linux-kernel - [RFC][PATCH 4/9] jump_label, x86: Improve error when we fail expected text

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Date:   Mon, 07 Oct 2019 10:44:47 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     x86@...nel.org
Cc:     peterz@...radead.org, linux-kernel@...r.kernel.org,
        rostedt@...dmis.org, mhiramat@...nel.org, bristot@...hat.com,
        jbaron@...mai.com, torvalds@...ux-foundation.org,
        tglx@...utronix.de, mingo@...nel.org, namit@...are.com,
        hpa@...or.com, luto@...nel.org, ard.biesheuvel@...aro.org,
        jpoimboe@...hat.com, hjl.tools@...il.com
Subject: [RFC][PATCH 4/9] jump_label, x86: Improve error when we fail expected text

There is only a single usage site left, remove the function and extend
the print to include more information, like the expected text and the
patch type.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/kernel/jump_label.c |   23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -16,17 +16,6 @@
 #include <asm/alternative.h>
 #include <asm/text-patching.h>
 
-static void bug_at(const void *ip, int line)
-{
-	/*
-	 * The location is not an op that we were expecting.
-	 * Something went wrong. Crash the box, as something could be
-	 * corrupting the kernel.
-	 */
-	pr_crit("jump_label: Fatal kernel bug, unexpected op at %pS [%p] (%5ph) %d\n", ip, ip, ip, line);
-	BUG();
-}
-
 static const void *
 __jump_label_set_jump_code(struct jump_entry *entry, enum jump_label_type type, int init)
 {
@@ -49,8 +38,16 @@ __jump_label_set_jump_code(struct jump_e
 		expect = code; line = __LINE__;
 	}
 
-	if (memcmp(addr, expect, JUMP_LABEL_NOP_SIZE))
-		bug_at(addr, line);
+	if (memcmp(addr, expect, JUMP_LABEL_NOP_SIZE)) {
+		/*
+		 * The location is not an op that we were expecting.
+		 * Something went wrong. Crash the box, as something could be
+		 * corrupting the kernel.
+		 */
+		pr_crit("jump_label: Fatal kernel bug, unexpected op at %pS [%p] (%5ph != %5ph)) line:%d init:%d type:%d\n",
+				addr, addr, addr, expect, line, init, type);
+		BUG();
+	}
 
 	if (type == JUMP_LABEL_NOP)
 		code = ideal_nop;