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| author | Philippe Elie <phil.el@wanadoo.fr> | 2007-11-14 16:58:48 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-11-14 18:45:37 -0800 |
| commit | df9d177aa28d50e64bae6fbd6b263833079e3571 (patch) | |
| tree | b265158232a39d9d45cac0a97d5fdc17e7ca237d /drivers/oprofile | |
| parent | 03ad369ac900116f35da7505f768ebbd481d09a4 (diff) | |
| download | lwn-df9d177aa28d50e64bae6fbd6b263833079e3571.tar.gz lwn-df9d177aa28d50e64bae6fbd6b263833079e3571.zip | |
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>
Diffstat (limited to 'drivers/oprofile')
| -rw-r--r-- | drivers/oprofile/cpu_buffer.c | 7 | ||||
| -rw-r--r-- | drivers/oprofile/cpu_buffer.h | 1 | ||||
| -rw-r--r-- | drivers/oprofile/oprofile_stats.c | 4 |
3 files changed, 12 insertions, 0 deletions
diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c index a83c3db7d18f..c93d3d2640ab 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 49900d9e3235..c66c025abe75 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 f0acb661c253..d1f6d776e9e4 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", |