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authorPhilippe Elie <phil.el@wanadoo.fr>2007-11-14 16:58:48 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-11-14 18:45:37 -0800
commitdf9d177aa28d50e64bae6fbd6b263833079e3571 (patch)
treeb265158232a39d9d45cac0a97d5fdc17e7ca237d
parent03ad369ac900116f35da7505f768ebbd481d09a4 (diff)
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>
-rw-r--r--drivers/oprofile/cpu_buffer.c7
-rw-r--r--drivers/oprofile/cpu_buffer.h1
-rw-r--r--drivers/oprofile/oprofile_stats.c4
3 files changed, 12 insertions, 0 deletions
diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index a83c3db7d18..c93d3d2640a 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -64,6 +64,8 @@ int alloc_cpu_buffers(void)
b->head_pos = 0;
b->sample_received = 0;
b->sample_lost_overflow = 0;
+ b->backtrace_aborted = 0;
+ b->sample_invalid_eip = 0;
b->cpu = i;
INIT_DELAYED_WORK(&b->work, wq_sync_buffer);
}
@@ -175,6 +177,11 @@ static int log_sample(struct oprofile_cpu_buffer * cpu_buf, unsigned long pc,
cpu_buf->sample_received++;
+ if (pc == ESCAPE_CODE) {
+ cpu_buf->sample_invalid_eip++;
+ return 0;
+ }
+
if (nr_available_slots(cpu_buf) < 3) {
cpu_buf->sample_lost_overflow++;
return 0;
diff --git a/drivers/oprofile/cpu_buffer.h b/drivers/oprofile/cpu_buffer.h
index 49900d9e323..c66c025abe7 100644
--- a/drivers/oprofile/cpu_buffer.h
+++ b/drivers/oprofile/cpu_buffer.h
@@ -42,6 +42,7 @@ struct oprofile_cpu_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;
diff --git a/drivers/oprofile/oprofile_stats.c b/drivers/oprofile/oprofile_stats.c
index f0acb661c25..d1f6d776e9e 100644
--- a/drivers/oprofile/oprofile_stats.c
+++ b/drivers/oprofile/oprofile_stats.c
@@ -26,6 +26,8 @@ void oprofile_reset_stats(void)
cpu_buf = &cpu_buffer[i];
cpu_buf->sample_received = 0;
cpu_buf->sample_lost_overflow = 0;
+ cpu_buf->backtrace_aborted = 0;
+ cpu_buf->sample_invalid_eip = 0;
}
atomic_set(&oprofile_stats.sample_lost_no_mm, 0);
@@ -61,6 +63,8 @@ void oprofile_create_stats_files(struct super_block * sb, struct dentry * root)
&cpu_buf->sample_lost_overflow);
oprofilefs_create_ro_ulong(sb, cpudir, "backtrace_aborted",
&cpu_buf->backtrace_aborted);
+ oprofilefs_create_ro_ulong(sb, cpudir, "sample_invalid_eip",
+ &cpu_buf->sample_invalid_eip);
}
oprofilefs_create_ro_atomic(sb, dir, "sample_lost_no_mm",