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:
[ 93.534801] Process insmod (pid: 1587, stack limit = 0xffffffc976be4058)
[ 93.541441] Stack: (0xffffffc976be7cf0 to 0xffffffc976be8000)
[ 93.547136] 7ce0: ffffffc976be7d00 ffffffc00008163c
[ 93.554898] 7d00: ffffffc976be7d40 ffffffc0000f8a44 ffffffc00098ef38 ffffffbffc000088
[ 93.562659] 7d20: ffffffc00098ef50 ffffffbffc0000c0 0000000000000001 ffffffbffc000070
[ 93.570419] 7d40: ffffffc976be7e40 ffffffc0000f935c 0000000000000000 000000002b424090
[ 93.578179] 7d60: 000000002b424010 0000007facc555f4 0000000080000000 0000000000000015
[ 93.585937] 7d80: 0000000000000116 0000000000000069 ffffffc00097b000 ffffffc976be4000
[ 93.593694] 7da0: 0000000000000064 0000000000000072 000000000000006e 000000000000003f
[ 93.601453] 7dc0: 000000000000feff 000000000000fff1 ffffffbffc002028 0000000000000124
[ 93.609211] 7de0: ffffffc976be7e10 0000000000000001 ffffff8000000000 ffffffbbffff0000
[ 93.616969] 7e00: ffffffc976be7e60 0000000000000000 0000000000000000 0000000000000000
[ 93.624726] 7e20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[ 93.632484] 7e40: 0000007fcc474550 ffffffc0000841ec 000000002b424010 0000007facda0710
[ 93.640241] 7e60: ffffffffffffffff ffffffc0000be6dc ffffff80007d2000 000000000001c010
[ 93.647999] 7e80: ffffff80007e0ae0 ffffff80007e09d0 ffffff80007edf70 0000000000000288
[ 93.655757] 7ea0: 00000000000002e8 0000000000000000 0000000000000000 0000001c0000001b
[ 93.663514] 7ec0: 0000000000000009 0000000000000007 000000002b424090 000000000001c010
[ 93.671272] 7ee0: 000000002b424010 0000007faccd3a48 0000000000000000 0000000000000000
[ 93.679030] 7f00: 0000007fcc4743f8 0000007fcc4743f8 0000000000000069 0000000000000003
[ 93.686787] 7f20: 0101010101010101 0000000000000004 0000000000000020 00000000000003f3
[ 93.694544] 7f40: 0000007facb95664 0000007facda7030 0000007facc555d0 0000000000498378
[ 93.702301] 7f60: 0000000000000000 000000002b424010 0000007facda0710 000000002b424090
[ 93.710058] 7f80: 0000007fcc474698 0000000000498000 0000007fcc474ebb 0000000000474f58
[ 93.717815] 7fa0: 0000000000498000 0000000000000000 0000000000000000 0000007fcc474550
[ 93.725573] 7fc0: 00000000004104bc 0000007fcc474430 0000007facc555f4 0000000080000000
[ 93.733330] 7fe0: 000000002b424090 0000000000000069 0950020128000244 4104000008000004
[ 93.741084] 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]>
---
v1: added new function dump_mem64
v2: Removed the separate function dump_mem64 and accommodated
a field width based on which the dump shall be created of
width either 4 or 8 as suggested by Catalin.
v3: Changelog modified
arch/arm64/kernel/traps.c | 44 +++++++++++++++++++++++++++++++++-----------
1 file changed, 33 insertions(+), 11 deletions(-)
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 1ef2940..53d57db 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -51,8 +51,9 @@ int show_unhandled_signals = 1;
/*
* Dump out the contents of some memory nicely...
*/
+
static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
- unsigned long top)
+ unsigned long top, unsigned int width)
{
unsigned long first;
mm_segment_t fs;
@@ -70,18 +71,27 @@ static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
for (first = bottom & ~31; first < top; first += 32) {
unsigned long p;
- char str[sizeof(" 12345678") * 8 + 1];
+ char str[sizeof(" 1234567812345678") * 8 + 1];
memset(str, ' ', sizeof(str));
str[sizeof(str) - 1] = '\0';
- for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
+ for (p = first, i = 0; i < (width > 4 ? width-4 : width+4)
+ && p < top; i++, p += width) {
if (p >= bottom && p < top) {
- unsigned int val;
- if (__get_user(val, (unsigned int *)p) == 0)
- sprintf(str + i * 9, " %08x", val);
- else
- sprintf(str + i * 9, " ????????");
+ unsigned long val;
+
+ if (width == 8) {
+ if (__get_user(val, (unsigned long *)p) == 0)
+ sprintf(str + i * 17, " %016lx", val);
+ else
+ sprintf(str + i * 17, " ????????????????");
+ } else {
+ if (__get_user(val, (unsigned int *)p) == 0)
+ sprintf(str + i * 9, " %08x", (unsigned int)val);
+ else
+ sprintf(str + i * 9, " ????????");
+ }
}
}
printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
@@ -95,7 +105,7 @@ static void dump_backtrace_entry(unsigned long where, unsigned long stack)
print_ip_sym(where);
if (in_exception_text(where))
dump_mem("", "Exception stack", stack,
- stack + sizeof(struct pt_regs));
+ stack + sizeof(struct pt_regs), 8);
}
static void dump_instr(const char *lvl, struct pt_regs *regs)
@@ -191,6 +201,7 @@ static int __die(const char *str, int err, struct thread_info *thread,
struct task_struct *tsk = thread->task;
static int die_counter;
int ret;
+ unsigned int width = 8;
pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
str, err, ++die_counter);
@@ -206,8 +217,19 @@ 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_mem(KERN_EMERG, "Stack: ", regs->sp,
+ THREAD_SIZE +
+ (unsigned long)task_stack_page(tsk), width);
+ } else {
+ if (compat_user_mode(regs))
+ width = 4;
+ dump_mem(KERN_EMERG, "Stack: ",
+ (unsigned long)task_stack_page(tsk),
+ THREAD_SIZE +
+ (unsigned long)task_stack_page(tsk), width);
+ }
dump_backtrace(regs, tsk);
dump_instr(KERN_EMERG, regs);
}
--
1.7.9.5
On Tue, Jul 07, 2015 at 10:03:15AM +0530, Maninder Singh wrote:
> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
> index 1ef2940..53d57db 100644
> --- a/arch/arm64/kernel/traps.c
> +++ b/arch/arm64/kernel/traps.c
> @@ -51,8 +51,9 @@ int show_unhandled_signals = 1;
> /*
> * Dump out the contents of some memory nicely...
> */
> +
Unnecessary empty line added here.
> static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
> - unsigned long top)
> + unsigned long top, unsigned int width)
I would add a WARN_ON(width != 4 || width != 8).
Alternatively, just change this to a "bool wide" argument and a local
width variable (it helps with the is_compat_thread below).
> {
> unsigned long first;
> mm_segment_t fs;
> @@ -70,18 +71,27 @@ static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
>
> for (first = bottom & ~31; first < top; first += 32) {
> unsigned long p;
> - char str[sizeof(" 12345678") * 8 + 1];
> + char str[sizeof(" 1234567812345678") * 8 + 1];
Does this need to be just "* 4" for 8 byte width? In which case, the
original size covers it since you just have a few spaces less.
> memset(str, ' ', sizeof(str));
> str[sizeof(str) - 1] = '\0';
>
> - for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
> + for (p = first, i = 0; i < (width > 4 ? width-4 : width+4)
> + && p < top; i++, p += width) {
It's probably clearer as:
for (p = first, i = 0; i < 32 / width && p < top; i++, p += width)
(the upper limit for i is 32-bytes per line divided by how many bytes we
read at once: 4 or 8)
> if (p >= bottom && p < top) {
> - unsigned int val;
> - if (__get_user(val, (unsigned int *)p) == 0)
> - sprintf(str + i * 9, " %08x", val);
> - else
> - sprintf(str + i * 9, " ????????");
> + unsigned long val;
> +
> + if (width == 8) {
> + if (__get_user(val, (unsigned long *)p) == 0)
> + sprintf(str + i * 17, " %016lx", val);
> + else
> + sprintf(str + i * 17, " ????????????????");
> + } else {
> + if (__get_user(val, (unsigned int *)p) == 0)
> + sprintf(str + i * 9, " %08x", (unsigned int)val);
I don't think you need the (unsigned int) cast here, just " %08lx".
> @@ -95,7 +105,7 @@ static void dump_backtrace_entry(unsigned long where, unsigned long stack)
> print_ip_sym(where);
> if (in_exception_text(where))
> dump_mem("", "Exception stack", stack,
> - stack + sizeof(struct pt_regs));
> + stack + sizeof(struct pt_regs), 8);
> }
>
> static void dump_instr(const char *lvl, struct pt_regs *regs)
> @@ -191,6 +201,7 @@ static int __die(const char *str, int err, struct thread_info *thread,
> struct task_struct *tsk = thread->task;
> static int die_counter;
> int ret;
> + unsigned int width = 8;
You could just set width here:
unsigned int width = is_compat_thread(thread) ? 4 : 8;
Or, if you pass the argument as bool to dump_mem, just use
is_compat_thread() directly.
>
> pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
> str, err, ++die_counter);
> @@ -206,8 +217,19 @@ 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_mem(KERN_EMERG, "Stack: ", regs->sp,
> + THREAD_SIZE +
> + (unsigned long)task_stack_page(tsk), width);
> + } else {
> + if (compat_user_mode(regs))
> + width = 4;
> + dump_mem(KERN_EMERG, "Stack: ",
> + (unsigned long)task_stack_page(tsk),
> + THREAD_SIZE +
> + (unsigned long)task_stack_page(tsk), width);
> + }
I don't understand this change. If you have a good reason for it, please
add it as a separate patch as it doesn't look to me like it has anything
to do with the width as described in this patch.
--
Catalin