On 9/10/21 16:10, Imran Khan wrote:

To print stack entries into a buffer, users of stackdepot, first get a list of stack entries using stack_depot_fetch and then print this list into a buffer using stack_trace_snprint. Provide a helper in stackdepot for this purpose. Also change above mentioned users to use this helper.

Signed-off-by: Imran Khan imran.f.khan@oracle.com Suggested-by: Vlastimil Babka vbabka@suse.cz

Acked-by: Vlastimil Babka vbabka@suse.cz

A comment below:

--- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -214,6 +214,29 @@ static inline struct stack_record *find_stack(struct stack_record *bucket, return NULL; }

+/**

• • stack_depot_snprint - print stack entries from a depot into a buffer
• • @handle: Stack depot handle which was returned from

• • stack_depot_save().
    

• • @buf: Pointer to the print buffer
• • @size: Size of the print buffer
• • @spaces: Number of leading spaces to print
• • Return: Number of bytes printed.
• */

+int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size,

•        int spaces)
  

+{

• unsigned long *entries;
• unsigned int nr_entries;
• nr_entries = stack_depot_fetch(handle, &entries);
• return stack_trace_snprint(buf, size, entries, nr_entries, 0);

stack_trace_snprint() has a WARN_ON(!entries). So maybe we should not call it if nr_entries is 0 (because e.g. handle was 0) as the warnings are not useful in that case.

On Sat, 11 Sep 2021, Imran Khan imran.f.khan@oracle.com wrote:

To print stack entries into a buffer, users of stackdepot, first get a list of stack entries using stack_depot_fetch and then print this list into a buffer using stack_trace_snprint. Provide a helper in stackdepot for this purpose. Also change above mentioned users to use this helper.

Signed-off-by: Imran Khan imran.f.khan@oracle.com Suggested-by: Vlastimil Babka vbabka@suse.cz

---

drivers/gpu/drm/drm_dp_mst_topology.c | 5 +---- drivers/gpu/drm/drm_mm.c | 5 +---- drivers/gpu/drm/i915/i915_vma.c | 5 +---- drivers/gpu/drm/i915/intel_runtime_pm.c | 20 +++++---------------

For the i915 parts,

Acked-by: Jani Nikula jani.nikula@intel.com

for merging via whichever tree suits you best.

include/linux/stackdepot.h | 3 +++ lib/stackdepot.c | 23 +++++++++++++++++++++++ mm/page_owner.c | 5 +---- 7 files changed, 35 insertions(+), 31 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 86d13d6bc463..2d1adab9e360 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -1668,13 +1668,10 @@ __dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history, for (i = 0; i < history->len; i++) { const struct drm_dp_mst_topology_ref_entry *entry = &history->entries[i];

• ulong *entries;
  

• uint nr_entries;
  

  u64 ts_nsec = entry->ts_nsec; u32 rem_nsec = do_div(ts_nsec, 1000000000);

• nr_entries = stack_depot_fetch(entry->backtrace, &entries);
  

• stack_trace_snprint(buf, PAGE_SIZE, entries, nr_entries, 4);
  

• stack_depot_snprint(entry->backtrace, buf, PAGE_SIZE, 4);
  
  

  drm_printf(&p, " %d %ss (last at %5llu.%06u):\n%s", entry->count,

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c index 93d48a6f04ab..ca04d7f6f7b5 100644 --- a/drivers/gpu/drm/drm_mm.c +++ b/drivers/gpu/drm/drm_mm.c @@ -118,8 +118,6 @@ static noinline void save_stack(struct drm_mm_node *node) static void show_leaks(struct drm_mm *mm) { struct drm_mm_node *node;

• unsigned long *entries;

• unsigned int nr_entries; char *buf;

  buf = kmalloc(BUFSZ, GFP_KERNEL);

@@ -133,8 +131,7 @@ static void show_leaks(struct drm_mm *mm) continue; }

• nr_entries = stack_depot_fetch(node->stack, &entries);
  

• stack_trace_snprint(buf, BUFSZ, entries, nr_entries, 0);
  

• stack_depot_snprint(node->stack, buf, BUFSZ);
  

  DRM_ERROR("node [%08llx + %08llx]: inserted at\n%s", node->start, node->size, buf); }

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index 4b7fc4647e46..f2d9ed375109 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -56,8 +56,6 @@ void i915_vma_free(struct i915_vma *vma)

static void vma_print_allocator(struct i915_vma *vma, const char *reason) {

• unsigned long *entries;

• unsigned int nr_entries; char buf[512];

  if (!vma->node.stack) {

@@ -66,8 +64,7 @@ static void vma_print_allocator(struct i915_vma *vma, const char *reason) return; }

• nr_entries = stack_depot_fetch(vma->node.stack, &entries);
• stack_trace_snprint(buf, sizeof(buf), entries, nr_entries, 0);

• stack_depot_snprint(vma->node.stack, buf, sizeof(buf), 0); DRM_DEBUG_DRIVER("vma.node [%08llx + %08llx] %s: inserted at %s\n", vma->node.start, vma->node.size, reason, buf);

} diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c index eaf7688f517d..cc312f0a05eb 100644 --- a/drivers/gpu/drm/i915/intel_runtime_pm.c +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c @@ -65,16 +65,6 @@ static noinline depot_stack_handle_t __save_depot_stack(void) return stack_depot_save(entries, n, GFP_NOWAIT | __GFP_NOWARN); }

-static void __print_depot_stack(depot_stack_handle_t stack,

• 		char *buf, int sz, int indent)
  

-{

• unsigned long *entries;
• unsigned int nr_entries;
• nr_entries = stack_depot_fetch(stack, &entries);
• stack_trace_snprint(buf, sz, entries, nr_entries, indent);

-}

static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm) { spin_lock_init(&rpm->debug.lock); @@ -146,12 +136,12 @@ static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, if (!buf) return;

• __print_depot_stack(stack, buf, PAGE_SIZE, 2);
  

• stack_depot_snprint(stack, buf, PAGE_SIZE, 2);
  

  DRM_DEBUG_DRIVER("wakeref %x from\n%s", stack, buf);

  stack = READ_ONCE(rpm->debug.last_release); if (stack) {

• 	__print_depot_stack(stack, buf, PAGE_SIZE, 2);
  

• 	stack_depot_snprint(stack, buf, PAGE_SIZE, 2);
  DRM_DEBUG_DRIVER("wakeref last released at\n%s", buf);
  

  }

@@ -183,12 +173,12 @@ __print_intel_runtime_pm_wakeref(struct drm_printer *p, return;

if (dbg->last_acquire) {

• __print_depot_stack(dbg->last_acquire, buf, PAGE_SIZE, 2);
  

• stack_depot_snprint(dbg->last_acquire, buf, PAGE_SIZE, 2);
  

  drm_printf(p, "Wakeref last acquired:\n%s", buf); }

  if (dbg->last_release) {

• __print_depot_stack(dbg->last_release, buf, PAGE_SIZE, 2);
  

• stack_depot_snprint(dbg->last_release, buf, PAGE_SIZE, 2);
  

  drm_printf(p, "Wakeref last released:\n%s", buf); }

@@ -203,7 +193,7 @@ __print_intel_runtime_pm_wakeref(struct drm_printer *p, rep = 1; while (i + 1 < dbg->count && dbg->owners[i + 1] == stack) rep++, i++;

• __print_depot_stack(stack, buf, PAGE_SIZE, 2);
  

• stack_depot_print(stack, buf, PAGE_SIZE, 2);
  

  drm_printf(p, "Wakeref x%lu taken at:\n%s", rep, buf); }

diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index d77a30543dd4..88b0b4cc9906 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -19,6 +19,9 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries, unsigned int stack_depot_fetch(depot_stack_handle_t handle, unsigned long **entries);

+int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size,

•        int spaces);
  

void stack_depot_print(depot_stack_handle_t stack);

unsigned int filter_irq_stacks(unsigned long *entries, unsigned int nr_entries); diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 873aeb152f52..e1c1d7683f6b 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -214,6 +214,29 @@ static inline struct stack_record *find_stack(struct stack_record *bucket, return NULL; }

+/**

• • stack_depot_snprint - print stack entries from a depot into a buffer
• • @handle: Stack depot handle which was returned from

• • stack_depot_save().
    

• • @buf: Pointer to the print buffer
• • @size: Size of the print buffer
• • @spaces: Number of leading spaces to print
• • Return: Number of bytes printed.
• */

+int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size,

•        int spaces)
  

+{

• unsigned long *entries;
• unsigned int nr_entries;
• nr_entries = stack_depot_fetch(handle, &entries);
• return stack_trace_snprint(buf, size, entries, nr_entries, 0);

+}

/**

• stack_depot_print - print stack entries from a depot

diff --git a/mm/page_owner.c b/mm/page_owner.c index 7918770c2b2b..a83f546c06b5 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -329,8 +329,6 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, depot_stack_handle_t handle) { int ret, pageblock_mt, page_mt;

• unsigned long *entries;

• unsigned int nr_entries; char *kbuf;

  count = min_t(size_t, count, PAGE_SIZE);

@@ -361,8 +359,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, if (ret >= count) goto err;

• nr_entries = stack_depot_fetch(handle, &entries);
• ret += stack_trace_snprint(kbuf + ret, count - ret, entries, nr_entries, 0);

• ret += stack_depot_snprint(handle, kbuf + ret, count - ret, 0); if (ret >= count) goto err;