1 //=-- lsan_common_linux.cc ------------------------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file is a part of LeakSanitizer.
11 // Implementation of common leak checking functionality. Linux-specific code.
13 //===----------------------------------------------------------------------===//
15 #include "sanitizer_common/sanitizer_platform.h"
16 #include "lsan_common.h"
18 #if CAN_SANITIZE_LEAKS && SANITIZER_LINUX
21 #include "sanitizer_common/sanitizer_common.h"
22 #include "sanitizer_common/sanitizer_flags.h"
23 #include "sanitizer_common/sanitizer_getauxval.h"
24 #include "sanitizer_common/sanitizer_linux.h"
25 #include "sanitizer_common/sanitizer_stackdepot.h"
29 static const char kLinkerName[] = "ld";
31 static char linker_placeholder[sizeof(LoadedModule)] ALIGNED(64);
32 static LoadedModule *linker = nullptr;
34 static bool IsLinker(const LoadedModule& module) {
35 #if SANITIZER_USE_GETAUXVAL
36 return module.base_address() == getauxval(AT_BASE);
38 return LibraryNameIs(module.full_name(), kLinkerName);
39 #endif // SANITIZER_USE_GETAUXVAL
42 __attribute__((tls_model("initial-exec")))
43 THREADLOCAL int disable_counter;
44 bool DisabledInThisThread() { return disable_counter > 0; }
45 void DisableInThisThread() { disable_counter++; }
46 void EnableInThisThread() {
47 if (disable_counter == 0) {
48 DisableCounterUnderflow();
53 void InitializePlatformSpecificModules() {
54 ListOfModules modules;
56 for (LoadedModule &module : modules) {
57 if (!IsLinker(module))
59 if (linker == nullptr) {
60 linker = reinterpret_cast<LoadedModule *>(linker_placeholder);
62 module = LoadedModule();
64 VReport(1, "LeakSanitizer: Multiple modules match \"%s\". "
65 "TLS and other allocations originating from linker might be "
66 "falsely reported as leaks.\n", kLinkerName);
72 if (linker == nullptr) {
73 VReport(1, "LeakSanitizer: Dynamic linker not found. TLS and other "
74 "allocations originating from linker might be falsely reported "
79 static int ProcessGlobalRegionsCallback(struct dl_phdr_info *info, size_t size,
81 Frontier *frontier = reinterpret_cast<Frontier *>(data);
82 for (uptr j = 0; j < info->dlpi_phnum; j++) {
83 const ElfW(Phdr) *phdr = &(info->dlpi_phdr[j]);
84 // We're looking for .data and .bss sections, which reside in writeable,
86 if (!(phdr->p_flags & PF_W) || (phdr->p_type != PT_LOAD) ||
89 uptr begin = info->dlpi_addr + phdr->p_vaddr;
90 uptr end = begin + phdr->p_memsz;
91 ScanGlobalRange(begin, end, frontier);
96 // Scans global variables for heap pointers.
97 void ProcessGlobalRegions(Frontier *frontier) {
98 if (!flags()->use_globals) return;
99 dl_iterate_phdr(ProcessGlobalRegionsCallback, frontier);
102 LoadedModule *GetLinker() { return linker; }
104 void ProcessPlatformSpecificAllocations(Frontier *frontier) {}
106 struct DoStopTheWorldParam {
107 StopTheWorldCallback callback;
111 // While calling Die() here is undefined behavior and can potentially
112 // cause race conditions, it isn't possible to intercept exit on linux,
113 // so we have no choice but to call Die() from the atexit handler.
115 if (common_flags()->exitcode) Die();
118 static int DoStopTheWorldCallback(struct dl_phdr_info *info, size_t size,
120 DoStopTheWorldParam *param = reinterpret_cast<DoStopTheWorldParam *>(data);
121 StopTheWorld(param->callback, param->argument);
125 // LSan calls dl_iterate_phdr() from the tracer task. This may deadlock: if one
126 // of the threads is frozen while holding the libdl lock, the tracer will hang
127 // in dl_iterate_phdr() forever.
128 // Luckily, (a) the lock is reentrant and (b) libc can't distinguish between the
129 // tracer task and the thread that spawned it. Thus, if we run the tracer task
130 // while holding the libdl lock in the parent thread, we can safely reenter it
131 // in the tracer. The solution is to run stoptheworld from a dl_iterate_phdr()
132 // callback in the parent thread.
133 void DoStopTheWorld(StopTheWorldCallback callback, void *argument) {
134 DoStopTheWorldParam param = {callback, argument};
135 dl_iterate_phdr(DoStopTheWorldCallback, ¶m);
138 } // namespace __lsan
140 #endif // CAN_SANITIZE_LEAKS && SANITIZER_LINUX