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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>
79 lines
2.1 KiB
C
79 lines
2.1 KiB
C
/**
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* @file oprofile_stats.c
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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
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*/
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#include <linux/oprofile.h>
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#include <linux/smp.h>
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#include <linux/cpumask.h>
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#include <linux/threads.h>
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#include "oprofile_stats.h"
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#include "cpu_buffer.h"
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struct oprofile_stat_struct oprofile_stats;
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void oprofile_reset_stats(void)
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{
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struct oprofile_cpu_buffer * cpu_buf;
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int i;
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for_each_possible_cpu(i) {
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cpu_buf = &cpu_buffer[i];
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cpu_buf->sample_received = 0;
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cpu_buf->sample_lost_overflow = 0;
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cpu_buf->backtrace_aborted = 0;
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cpu_buf->sample_invalid_eip = 0;
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}
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atomic_set(&oprofile_stats.sample_lost_no_mm, 0);
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atomic_set(&oprofile_stats.sample_lost_no_mapping, 0);
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atomic_set(&oprofile_stats.event_lost_overflow, 0);
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}
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void oprofile_create_stats_files(struct super_block * sb, struct dentry * root)
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{
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struct oprofile_cpu_buffer * cpu_buf;
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struct dentry * cpudir;
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struct dentry * dir;
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char buf[10];
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int i;
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dir = oprofilefs_mkdir(sb, root, "stats");
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if (!dir)
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return;
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for_each_possible_cpu(i) {
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cpu_buf = &cpu_buffer[i];
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snprintf(buf, 10, "cpu%d", i);
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cpudir = oprofilefs_mkdir(sb, dir, buf);
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/* Strictly speaking access to these ulongs is racy,
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* but we can't simply lock them, and they are
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* informational only.
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*/
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oprofilefs_create_ro_ulong(sb, cpudir, "sample_received",
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&cpu_buf->sample_received);
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oprofilefs_create_ro_ulong(sb, cpudir, "sample_lost_overflow",
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&cpu_buf->sample_lost_overflow);
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oprofilefs_create_ro_ulong(sb, cpudir, "backtrace_aborted",
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&cpu_buf->backtrace_aborted);
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oprofilefs_create_ro_ulong(sb, cpudir, "sample_invalid_eip",
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&cpu_buf->sample_invalid_eip);
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}
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oprofilefs_create_ro_atomic(sb, dir, "sample_lost_no_mm",
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&oprofile_stats.sample_lost_no_mm);
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oprofilefs_create_ro_atomic(sb, dir, "sample_lost_no_mapping",
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&oprofile_stats.sample_lost_no_mapping);
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oprofilefs_create_ro_atomic(sb, dir, "event_lost_overflow",
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&oprofile_stats.event_lost_overflow);
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oprofilefs_create_ro_atomic(sb, dir, "bt_lost_no_mapping",
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&oprofile_stats.bt_lost_no_mapping);
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}
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