Commit 5d12f042 authored by Borislav Petkov's avatar Borislav Petkov Committed by Thomas Gleixner
Browse files

x86/dumpstack: Remove code_bytes 



This was added by

  86c41837 ("[PATCH] i386: add option to show more code in oops reports")

long time ago but experience shows that 64 instruction bytes are plenty
when deciphering an oops. So get rid of it.

Removing it will simplify further enhancements to the opcodes dumping
machinery coming in the following patches.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Link: https://lkml.kernel.org/r/20180417161124.5294-2-bp@alien8.de
parent 6d08b06e

Documentation/admin-guide/kernel-parameters.txt

+0 −5
Original line number Diff line number Diff line
@@ -587,11 +587,6 @@ 
			Sets the size of memory pool for coherent, atomic dma

			allocations, by default set to 256K.



	code_bytes	[X86] How many bytes of object code to print

			in an oops report.

			Range: 0 - 8192

			Default: 64



	com20020=	[HW,NET] ARCnet - COM20020 chipset

			Format:

			<io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]

arch/x86/kernel/dumpstack.c

+4 −23
Original line number Diff line number Diff line
@@ -22,9 +22,10 @@ 
#include <asm/stacktrace.h>

#include <asm/unwind.h>



#define OPCODE_BUFSIZE 64



int panic_on_unrecovered_nmi;

int panic_on_io_nmi;

static unsigned int code_bytes = 64;

static int die_counter;



bool in_task_stack(unsigned long *stack, struct task_struct *task,
@@ -356,26 +357,6 @@ void die(const char *str, struct pt_regs *regs, long err) 
	oops_end(flags, regs, sig);

}



static int __init code_bytes_setup(char *s)

{

	ssize_t ret;

	unsigned long val;



	if (!s)

		return -EINVAL;



	ret = kstrtoul(s, 0, &val);

	if (ret)

		return ret;



	code_bytes = val;

	if (code_bytes > 8192)

		code_bytes = 8192;



	return 1;

}

__setup("code_bytes=", code_bytes_setup);



void show_regs(struct pt_regs *regs)

{

	bool all = true;
@@ -393,8 +374,8 @@ void show_regs(struct pt_regs *regs) 
	 * time of the fault..

	 */

	if (!user_mode(regs)) {

		unsigned int code_prologue = code_bytes * 43 / 64;

		unsigned int code_len = code_bytes;

		unsigned int code_prologue = OPCODE_BUFSIZE * 43 / 64;

		unsigned int code_len = OPCODE_BUFSIZE;

		unsigned char c;

		u8 *ip;

CRA Git | Maintained and supported by SUSTech CRA and CCSE