Commit a124c28e authored by Don Mullis's avatar Don Mullis Committed by Linus Torvalds
Browse files

[PATCH] fault-injection: Clamp debugfs stacktrace-depth to MAX_STACK_TRACE_DEPTH 



Clamp /debug/fail*/stacktrace-depth to MAX_STACK_TRACE_DEPTH.  Ensures that a
read of /debug/fail*/stacktrace-depth always returns a truthful answer.

Signed-off-by: default avatarDon Mullis <dwm@meer.net>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 08b3df2d

lib/fault-inject.c

+23 −4
Original line number Diff line number Diff line
@@ -53,6 +53,8 @@ static bool fail_task(struct fault_attr *attr, struct task_struct *task) 
	return !in_interrupt() && task->make_it_fail;

}



#define MAX_STACK_TRACE_DEPTH 32



#ifdef CONFIG_STACK_UNWIND



static asmlinkage int fail_stacktrace_callback(struct unwind_frame_info *info,
@@ -98,8 +100,7 @@ static bool fail_stacktrace(struct fault_attr *attr) 


	trace.nr_entries = 0;

	trace.entries = entries;

	trace.max_entries = (depth < MAX_STACK_TRACE_DEPTH) ?

				depth : MAX_STACK_TRACE_DEPTH;

	trace.max_entries = depth;

	trace.skip = 1;

	trace.all_contexts = 0;
@@ -179,6 +180,13 @@ static void debugfs_ul_set(void *data, u64 val) 
	*(unsigned long *)data = val;

}



static void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val)

{

	*(unsigned long *)data =

		val < MAX_STACK_TRACE_DEPTH ?

		val : MAX_STACK_TRACE_DEPTH;

}



static u64 debugfs_ul_get(void *data)

{

	return *(unsigned long *)data;
@@ -192,6 +200,17 @@ static struct dentry *debugfs_create_ul(const char *name, mode_t mode, 
	return debugfs_create_file(name, mode, parent, value, &fops_ul);

}



DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get,

			debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n");



static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH(

	const char *name, mode_t mode,

	struct dentry *parent, unsigned long *value)

{

	return debugfs_create_file(name, mode, parent, value,

				   &fops_ul_MAX_STACK_TRACE_DEPTH);

}



static void debugfs_atomic_t_set(void *data, u64 val)

{

	atomic_set((atomic_t *)data, val);
@@ -284,8 +303,8 @@ int init_fault_attr_dentries(struct fault_attr *attr, const char *name) 
						mode, dir, &attr->task_filter);



	attr->dentries.stacktrace_depth_file =

		debugfs_create_ul("stacktrace-depth", mode, dir,

				  &attr->stacktrace_depth);

		debugfs_create_ul_MAX_STACK_TRACE_DEPTH(

			"stacktrace-depth", mode, dir, &attr->stacktrace_depth);



	attr->dentries.require_start_file =

		debugfs_create_ul("require-start", mode, dir, &attr->require_start);