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>
This commit is contained in:
parent
03ad369ac9
commit
df9d177aa2
|
@ -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;
|
||||
|
|
|
@ -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;
|
||||
|
|
|
@ -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",
|
||||
|
|
Loading…
Reference in New Issue