linux-kernel - [PATCH 3/3] lib: dump_stack: explicitly pass current to show

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Date:   Mon, 26 Sep 2016 16:16:19 +0100
From:   Mark Rutland <mark.rutland@....com>
To:     linux-kernel@...r.kernel.org
Cc:     Mark Rutland <mark.rutland@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Eric Dumazet <edumazet@...gle.com>,
        Ingo Molnar <mingo@...nel.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>
Subject: [PATCH 3/3] lib: dump_stack: explicitly pass current to show_stack

As noted in commit:

  81539169f283329f ("x86/dumpstack: Remove NULL task pointer convention")

... having a NULL task parameter imply current leads to subtle bugs in stack
walking code (so far seen on both 86 and arm64), makes callsites harder to
read, and is unnecessary as all callers have access to current.

As a step towards removing the problematic NULL-implies-current idiom entirely,
have the dump_stack code explicitly pass current to show_stack.

Signed-off-by: Mark Rutland <mark.rutland@....com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Eric Dumazet <edumazet@...gle.com>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: linux-kernel@...r.kernel.org
---
 lib/dump_stack.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index c30d07e..7296b63 100644
--- a/lib/dump_stack.c
+++ b/lib/dump_stack.c
@@ -12,7 +12,7 @@
 static void __dump_stack(void)
 {
 	dump_stack_print_info(KERN_DEFAULT);
-	show_stack(NULL, NULL);
+	show_stack(current, NULL);
 }
 
 /**
-- 
2.7.4