df9d177aa2
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>
59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
/**
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* @file cpu_buffer.h
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*
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* @remark Copyright 2002 OProfile authors
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* @remark Read the file COPYING
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*
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* @author John Levon <levon@movementarian.org>
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*/
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#ifndef OPROFILE_CPU_BUFFER_H
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#define OPROFILE_CPU_BUFFER_H
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#include <linux/types.h>
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#include <linux/spinlock.h>
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#include <linux/workqueue.h>
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#include <linux/cache.h>
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struct task_struct;
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int alloc_cpu_buffers(void);
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void free_cpu_buffers(void);
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void start_cpu_work(void);
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void end_cpu_work(void);
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/* CPU buffer is composed of such entries (which are
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* also used for context switch notes)
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*/
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struct op_sample {
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unsigned long eip;
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unsigned long event;
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};
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struct oprofile_cpu_buffer {
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volatile unsigned long head_pos;
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volatile unsigned long tail_pos;
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unsigned long buffer_size;
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struct task_struct * last_task;
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int last_is_kernel;
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int tracing;
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struct op_sample * buffer;
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unsigned long sample_received;
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unsigned long sample_lost_overflow;
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unsigned long backtrace_aborted;
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unsigned long sample_invalid_eip;
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int cpu;
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struct delayed_work work;
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} ____cacheline_aligned;
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extern struct oprofile_cpu_buffer cpu_buffer[];
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void cpu_buffer_reset(struct oprofile_cpu_buffer * cpu_buf);
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/* transient events for the CPU buffer -> event buffer */
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#define CPU_IS_KERNEL 1
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#define CPU_TRACE_BEGIN 2
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#endif /* OPROFILE_CPU_BUFFER_H */
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