Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=a25bd94964e87b1b93903a822fba5025d995d4da
Commit: a25bd94964e87b1b93903a822fba5025d995d4da
Parent: 6dab27784b2a97823b522e1cb88e40be40a93d45
Author: Arjan van de Ven <[EMAIL PROTECTED]>
AuthorDate: Wed Jan 30 13:33:08 2008 +0100
Committer: Ingo Molnar <[EMAIL PROTECTED]>
CommitDate: Wed Jan 30 13:33:08 2008 +0100
x86: add the "print code before the trapping instruction" feature to 64 bit
The 32 bit x86 tree has a very useful feature that prints the Code: line
for the code even before the trapping instrution (and the start of the
trapping instruction is then denoted with a <>). Unfortunately, the 64 bit
x86 tree does not yet have this feature, making diagnosing backtraces harder
than needed.
This patch adds this feature in the same was as the 32 bit tree has
(including the same kernel boot parameter), and including a bugfix
to make the code use probe_kernel_address() rarther than a buggy
(deadlocking)
__get_user.
Signed-off-by: Arjan van de Ven <[EMAIL PROTECTED]>
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
---
Documentation/kernel-parameters.txt | 4 +-
arch/x86/kernel/traps_64.c | 44 ++++++++++++++++++++++++++--------
2 files changed, 35 insertions(+), 13 deletions(-)
diff --git a/Documentation/kernel-parameters.txt
b/Documentation/kernel-parameters.txt
index e7910f8..40db7dd 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -416,8 +416,8 @@ and is between 256 and 4096 characters. It is defined in
the file
[SPARC64] tick
[X86-64] hpet,tsc
- code_bytes [IA32] How many bytes of object code to print in an
- oops report.
+ code_bytes [IA32/X86_64] How many bytes of object code to print
+ in an oops report.
Range: 0 - 8192
Default: 64
diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c
index 304ca6b..0bba792 100644
--- a/arch/x86/kernel/traps_64.c
+++ b/arch/x86/kernel/traps_64.c
@@ -74,6 +74,8 @@ asmlinkage void alignment_check(void);
asmlinkage void machine_check(void);
asmlinkage void spurious_interrupt_bug(void);
+static unsigned int code_bytes = 64;
+
static inline void conditional_sti(struct pt_regs *regs)
{
if (regs->flags & X86_EFLAGS_IF)
@@ -459,12 +461,15 @@ EXPORT_SYMBOL(dump_stack);
void show_registers(struct pt_regs *regs)
{
int i;
- int in_kernel = !user_mode(regs);
unsigned long sp;
const int cpu = smp_processor_id();
struct task_struct *cur = cpu_pda(cpu)->pcurrent;
+ u8 *ip;
+ unsigned int code_prologue = code_bytes * 43 / 64;
+ unsigned int code_len = code_bytes;
sp = regs->sp;
+ ip = (u8 *) regs->ip - code_prologue;
printk("CPU %d ", cpu);
__show_regs(regs);
printk("Process %s (pid: %d, threadinfo %p, task %p)\n",
@@ -474,22 +479,28 @@ void show_registers(struct pt_regs *regs)
* When in-kernel, we also print out the stack and code at the
* time of the fault..
*/
- if (in_kernel) {
+ if (!user_mode(regs)) {
+ unsigned char c;
printk("Stack: ");
_show_stack(NULL, regs, (unsigned long *)sp, regs->bp);
+ printk("\n");
- printk("\nCode: ");
- if (regs->ip < PAGE_OFFSET)
- goto bad;
-
- for (i=0; i<20; i++) {
- unsigned char c;
- if (__get_user(c, &((unsigned char*)regs->ip)[i])) {
-bad:
+ printk(KERN_EMERG "Code: ");
+ if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
+ /* try starting at RIP */
+ ip = (u8 *) regs->ip;
+ code_len = code_len - code_prologue + 1;
+ }
+ for (i = 0; i < code_len; i++, ip++) {
+ if (ip < (u8 *)PAGE_OFFSET ||
+ probe_kernel_address(ip, c)) {
printk(" Bad RIP value.");
break;
}
- printk("%02x ", c);
+ if (ip == (u8 *)regs->ip)
+ printk("<%02x> ", c);
+ else
+ printk("%02x ", c);
}
}
printk("\n");
@@ -1164,3 +1175,14 @@ static int __init kstack_setup(char *s)
return 0;
}
early_param("kstack", kstack_setup);
+
+
+static int __init code_bytes_setup(char *s)
+{
+ code_bytes = simple_strtoul(s, NULL, 0);
+ if (code_bytes > 8192)
+ code_bytes = 8192;
+
+ return 1;
+}
+__setup("code_bytes=", code_bytes_setup);
-
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