ELUD: Replace a raw function pointer with base::RepeatingCallback

Uses a base::RepeatingCallback in order to resolve a layering
violation instead of using a raw function pointer to the callback.

Bug: 40944045
Change-Id: I6d36bb9186dbfda61b48f92f4b544df9bf69acdc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5501158
Reviewed-by: Matthew Denton <mpdenton@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Siddhartha S <ssid@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1295354}

base/trace_event/malloc_dump_provider.cc

@@ -41,6 +41,7 @@
 #endif
 
 #if PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
+#include "base/no_destructor.h"
 #include "partition_alloc/shim/allocator_shim_default_dispatch_to_partition_alloc.h"
 #endif
 
@@ -317,16 +318,21 @@ MallocDumpProvider* MallocDumpProvider::GetInstance() {
 }
 
 #if PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
-// static
-MallocDumpProvider::ExtremeLUDGetStatsCallback
-    MallocDumpProvider::extreme_lud_get_stats_callback_ = nullptr;
-
 // static
 void MallocDumpProvider::SetExtremeLUDGetStatsCallback(
     ExtremeLUDGetStatsCallback callback) {
-  DCHECK(callback);
-  DCHECK(!extreme_lud_get_stats_callback_);
-  extreme_lud_get_stats_callback_ = callback;
+  DCHECK(!callback.is_null());
+  auto& extreme_lud_get_stats_callback = GetExtremeLUDGetStatsCallback();
+  DCHECK(extreme_lud_get_stats_callback.is_null());
+  extreme_lud_get_stats_callback = std::move(callback);
+}
+
+// static
+MallocDumpProvider::ExtremeLUDGetStatsCallback&
+MallocDumpProvider::GetExtremeLUDGetStatsCallback() {
+  static NoDestructor<MallocDumpProvider::ExtremeLUDGetStatsCallback>
+      extreme_lud_get_stats_callback;
+  return *extreme_lud_get_stats_callback;
 }
 #endif  // PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
 
@@ -438,9 +444,11 @@ bool MallocDumpProvider::OnMemoryDump(const MemoryDumpArgs& args,
   partitions_dump = pmd->CreateAllocatorDump("malloc/partitions");
   pmd->AddOwnershipEdge(inner_dump->guid(), partitions_dump->guid());
 
-  if (extreme_lud_get_stats_callback_) {  // The Extreme LUD is enabled.
+  auto& extreme_lud_get_stats_callback = GetExtremeLUDGetStatsCallback();
+  if (!extreme_lud_get_stats_callback.is_null()) {
+    // The Extreme LUD is enabled.
     elud_dump = pmd->CreateAllocatorDump("malloc/extreme_lud");
-    elud_stats = extreme_lud_get_stats_callback_();
+    elud_stats = extreme_lud_get_stats_callback.Run();
     ReportPartitionAllocLightweightQuarantineStats(elud_dump,
                                                    elud_stats.lq_stats);
   }

base/trace_event/malloc_dump_provider.h

@@ -7,6 +7,7 @@
 
 #include "base/allocator/buildflags.h"
 #include "base/base_export.h"
+#include "base/functional/callback.h"
 #include "base/memory/raw_ptr.h"
 #include "base/memory/singleton.h"
 #include "base/synchronization/lock.h"
@@ -44,7 +45,7 @@ class BASE_EXPORT MallocDumpProvider : public MemoryDumpProvider {
     size_t capacity_in_bytes = 0;
   };
 #if PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
-  using ExtremeLUDGetStatsCallback = ExtremeLUDStats (*)();
+  using ExtremeLUDGetStatsCallback = RepeatingCallback<ExtremeLUDStats()>;
   static void SetExtremeLUDGetStatsCallback(
       ExtremeLUDGetStatsCallback callback);
 #endif  // PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
@@ -75,9 +76,9 @@ class BASE_EXPORT MallocDumpProvider : public MemoryDumpProvider {
   base::Lock emit_metrics_on_memory_dump_lock_;
 
 #if PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
-  // The injected stats-report function of the Extreme LUD. Non-null iff the
-  // Extreme LUD is enabled.
-  static ExtremeLUDGetStatsCallback extreme_lud_get_stats_callback_;
+  // Returns a reference to the injected stats-report function of the Extreme
+  // LUD. The returned callback is_null() if the Extreme LUD is not enabled.
+  static ExtremeLUDGetStatsCallback& GetExtremeLUDGetStatsCallback();
   // To be accurate, this requires the dump provider to be created very early,
   // which is the case. The alternative would be to drop the first data point,
   // which is not desirable as early process activity is highly relevant.
@@ -88,7 +89,7 @@ class BASE_EXPORT MallocDumpProvider : public MemoryDumpProvider {
   size_t last_cumulative_elud_quarantined_bytes_ = 0;
   size_t last_cumulative_elud_quarantined_count_ = 0;
   size_t last_cumulative_elud_miss_count_ = 0;
-#endif
+#endif  // PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
 };
 
 #if PA_BUILDFLAG(USE_PARTITION_ALLOC)

components/gwp_asan/client/extreme_lightweight_detector_malloc_shims.cc

@@ -6,6 +6,7 @@
 
 #include <atomic>
 
+#include "base/functional/bind.h"
 #include "base/no_destructor.h"
 #include "base/trace_event/malloc_dump_provider.h"
 #include "components/gwp_asan/client/sampling_state.h"
@@ -242,7 +243,7 @@ void InstallExtremeLightweightDetectorHooks(
 
 #if PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
   base::trace_event::MallocDumpProvider::SetExtremeLUDGetStatsCallback(
-      GetStats);
+      base::BindRepeating(GetStats));
 #endif  // PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
 }