Commit 1e2af92e authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds

[PATCH] x86: use probe_kernel_address in handle_BUG()

Avoid possible deadlock on a BUG() inside down_write(mmap_sem).  The deadlock
can only occur if something has gone horridly wrong, because a fault here
shouldn't happen.
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 1b79e551
......@@ -28,6 +28,7 @@
#include <linux/kprobes.h>
#include <linux/kexec.h>
#include <linux/unwind.h>
#include <linux/uaccess.h>
#ifdef CONFIG_EISA
#include <linux/ioport.h>
......@@ -40,7 +41,6 @@
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/atomic.h>
#include <asm/debugreg.h>
......@@ -409,7 +409,7 @@ static void handle_BUG(struct pt_regs *regs)
if (eip < PAGE_OFFSET)
return;
if (__get_user(ud2, (unsigned short __user *)eip))
if (probe_kernel_address((unsigned short __user *)eip, ud2))
return;
if (ud2 != 0x0b0f)
return;
......@@ -422,7 +422,8 @@ static void handle_BUG(struct pt_regs *regs)
char *file;
char c;
if (__get_user(line, (unsigned short __user *)(eip + 2)))
if (probe_kernel_address((unsigned short __user *)(eip + 2),
line))
break;
if (__get_user(file, (char * __user *)(eip + 4)) ||
(unsigned long)file < PAGE_OFFSET || __get_user(c, file))
......
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