From 2ec220e27f5040aec1e88901c1b6ea3d135787ad Mon Sep 17 00:00:00 2001
From: Ken Chen <kenchen@google.com>
Date: Mon, 10 Nov 2008 11:26:08 +0300
Subject: proc: add /proc/*/stack
/proc/*/stack adds the ability to query a task's stack trace. It is more
useful than /proc/*/wchan as it provides full stack trace instead of single
depth. Example output:
$ cat /proc/self/stack
[<c010a271>] save_stack_trace_tsk+0x17/0x35
[<c01827b4>] proc_pid_stack+0x4a/0x76
[<c018312d>] proc_single_show+0x4a/0x5e
[<c016bdec>] seq_read+0xf3/0x29f
[<c015a004>] vfs_read+0x6d/0x91
[<c015a0c1>] sys_read+0x3b/0x60
[<c0102eda>] syscall_call+0x7/0xb
[<ffffffff>] 0xffffffff
[add save_stack_trace_tsk() on mips, ACK Ralf --adobriyan]
Signed-off-by: Ken Chen <kenchen@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
arch/mips/kernel/stacktrace.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
(limited to 'arch/mips/kernel/stacktrace.c')
diff --git a/arch/mips/kernel/stacktrace.c b/arch/mips/kernel/stacktrace.c
index 0632e2a849c..58f5cd76c8c 100644
--- a/arch/mips/kernel/stacktrace.c
+++ b/arch/mips/kernel/stacktrace.c
@@ -32,7 +32,8 @@ static void save_raw_context_stack(struct stack_trace *trace,
}
}
-static void save_context_stack(struct stack_trace *trace, struct pt_regs *regs)
+static void save_context_stack(struct stack_trace *trace,
+ struct task_struct *tsk, struct pt_regs *regs)
{
unsigned long sp = regs->regs[29];
#ifdef CONFIG_KALLSYMS
@@ -41,7 +42,7 @@ static void save_context_stack(struct stack_trace *trace, struct pt_regs *regs)
if (raw_show_trace || !__kernel_text_address(pc)) {
unsigned long stack_page =
- (unsigned long)task_stack_page(current);
+ (unsigned long)task_stack_page(tsk);
if (stack_page && sp >= stack_page &&
sp <= stack_page + THREAD_SIZE - 32)
save_raw_context_stack(trace, sp);
@@ -54,7 +55,7 @@ static void save_context_stack(struct stack_trace *trace, struct pt_regs *regs)
trace->entries[trace->nr_entries++] = pc;
if (trace->nr_entries >= trace->max_entries)
break;
- pc = unwind_stack(current, &sp, pc, &ra);
+ pc = unwind_stack(tsk, &sp, pc, &ra);
} while (pc);
#else
save_raw_context_stack(trace, sp);
@@ -65,13 +66,24 @@ static void save_context_stack(struct stack_trace *trace, struct pt_regs *regs)
* Save stack-backtrace addresses into a stack_trace buffer.
*/
void save_stack_trace(struct stack_trace *trace)
+{
+ save_stack_trace_tsk(current, trace);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace);
+
+void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
struct pt_regs dummyregs;
struct pt_regs *regs = &dummyregs;
WARN_ON(trace->nr_entries || !trace->max_entries);
- prepare_frametrace(regs);
- save_context_stack(trace, regs);
+ if (tsk != current) {
+ regs->regs[29] = tsk->thread.reg29;
+ regs->regs[31] = 0;
+ regs->cp0_epc = tsk->thread.reg31;
+ } else
+ prepare_frametrace(regs);
+ save_context_stack(trace, tsk, regs);
}
-EXPORT_SYMBOL_GPL(save_stack_trace);
+EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
--
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