ -1278,6 +1281,21 @@ int symbol__strerror_disassemble(struct symbol *sym 
__maybe_unused, struct map *
                          "  --vmlinux vmlinux\n", build_id_msg ?: "");
        }
                break;
+
+       case SYMBOL_ANNOTATE_ERRNO__NO_OBJDUMP:
+               scnprintf(buf, buflen, "No objdump tool available in $PATH\n");
+               break;
+
+       case SYMBOL_ANNOTATE_ERRNO__NO_EXEC_OBJDUMP:
+               scnprintf(buf, buflen,
+                       "The objdump tool found in $PATH cannot be executed\n");
+               break;
+
+       case SYMBOL_ANNOTATE_ERRNO__NO_OUTPUT:
+               scnprintf(buf, buflen,
+                       "The objdump tool returned no disassembled code\n");
+               break;
+
        default:
                scnprintf(buf, buflen, "Internal error: Invalid %d error 
code\n", errnum);
                break;
@@ -1321,6 +1339,61 @@ static int dso__disassemble_filename(struct dso *dso, 
char *filename, size_t fil
        return 0;
 }
 
+static int annotate__check_objdump(void)
+{
+       char command[PATH_MAX * 2];
+       int wstatus, err;
+       pid_t pid;
+
+       snprintf(command, sizeof(command),
+               "%s -v > /dev/null 2>&1",
+               objdump_path ? objdump_path : "objdump");
+
+       pid = fork();
+       if (pid < 0) {
+               pr_err("Failure forking to run %s\n", command);
+               return -1;
+       }
+
+       if (pid == 0) {
+               execl("/bin/sh", "sh", "-c", command, NULL);
+               exit(-1);
+       }
+
+       err = waitpid(pid, &wstatus, 0);
+       if (err < 0) {
+               pr_err("Failure calling waitpid: %s: (%s)\n",
+                       strerror(errno), command);
+               return -1;
+       }
+
+       pr_err("%s: %d %d\n", command, pid, WEXITSTATUS(wstatus));
+
+       switch (WEXITSTATUS(wstatus)) {
+       case 0:
+               /* Success */
+               err = 0;
+               break;
+       case 127:
+               /* The shell did not find objdump in the path */
+               err = SYMBOL_ANNOTATE_ERRNO__NO_OBJDUMP;
+               break;
+       default:
+               /*
+                * In the default case, we consider that objdump
+                * cannot be executed; so it gathers many fault
+                * scenarii:
+                * - objdump is not an executable (126);
+                * - objdump has some dependency issue;
+                * - ...
+                */
+               err = SYMBOL_ANNOTATE_ERRNO__NO_EXEC_OBJDUMP;
+               break;
+       }
+
+       return err;
+}
+
 static const char *annotate__norm_arch(const char *arch_name)
 {
        struct utsname uts;
@@ -1351,6 +1424,10 @@ int symbol__disassemble(struct symbol *sym, struct map 
*map, const char *arch_na
        if (err)
                return err;
 
+       err = annotate__check_objdump();
+       if (err)
+               return err;
+
        arch_name = annotate__norm_arch(arch_name);
        if (!arch_name)
                return -1;
@@ -1482,7 +1559,7 @@ int symbol__disassemble(struct symbol *sym, struct map 
*map, const char *arch_na
                delete_last_nop(sym);
 
        fclose(file);
-       err = 0;
+       err = nline == 0 ? SYMBOL_ANNOTATE_ERRNO__NO_OUTPUT : 0;
 out_remove_tmp:
        close(stdout_fd[0]);
 
diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
index 87e4cad..123f60c 100644
--- a/tools/perf/util/annotate.h
+++ b/tools/perf/util/annotate.h
@@ -172,6 +172,9 @@ enum symbol_disassemble_errno {
        __SYMBOL_ANNOTATE_ERRNO__START          = -10000,
 
        SYMBOL_ANNOTATE_ERRNO__NO_VMLINUX       = 
__SYMBOL_ANNOTATE_ERRNO__START,
+       SYMBOL_ANNOTATE_ERRNO__NO_EXEC_OBJDUMP,
+       SYMBOL_ANNOTATE_ERRNO__NO_OBJDUMP,
+       SYMBOL_ANNOTATE_ERRNO__NO_OUTPUT,
 
        __SYMBOL_ANNOTATE_ERRNO__END,
 };
-- 
2.10.2

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