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x86/dumpstack: Remove code_bytes

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This was added by

  86c4183742 ("[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: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas 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
This commit is contained in:
Borislav Petkov 2018-04-17 18:11:16 +02:00 committed by Thomas Gleixner
parent 6d08b06e67
commit 5d12f0424e
2 changed files with 4 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
Documentation/admin-guide/kernel-parameters.txt
View File

@ -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>]]]]]

27
arch/x86/kernel/dumpstack.c
View File

@ -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;