objtool: Move objtool_file struct off the stack

jpoimboe · KAGA-KOKO · commit 0c671812f152 · 2019-03-21T12:02:19.000+01:00
Objtool uses over 512k of stack, thanks to the hash table embedded in the objtool_file struct. This causes an unnecessarily large stack allocation and breaks users with low stack limits. Move the struct off the stack. Fixes: 042ba73 ("objtool: Add several performance improvements") Reported-by: Vassili Karpov <moosotc@gmail.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/df92dcbc4b84b02ffa252f46876df125fb56e2d7.1552954176.git.jpoimboe@redhat.com
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
@@ -2184,9 +2184,10 @@ static void cleanup(struct objtool_file *file)
 	elf_close(file->elf);
 }
 
+static struct objtool_file file;
+
 int check(const char *_objname, bool orc)
 {
-	struct objtool_file file;
 	int ret, warnings = 0;
 
 	objname = _objname;

Original file line number	Diff line number	Diff line change
`@@ -2184,9 +2184,10 @@ static void cleanup(struct objtool_file *file)`
`2184`	`2184`	`elf_close(file->elf);`
`2185`	`2185`	`}`
`2186`	`2186`
	`2187`	`+static struct objtool_file file;`
	`2188`	`+`
`2187`	`2189`	`int check(const char *_objname, bool orc)`
`2188`	`2190`	`{`
`2189`		`- struct objtool_file file;`
`2190`	`2191`	`int ret, warnings = 0;`
`2191`	`2192`
`2192`	`2193`	`objname = _objname;`