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Subject[PATCH V3] Split executable and non-executable mmap tracking
Date
This patch splits tracking of executable and non-executable mmaps.
Executable mmaps are tracked normally and non-executable are
tracked when --data is used.

Signed-off-by: Anton Blanchard <anton@samba.org>

Updated code for stable perf ABI
Signed-off-by: Eric B Munson <ebmunson@us.ibm.com>
---
Changes from V2:
-In free_event and perf_event_mmap, collapse the attr.mmap and attr.mmap_data
if statements into a single or'd if
-Add perf_mmap_event call in expand_upwards to match call in expand_downwards

Changes from V1:
-Changed mmap_exec to mmap_data and left mmap as the executable mmap tracker
to maintain backwards compatibility
-Insert mmap_data at the end of the attr bit map
---
fs/exec.c | 1 +
include/linux/perf_event.h | 12 +++---------
kernel/perf_event.c | 34 +++++++++++++++++++++++-----------
mm/mmap.c | 6 +++++-
tools/perf/builtin-record.c | 4 +++-
5 files changed, 35 insertions(+), 22 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index e6e94c6..8204aef 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -648,6 +648,7 @@ int setup_arg_pages(struct linux_binprm *bprm,
else
stack_base = vma->vm_start - stack_expand;
#endif
+ current->mm->start_stack = bprm->p;
ret = expand_stack(vma, stack_base);
if (ret)
ret = -EFAULT;
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 3fd5c82..e424ee7 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -214,8 +214,9 @@ struct perf_event_attr {
* See also PERF_RECORD_MISC_EXACT_IP
*/
precise_ip : 2, /* skid constraint */
+ mmap_data : 1. /* non-exec mmap data */

- __reserved_1 : 47;
+ __reserved_1 : 46;

union {
__u32 wakeup_events; /* wakeup every n events */
@@ -956,14 +957,7 @@ perf_sw_event(u32 event_id, u64 nr, int nmi, struct pt_regs *regs, u64 addr)
}
}

-extern void __perf_event_mmap(struct vm_area_struct *vma);
-
-static inline void perf_event_mmap(struct vm_area_struct *vma)
-{
- if (vma->vm_flags & VM_EXEC)
- __perf_event_mmap(vma);
-}
-
+extern void perf_event_mmap(struct vm_area_struct *vma);
extern struct perf_guest_info_callbacks *perf_guest_cbs;
extern int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks);
extern int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks);
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index a4fa381..e7ba170 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -1848,7 +1848,7 @@ static void free_event(struct perf_event *event)

if (!event->parent) {
atomic_dec(&nr_events);
- if (event->attr.mmap)
+ if (event->attr.mmap || event->attr.mmap_data)
atomic_dec(&nr_mmap_events);
if (event->attr.comm)
atomic_dec(&nr_comm_events);
@@ -3413,7 +3413,7 @@ perf_event_read_event(struct perf_event *event,
/*
* task tracking -- fork/exit
*
- * enabled by: attr.comm | attr.mmap | attr.task
+ * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
*/

struct perf_task_event {
@@ -3473,7 +3473,8 @@ static int perf_event_task_match(struct perf_event *event)
if (event->cpu != -1 && event->cpu != smp_processor_id())
return 0;

- if (event->attr.comm || event->attr.mmap || event->attr.task)
+ if (event->attr.comm || event->attr.mmap ||
+ event->attr.mmap_data || event->attr.task)
return 1;

return 0;
@@ -3698,7 +3699,8 @@ static void perf_event_mmap_output(struct perf_event *event,
}

static int perf_event_mmap_match(struct perf_event *event,
- struct perf_mmap_event *mmap_event)
+ struct perf_mmap_event *mmap_event,
+ int executable)
{
if (event->state < PERF_EVENT_STATE_INACTIVE)
return 0;
@@ -3706,19 +3708,21 @@ static int perf_event_mmap_match(struct perf_event *event,
if (event->cpu != -1 && event->cpu != smp_processor_id())
return 0;

- if (event->attr.mmap)
+ if ((!executable && event->attr.mmap_data) ||
+ (executable && event->attr.mmap))
return 1;

return 0;
}

static void perf_event_mmap_ctx(struct perf_event_context *ctx,
- struct perf_mmap_event *mmap_event)
+ struct perf_mmap_event *mmap_event,
+ int executable)
{
struct perf_event *event;

list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
- if (perf_event_mmap_match(event, mmap_event))
+ if (perf_event_mmap_match(event, mmap_event, executable))
perf_event_mmap_output(event, mmap_event);
}
}
@@ -3762,6 +3766,14 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
if (!vma->vm_mm) {
name = strncpy(tmp, "[vdso]", sizeof(tmp));
goto got_name;
+ } else if (vma->vm_start <= vma->vm_mm->start_brk &&
+ vma->vm_end >= vma->vm_mm->brk) {
+ name = strncpy(tmp, "[heap]", sizeof(tmp));
+ goto got_name;
+ } else if (vma->vm_start <= vma->vm_mm->start_stack &&
+ vma->vm_end >= vma->vm_mm->start_stack) {
+ name = strncpy(tmp, "[stack]", sizeof(tmp));
+ goto got_name;
}

name = strncpy(tmp, "//anon", sizeof(tmp));
@@ -3778,17 +3790,17 @@ got_name:

rcu_read_lock();
cpuctx = &get_cpu_var(perf_cpu_context);
- perf_event_mmap_ctx(&cpuctx->ctx, mmap_event);
+ perf_event_mmap_ctx(&cpuctx->ctx, mmap_event, vma->vm_flags & VM_EXEC);
ctx = rcu_dereference(current->perf_event_ctxp);
if (ctx)
- perf_event_mmap_ctx(ctx, mmap_event);
+ perf_event_mmap_ctx(ctx, mmap_event, vma->vm_flags & VM_EXEC);
put_cpu_var(perf_cpu_context);
rcu_read_unlock();

kfree(buf);
}

-void __perf_event_mmap(struct vm_area_struct *vma)
+void perf_event_mmap(struct vm_area_struct *vma)
{
struct perf_mmap_event mmap_event;

@@ -4795,7 +4807,7 @@ done:

if (!event->parent) {
atomic_inc(&nr_events);
- if (event->attr.mmap)
+ if (event->attr.mmap || event->attr.mmap_data)
atomic_inc(&nr_mmap_events);
if (event->attr.comm)
atomic_inc(&nr_comm_events);
diff --git a/mm/mmap.c b/mm/mmap.c
index 456ec6f..e38e910 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1734,8 +1734,10 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
grow = (address - vma->vm_end) >> PAGE_SHIFT;

error = acct_stack_growth(vma, size, grow);
- if (!error)
+ if (!error) {
vma->vm_end = address;
+ perf_event_mmap(vma);
+ }
}
anon_vma_unlock(vma);
return error;
@@ -1781,6 +1783,7 @@ static int expand_downwards(struct vm_area_struct *vma,
if (!error) {
vma->vm_start = address;
vma->vm_pgoff -= grow;
+ perf_event_mmap(vma);
}
}
anon_vma_unlock(vma);
@@ -2208,6 +2211,7 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
vma->vm_page_prot = vm_get_page_prot(flags);
vma_link(mm, vma, prev, rb_link, rb_parent);
out:
+ perf_event_mmap(vma);
mm->total_vm += len >> PAGE_SHIFT;
if (flags & VM_LOCKED) {
if (!mlock_vma_pages_range(vma, addr, addr + len))
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index cb46c7d..d047388 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -284,8 +284,10 @@ static void create_counter(int counter, int cpu)
if (inherit_stat)
attr->inherit_stat = 1;

- if (sample_address)
+ if (sample_address) {
attr->sample_type |= PERF_SAMPLE_ADDR;
+ attr->mmap_data = track;
+ }

if (call_graph)
attr->sample_type |= PERF_SAMPLE_CALLCHAIN;
--
1.7.0.4


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