[compiler-rt] r235728 - [lsan] Add an interface function for on-demand leak checking.
Sergey Matveev
earthdok at google.com
Fri Apr 24 09:53:15 PDT 2015
Author: smatveev
Date: Fri Apr 24 11:53:15 2015
New Revision: 235728
URL: http://llvm.org/viewvc/llvm-project?rev=235728&view=rev
Log:
[lsan] Add an interface function for on-demand leak checking.
Summary:
Add an interface function which can be used to periodically trigger
leak detection in a long-running process.
NB: The meaning of the kIgnored tag has been changed to allow easy clean-up
between subsequent leak checks. Previously, this tag was applied to explicitly
ignored (i.e. with __lsan_disable() or __lsan_ignore_object()) chunks *and* any
chunks only reachable from those. With this change, it's only applied to
explicitly ignored chunks.
Reviewers: samsonov
Reviewed By: samsonov
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9159
Added:
compiler-rt/trunk/test/lsan/TestCases/recoverable_leak_check.cc
Modified:
compiler-rt/trunk/include/sanitizer/lsan_interface.h
compiler-rt/trunk/lib/lsan/lsan_common.cc
compiler-rt/trunk/lib/lsan/lsan_common_linux.cc
Modified: compiler-rt/trunk/include/sanitizer/lsan_interface.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/include/sanitizer/lsan_interface.h?rev=235728&r1=235727&r2=235728&view=diff
==============================================================================
--- compiler-rt/trunk/include/sanitizer/lsan_interface.h (original)
+++ compiler-rt/trunk/include/sanitizer/lsan_interface.h Fri Apr 24 11:53:15 2015
@@ -41,14 +41,25 @@ extern "C" {
void __lsan_register_root_region(const void *p, size_t size);
void __lsan_unregister_root_region(const void *p, size_t size);
- // Calling this function makes LSan enter the leak checking phase immediately.
- // Use this if normal end-of-process leak checking happens too late (e.g. if
- // you have intentional memory leaks in your shutdown code). Calling this
- // function overrides end-of-process leak checking; it must be called at
- // most once per process. This function will terminate the process if there
- // are memory leaks and the exit_code flag is non-zero.
+ // Check for leaks now. This function behaves identically to the default
+ // end-of-process leak check. In particular, it will terminate the process if
+ // leaks are found and the exit_code flag is non-zero.
+ // Subsequent calls to this function will have no effect and end-of-process
+ // leak check will not run. Effectively, end-of-process leak check is moved to
+ // the time of first invocation of this function.
+ // By calling this function early during process shutdown, you can instruct
+ // LSan to ignore shutdown-only leaks which happen later on.
void __lsan_do_leak_check();
+ // Check for leaks now. Returns zero if no leaks have been found or if leak
+ // detection is disabled, non-zero otherwise.
+ // This function may be called repeatedly, e.g. to periodically check a
+ // long-running process. It prints a leak report if appropriate, but does not
+ // terminate the process. It does not affect the behavior of
+ // __lsan_do_leak_check() or the end-of-process leak check, and is not
+ // affected by them.
+ int __lsan_do_recoverable_leak_check();
+
// The user may optionally provide this function to disallow leak checking
// for the program it is linked into (if the return value is non-zero). This
// function must be defined as returning a constant value; any behavior beyond
Modified: compiler-rt/trunk/lib/lsan/lsan_common.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/lsan/lsan_common.cc?rev=235728&r1=235727&r2=235728&view=diff
==============================================================================
--- compiler-rt/trunk/lib/lsan/lsan_common.cc (original)
+++ compiler-rt/trunk/lib/lsan/lsan_common.cc Fri Apr 24 11:53:15 2015
@@ -126,13 +126,14 @@ static inline bool CanBeAHeapPointer(upt
// Scans the memory range, looking for byte patterns that point into allocator
// chunks. Marks those chunks with |tag| and adds them to |frontier|.
-// There are two usage modes for this function: finding reachable or ignored
-// chunks (|tag| = kReachable or kIgnored) and finding indirectly leaked chunks
+// There are two usage modes for this function: finding reachable chunks
+// (|tag| = kReachable) and finding indirectly leaked chunks
// (|tag| = kIndirectlyLeaked). In the second case, there's no flood fill,
// so |frontier| = 0.
void ScanRangeForPointers(uptr begin, uptr end,
Frontier *frontier,
const char *region_type, ChunkTag tag) {
+ CHECK(tag == kReachable || tag == kIndirectlyLeaked);
const uptr alignment = flags()->pointer_alignment();
LOG_POINTERS("Scanning %s range %p-%p.\n", region_type, begin, end);
uptr pp = begin;
@@ -146,9 +147,7 @@ void ScanRangeForPointers(uptr begin, up
// Pointers to self don't count. This matters when tag == kIndirectlyLeaked.
if (chunk == begin) continue;
LsanMetadata m(chunk);
- // Reachable beats ignored beats leaked.
- if (m.tag() == kReachable) continue;
- if (m.tag() == kIgnored && tag != kReachable) continue;
+ if (m.tag() == kReachable || m.tag() == kIgnored) continue;
// Do this check relatively late so we can log only the interesting cases.
if (!flags()->use_poisoned && WordIsPoisoned(pp)) {
@@ -287,7 +286,7 @@ static void MarkIndirectlyLeakedCb(uptr
LsanMetadata m(chunk);
if (m.allocated() && m.tag() != kReachable) {
ScanRangeForPointers(chunk, chunk + m.requested_size(),
- /* frontier */ 0, "HEAP", kIndirectlyLeaked);
+ /* frontier */ nullptr, "HEAP", kIndirectlyLeaked);
}
}
@@ -297,8 +296,11 @@ static void CollectIgnoredCb(uptr chunk,
CHECK(arg);
chunk = GetUserBegin(chunk);
LsanMetadata m(chunk);
- if (m.allocated() && m.tag() == kIgnored)
+ if (m.allocated() && m.tag() == kIgnored) {
+ LOG_POINTERS("Ignored: chunk %p-%p of size %zu.\n",
+ chunk, chunk + m.requested_size(), m.requested_size());
reinterpret_cast<Frontier *>(arg)->push_back(chunk);
+ }
}
// Sets the appropriate tag on each chunk.
@@ -306,26 +308,33 @@ static void ClassifyAllChunks(SuspendedT
// Holds the flood fill frontier.
Frontier frontier(1);
+ ForEachChunk(CollectIgnoredCb, &frontier);
ProcessGlobalRegions(&frontier);
ProcessThreads(suspended_threads, &frontier);
ProcessRootRegions(&frontier);
FloodFillTag(&frontier, kReachable);
+
// The check here is relatively expensive, so we do this in a separate flood
// fill. That way we can skip the check for chunks that are reachable
// otherwise.
LOG_POINTERS("Processing platform-specific allocations.\n");
+ CHECK_EQ(0, frontier.size());
ProcessPlatformSpecificAllocations(&frontier);
FloodFillTag(&frontier, kReachable);
- LOG_POINTERS("Scanning ignored chunks.\n");
- CHECK_EQ(0, frontier.size());
- ForEachChunk(CollectIgnoredCb, &frontier);
- FloodFillTag(&frontier, kIgnored);
-
// Iterate over leaked chunks and mark those that are reachable from other
// leaked chunks.
LOG_POINTERS("Scanning leaked chunks.\n");
- ForEachChunk(MarkIndirectlyLeakedCb, 0 /* arg */);
+ ForEachChunk(MarkIndirectlyLeakedCb, nullptr);
+}
+
+// ForEachChunk callback. Resets the tags to pre-leak-check state.
+static void ResetTagsCb(uptr chunk, void *arg) {
+ (void)arg;
+ chunk = GetUserBegin(chunk);
+ LsanMetadata m(chunk);
+ if (m.allocated() && m.tag() != kIgnored)
+ m.set_tag(kDirectlyLeaked);
}
static void PrintStackTraceById(u32 stack_trace_id) {
@@ -371,35 +380,33 @@ static void PrintMatchedSuppressions() {
Printf("%s\n\n", line);
}
-struct DoLeakCheckParam {
+struct CheckForLeaksParam {
bool success;
LeakReport leak_report;
};
-static void DoLeakCheckCallback(const SuspendedThreadsList &suspended_threads,
- void *arg) {
- DoLeakCheckParam *param = reinterpret_cast<DoLeakCheckParam *>(arg);
+static void CheckForLeaksCallback(const SuspendedThreadsList &suspended_threads,
+ void *arg) {
+ CheckForLeaksParam *param = reinterpret_cast<CheckForLeaksParam *>(arg);
CHECK(param);
CHECK(!param->success);
ClassifyAllChunks(suspended_threads);
ForEachChunk(CollectLeaksCb, ¶m->leak_report);
+ // Clean up for subsequent leak checks. This assumes we did not overwrite any
+ // kIgnored tags.
+ ForEachChunk(ResetTagsCb, nullptr);
param->success = true;
}
-void DoLeakCheck() {
- EnsureMainThreadIDIsCorrect();
- BlockingMutexLock l(&global_mutex);
- static bool already_done;
- if (already_done) return;
- already_done = true;
+static bool CheckForLeaks() {
if (&__lsan_is_turned_off && __lsan_is_turned_off())
- return;
-
- DoLeakCheckParam param;
+ return false;
+ EnsureMainThreadIDIsCorrect();
+ CheckForLeaksParam param;
param.success = false;
LockThreadRegistry();
LockAllocator();
- DoStopTheWorld(DoLeakCheckCallback, ¶m);
+ DoStopTheWorld(CheckForLeaksCallback, ¶m);
UnlockAllocator();
UnlockThreadRegistry();
@@ -423,14 +430,33 @@ void DoLeakCheck() {
PrintMatchedSuppressions();
if (unsuppressed_count > 0) {
param.leak_report.PrintSummary();
- if (flags()->exitcode) {
- if (common_flags()->coverage)
- __sanitizer_cov_dump();
- internal__exit(flags()->exitcode);
- }
+ return true;
+ }
+ return false;
+}
+
+void DoLeakCheck() {
+ BlockingMutexLock l(&global_mutex);
+ static bool already_done;
+ if (already_done) return;
+ already_done = true;
+ bool have_leaks = CheckForLeaks();
+ if (!have_leaks) {
+ return;
+ }
+ if (flags()->exitcode) {
+ if (common_flags()->coverage)
+ __sanitizer_cov_dump();
+ internal__exit(flags()->exitcode);
}
}
+static int DoRecoverableLeakCheck() {
+ BlockingMutexLock l(&global_mutex);
+ bool have_leaks = CheckForLeaks();
+ return have_leaks ? 1 : 0;
+}
+
static Suppression *GetSuppressionForAddr(uptr addr) {
Suppression *s = nullptr;
@@ -676,6 +702,14 @@ void __lsan_do_leak_check() {
#endif // CAN_SANITIZE_LEAKS
}
+int __lsan_do_recoverable_leak_check() {
+#if CAN_SANITIZE_LEAKS
+ if (common_flags()->detect_leaks)
+ return __lsan::DoRecoverableLeakCheck();
+#endif // CAN_SANITIZE_LEAKS
+ return 0;
+}
+
#if !SANITIZER_SUPPORTS_WEAK_HOOKS
SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
int __lsan_is_turned_off() {
Modified: compiler-rt/trunk/lib/lsan/lsan_common_linux.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/lsan/lsan_common_linux.cc?rev=235728&r1=235727&r2=235728&view=diff
==============================================================================
--- compiler-rt/trunk/lib/lsan/lsan_common_linux.cc (original)
+++ compiler-rt/trunk/lib/lsan/lsan_common_linux.cc Fri Apr 24 11:53:15 2015
@@ -110,7 +110,7 @@ static void ProcessPlatformSpecificAlloc
reinterpret_cast<ProcessPlatformAllocParam *>(arg);
chunk = GetUserBegin(chunk);
LsanMetadata m(chunk);
- if (m.allocated() && m.tag() != kReachable) {
+ if (m.allocated() && m.tag() != kReachable && m.tag() != kIgnored) {
u32 stack_id = m.stack_trace_id();
uptr caller_pc = 0;
if (stack_id > 0)
Added: compiler-rt/trunk/test/lsan/TestCases/recoverable_leak_check.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/lsan/TestCases/recoverable_leak_check.cc?rev=235728&view=auto
==============================================================================
--- compiler-rt/trunk/test/lsan/TestCases/recoverable_leak_check.cc (added)
+++ compiler-rt/trunk/test/lsan/TestCases/recoverable_leak_check.cc Fri Apr 24 11:53:15 2015
@@ -0,0 +1,32 @@
+// Test for on-demand leak checking.
+// RUN: LSAN_BASE="use_stacks=0:use_registers=0"
+// RUN: %clangxx_lsan %s -o %t
+// RUN: LSAN_OPTIONS=$LSAN_BASE %run %t foo 2>&1 | FileCheck %s
+// RUN: LSAN_OPTIONS=$LSAN_BASE %run %t 2>&1 | FileCheck %s
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sanitizer/lsan_interface.h>
+
+void *p;
+
+int main(int argc, char *argv[]) {
+ p = malloc(23);
+
+ assert(__lsan_do_recoverable_leak_check() == 0);
+
+ fprintf(stderr, "Test alloc: %p.\n", malloc(1337));
+// CHECK: Test alloc:
+
+ assert(__lsan_do_recoverable_leak_check() == 1);
+// CHECK: SUMMARY: {{(Leak|Address)}}Sanitizer: 1337 byte
+
+ // Test that we correctly reset chunk tags.
+ p = 0;
+ assert(__lsan_do_recoverable_leak_check() == 1);
+// CHECK: SUMMARY: {{(Leak|Address)}}Sanitizer: 1360 byte
+
+ _exit(0);
+}
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