linux-kernel - [tip: x86/misc] x86/dumpstack: Don't mention RIP in "Code: "

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Date:   Tue, 20 Sep 2022 14:23:49 -0000
From:   "tip-bot2 for Jiri Slaby" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Jiri Slaby <jslaby@...e.cz>, Borislav Petkov <bp@...e.de>,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/misc] x86/dumpstack: Don't mention RIP in "Code: "

The following commit has been merged into the x86/misc branch of tip:

Commit-ID:     5258b80e60da6d8908ae2846b234ed8d9d9d4a19
Gitweb:        https://git.kernel.org/tip/5258b80e60da6d8908ae2846b234ed8d9d9d4a19
Author:        Jiri Slaby <jslaby@...e.cz>
AuthorDate:    Tue, 06 Sep 2022 09:11:23 +02:00
Committer:     Borislav Petkov <bp@...e.de>
CommitterDate: Tue, 20 Sep 2022 16:11:54 +02:00

x86/dumpstack: Don't mention RIP in "Code: "

Commit

  238c91115cd0 ("x86/dumpstack: Fix misleading instruction pointer error message")

changed the "Code:" line in bug reports when RIP is an invalid pointer.
In particular, the report currently says (for example):

  BUG: kernel NULL pointer dereference, address: 0000000000000000
  ...
  RIP: 0010:0x0
  Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.

That

  Unable to access opcode bytes at RIP 0xffffffffffffffd6.

is quite confusing as RIP value is 0, not -42. That -42 comes from
"regs->ip - PROLOGUE_SIZE", because Code is dumped with some prologue
(and epilogue).

So do not mention "RIP" on this line in this context.

Signed-off-by: Jiri Slaby <jslaby@...e.cz>
Signed-off-by: Borislav Petkov <bp@...e.de>
Link: https://lore.kernel.org/r/b772c39f-c5ae-8f17-fe6e-6a2bc4d1f83b@kernel.org
---
 arch/x86/kernel/dumpstack.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index afae4dd..b3dba35 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -128,7 +128,7 @@ void show_opcodes(struct pt_regs *regs, const char *loglvl)
 		/* No access to the user space stack of other tasks. Ignore. */
 		break;
 	default:
-		printk("%sCode: Unable to access opcode bytes at RIP 0x%lx.\n",
+		printk("%sCode: Unable to access opcode bytes at 0x%lx.\n",
 		       loglvl, prologue);
 		break;
 	}