linux/drivers/oprofile/cpu_buffer.h
Philippe Elie df9d177aa2 oProfile: oops when profile_pc() returns ~0LU
Instruction pointer returned by profile_pc() can be a random value.  This
break the assumption than we can safely set struct op_sample.eip field to a
magic value to signal to the per-cpu buffer reader side special event like
task switch ending up in a segfault in get_task_mm() when profile_pc()
return ~0UL.  Fixed by sanitizing the sampled eip and reject/log invalid
eip.

Problem reported by Sami Farin, patch tested by him.

Signed-off-by: Philippe Elie <phil.el@wanadoo.fr>
Tested-by: Sami Farin <safari-kernel@safari.iki.fi>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-14 18:45:37 -08:00

58 lines
1.3 KiB
C

/**
* @file cpu_buffer.h
*
* @remark Copyright 2002 OProfile authors
* @remark Read the file COPYING
*
* @author John Levon <levon@movementarian.org>
*/
#ifndef OPROFILE_CPU_BUFFER_H
#define OPROFILE_CPU_BUFFER_H
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/cache.h>
struct task_struct;
int alloc_cpu_buffers(void);
void free_cpu_buffers(void);
void start_cpu_work(void);
void end_cpu_work(void);
/* CPU buffer is composed of such entries (which are
* also used for context switch notes)
*/
struct op_sample {
unsigned long eip;
unsigned long event;
};
struct oprofile_cpu_buffer {
volatile unsigned long head_pos;
volatile unsigned long tail_pos;
unsigned long buffer_size;
struct task_struct * last_task;
int last_is_kernel;
int tracing;
struct op_sample * buffer;
unsigned long sample_received;
unsigned long sample_lost_overflow;
unsigned long backtrace_aborted;
unsigned long sample_invalid_eip;
int cpu;
struct delayed_work work;
} ____cacheline_aligned;
extern struct oprofile_cpu_buffer cpu_buffer[];
void cpu_buffer_reset(struct oprofile_cpu_buffer * cpu_buf);
/* transient events for the CPU buffer -> event buffer */
#define CPU_IS_KERNEL 1
#define CPU_TRACE_BEGIN 2
#endif /* OPROFILE_CPU_BUFFER_H */