From: Rohit Thapliyal <[email protected]>
On 64bit kernel, the dump_mem gives 32 bit addresses
on the stack dump. This gives unorganized information regarding
the 64bit values on the stack. Hence, modified to get a complete
64bit memory dump.
With patch:
Process insmod (pid: 1587, stack limit = 0xffffffc976be4058)
Stack: (0xffffffc976be7cf0 to 0xffffffc976be8000)
7ce0: ffffffc976be7d00 ffffffc00008163c
7d00: ffffffc976be7d40 ffffffc0000f8a44 ffffffc00098ef38 ffffffbffc000088
7d20: ffffffc00098ef50 ffffffbffc0000c0 0000000000000001 ffffffbffc000070
7d40: ffffffc976be7e40 ffffffc0000f935c 0000000000000000 000000002b424090
7d60: 000000002b424010 0000007facc555f4 0000000080000000 0000000000000015
7d80: 0000000000000116 0000000000000069 ffffffc00097b000 ffffffc976be4000
7da0: 0000000000000064 0000000000000072 000000000000006e 000000000000003f
7dc0: 000000000000feff 000000000000fff1 ffffffbffc002028 0000000000000124
7de0: ffffffc976be7e10 0000000000000001 ffffff8000000000 ffffffbbffff0000
7e00: ffffffc976be7e60 0000000000000000 0000000000000000 0000000000000000
7e20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
7e40: 0000007fcc474550 ffffffc0000841ec 000000002b424010 0000007facda0710
7e60: ffffffffffffffff ffffffc0000be6dc ffffff80007d2000 000000000001c010
7e80: ffffff80007e0ae0 ffffff80007e09d0 ffffff80007edf70 0000000000000288
7ea0: 00000000000002e8 0000000000000000 0000000000000000 0000001c0000001b
7ec0: 0000000000000009 0000000000000007 000000002b424090 000000000001c010
7ee0: 000000002b424010 0000007faccd3a48 0000000000000000 0000000000000000
7f00: 0000007fcc4743f8 0000007fcc4743f8 0000000000000069 0000000000000003
7f20: 0101010101010101 0000000000000004 0000000000000020 00000000000003f3
7f40: 0000007facb95664 0000007facda7030 0000007facc555d0 0000000000498378
7f60: 0000000000000000 000000002b424010 0000007facda0710 000000002b424090
7f80: 0000007fcc474698 0000000000498000 0000007fcc474ebb 0000000000474f58
7fa0: 0000000000498000 0000000000000000 0000000000000000 0000007fcc474550
7fc0: 00000000004104bc 0000007fcc474430 0000007facc555f4 0000000080000000
7fe0: 000000002b424090 0000000000000069 0950020128000244 4104000008000004
Call trace:
The above output makes a debugger life a lot more easier.
Signed-off-by: Rohit Thapliyal <[email protected]>
Signed-off-by: Maninder Singh <[email protected]>
Reviewed-by: Akhilesh Kumar <[email protected]>
---
arch/arm64/kernel/traps.c | 62 +++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 60 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 1ef2940..6e9f19b 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -51,6 +51,48 @@ int show_unhandled_signals = 1;
/*
* Dump out the contents of some memory nicely...
*/
+
+static void dump_mem64(const char *lvl, const char *str, unsigned long bottom,
+ unsigned long top)
+{
+ unsigned long first;
+ mm_segment_t fs;
+ int i;
+
+ /*
+ * We need to switch to kernel mode so that we can use __get_user
+ * to safely read from kernel space. Note that we now dump the
+ * code first, just in case the backtrace kills us.
+ */
+ fs = get_fs();
+ set_fs(KERNEL_DS);
+
+ pr_alert("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);
+
+ for (first = bottom & ~31; first < top; first += 32) {
+ unsigned long p;
+ char str[sizeof(" 1234567812345678") * 8 + 1];
+
+ memset(str, ' ', sizeof(str));
+ str[sizeof(str) - 1] = '\0';
+
+ for (p = first, i = 0; i < 4 && p < top; i++, p += 8) {
+ if (p >= bottom && p < top) {
+ unsigned long val;
+
+ if (__get_user(val, (unsigned long *)p) == 0)
+ sprintf(str + i * 17, " %016lx", val);
+ else
+ sprintf(str + i * 17,
+ " ????????????????");
+ }
+ }
+ pr_alert("%s%04lx:%s\n", lvl, first & 0xffff, str);
+ }
+
+ set_fs(fs);
+}
+
static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
unsigned long top)
{
@@ -206,8 +248,24 @@ static int __die(const char *str, int err, struct thread_info *thread,
TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
if (!user_mode(regs) || in_interrupt()) {
- dump_mem(KERN_EMERG, "Stack: ", regs->sp,
- THREAD_SIZE + (unsigned long)task_stack_page(tsk));
+
+ if (regs->sp > (unsigned long)task_stack_page(tsk)) {
+ dump_mem64(KERN_EMERG, "Stack: ", regs->sp,
+ THREAD_SIZE +
+ (unsigned long)task_stack_page(tsk));
+ } else {
+ if (compat_user_mode(regs)) {
+ dump_mem(KERN_EMERG, "Stack: ",
+ (unsigned long)task_stack_page(tsk),
+ THREAD_SIZE +
+ (unsigned long)task_stack_page(tsk));
+ } else {
+ dump_mem64(KERN_EMERG, "Stack: ",
+ (unsigned long)task_stack_page(tsk),
+ THREAD_SIZE +
+ (unsigned long)task_stack_page(tsk));
+ }
+ }
dump_backtrace(regs, tsk);
dump_instr(KERN_EMERG, regs);
}
--
1.7.9.5
On Thu, Jun 18, 2015 at 10:57:06AM +0530, Maninder Singh wrote:
> From: Rohit Thapliyal <[email protected]>
>
> On 64bit kernel, the dump_mem gives 32 bit addresses
> on the stack dump. This gives unorganized information regarding
> the 64bit values on the stack. Hence, modified to get a complete
> 64bit memory dump.
[...]
> The above output makes a debugger life a lot more easier.
>
> Signed-off-by: Rohit Thapliyal <[email protected]>
> Signed-off-by: Maninder Singh <[email protected]>
> Reviewed-by: Akhilesh Kumar <[email protected]>
> ---
> arch/arm64/kernel/traps.c | 62 +++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 60 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
> index 1ef2940..6e9f19b 100644
> --- a/arch/arm64/kernel/traps.c
> +++ b/arch/arm64/kernel/traps.c
> @@ -51,6 +51,48 @@ int show_unhandled_signals = 1;
> /*
> * Dump out the contents of some memory nicely...
> */
> +
> +static void dump_mem64(const char *lvl, const char *str, unsigned long bottom,
> + unsigned long top)
While I'm not against the idea, can you not add a "width" or "wide"
argument to the dump_mem() function and share the code? This function is
very similar to the original dump_mem() implementation and it would be
nice to avoid some code duplication.
--
Catalin