Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 1 | //=-- lsan_common_linux.cc ------------------------------------------------===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // This file is a part of LeakSanitizer. |
| 11 | // Implementation of common leak checking functionality. Linux-specific code. |
| 12 | // |
| 13 | //===----------------------------------------------------------------------===// |
| 14 | |
| 15 | #include "sanitizer_common/sanitizer_platform.h" |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 16 | #include "lsan_common.h" |
| 17 | |
Sergey Matveev | 9bdf780 | 2013-05-21 14:12:11 +0000 | [diff] [blame] | 18 | #if CAN_SANITIZE_LEAKS && SANITIZER_LINUX |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 19 | #include <link.h> |
| 20 | |
| 21 | #include "sanitizer_common/sanitizer_common.h" |
Stephen Hines | 2d1fdb2 | 2014-05-28 23:58:16 -0700 | [diff] [blame] | 22 | #include "sanitizer_common/sanitizer_flags.h" |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 23 | #include "sanitizer_common/sanitizer_linux.h" |
| 24 | #include "sanitizer_common/sanitizer_stackdepot.h" |
| 25 | |
| 26 | namespace __lsan { |
| 27 | |
| 28 | static const char kLinkerName[] = "ld"; |
Pirama Arumuga Nainar | c58a436 | 2016-09-19 23:00:23 -0700 | [diff] [blame] | 29 | |
| 30 | static char linker_placeholder[sizeof(LoadedModule)] ALIGNED(64); |
Pirama Arumuga Nainar | 799172d | 2016-03-03 15:50:30 -0800 | [diff] [blame] | 31 | static LoadedModule *linker = nullptr; |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 32 | |
| 33 | static bool IsLinker(const char* full_name) { |
| 34 | return LibraryNameIs(full_name, kLinkerName); |
| 35 | } |
| 36 | |
| 37 | void InitializePlatformSpecificModules() { |
Pirama Arumuga Nainar | c58a436 | 2016-09-19 23:00:23 -0700 | [diff] [blame] | 38 | ListOfModules modules; |
| 39 | modules.init(); |
| 40 | for (LoadedModule &module : modules) { |
| 41 | if (!IsLinker(module.full_name())) continue; |
| 42 | if (linker == nullptr) { |
| 43 | linker = reinterpret_cast<LoadedModule *>(linker_placeholder); |
| 44 | *linker = module; |
| 45 | module = LoadedModule(); |
| 46 | } else { |
| 47 | VReport(1, "LeakSanitizer: Multiple modules match \"%s\". " |
| 48 | "TLS will not be handled correctly.\n", kLinkerName); |
| 49 | linker->clear(); |
| 50 | linker = nullptr; |
| 51 | return; |
| 52 | } |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 53 | } |
Pirama Arumuga Nainar | c58a436 | 2016-09-19 23:00:23 -0700 | [diff] [blame] | 54 | VReport(1, "LeakSanitizer: Dynamic linker not found. " |
| 55 | "TLS will not be handled correctly.\n"); |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 56 | } |
| 57 | |
| 58 | static int ProcessGlobalRegionsCallback(struct dl_phdr_info *info, size_t size, |
| 59 | void *data) { |
Sergey Matveev | ac78d00 | 2013-06-24 08:34:50 +0000 | [diff] [blame] | 60 | Frontier *frontier = reinterpret_cast<Frontier *>(data); |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 61 | for (uptr j = 0; j < info->dlpi_phnum; j++) { |
| 62 | const ElfW(Phdr) *phdr = &(info->dlpi_phdr[j]); |
| 63 | // We're looking for .data and .bss sections, which reside in writeable, |
| 64 | // loadable segments. |
| 65 | if (!(phdr->p_flags & PF_W) || (phdr->p_type != PT_LOAD) || |
| 66 | (phdr->p_memsz == 0)) |
| 67 | continue; |
| 68 | uptr begin = info->dlpi_addr + phdr->p_vaddr; |
| 69 | uptr end = begin + phdr->p_memsz; |
| 70 | uptr allocator_begin = 0, allocator_end = 0; |
| 71 | GetAllocatorGlobalRange(&allocator_begin, &allocator_end); |
| 72 | if (begin <= allocator_begin && allocator_begin < end) { |
| 73 | CHECK_LE(allocator_begin, allocator_end); |
| 74 | CHECK_LT(allocator_end, end); |
| 75 | if (begin < allocator_begin) |
| 76 | ScanRangeForPointers(begin, allocator_begin, frontier, "GLOBAL", |
| 77 | kReachable); |
| 78 | if (allocator_end < end) |
| 79 | ScanRangeForPointers(allocator_end, end, frontier, "GLOBAL", |
| 80 | kReachable); |
| 81 | } else { |
| 82 | ScanRangeForPointers(begin, end, frontier, "GLOBAL", kReachable); |
| 83 | } |
| 84 | } |
| 85 | return 0; |
| 86 | } |
| 87 | |
Sergey Matveev | ac78d00 | 2013-06-24 08:34:50 +0000 | [diff] [blame] | 88 | // Scans global variables for heap pointers. |
Alexey Samsonov | dbeb48d | 2013-06-14 10:07:56 +0000 | [diff] [blame] | 89 | void ProcessGlobalRegions(Frontier *frontier) { |
Stephen Hines | 2d1fdb2 | 2014-05-28 23:58:16 -0700 | [diff] [blame] | 90 | if (!flags()->use_globals) return; |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 91 | dl_iterate_phdr(ProcessGlobalRegionsCallback, frontier); |
| 92 | } |
| 93 | |
Sergey Matveev | 384a448 | 2013-08-26 13:24:43 +0000 | [diff] [blame] | 94 | static uptr GetCallerPC(u32 stack_id, StackDepotReverseMap *map) { |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 95 | CHECK(stack_id); |
Stephen Hines | 6d18623 | 2014-11-26 17:56:19 -0800 | [diff] [blame] | 96 | StackTrace stack = map->Get(stack_id); |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 97 | // The top frame is our malloc/calloc/etc. The next frame is the caller. |
Stephen Hines | 6d18623 | 2014-11-26 17:56:19 -0800 | [diff] [blame] | 98 | if (stack.size >= 2) |
| 99 | return stack.trace[1]; |
Sergey Matveev | 0550a3f | 2013-06-06 14:19:36 +0000 | [diff] [blame] | 100 | return 0; |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 101 | } |
| 102 | |
Sergey Matveev | 384a448 | 2013-08-26 13:24:43 +0000 | [diff] [blame] | 103 | struct ProcessPlatformAllocParam { |
| 104 | Frontier *frontier; |
| 105 | StackDepotReverseMap *stack_depot_reverse_map; |
Pirama Arumuga Nainar | c58a436 | 2016-09-19 23:00:23 -0700 | [diff] [blame] | 106 | bool skip_linker_allocations; |
Sergey Matveev | 384a448 | 2013-08-26 13:24:43 +0000 | [diff] [blame] | 107 | }; |
| 108 | |
Sergey Matveev | ac78d00 | 2013-06-24 08:34:50 +0000 | [diff] [blame] | 109 | // ForEachChunk callback. Identifies unreachable chunks which must be treated as |
| 110 | // reachable. Marks them as reachable and adds them to the frontier. |
| 111 | static void ProcessPlatformSpecificAllocationsCb(uptr chunk, void *arg) { |
| 112 | CHECK(arg); |
Sergey Matveev | 384a448 | 2013-08-26 13:24:43 +0000 | [diff] [blame] | 113 | ProcessPlatformAllocParam *param = |
| 114 | reinterpret_cast<ProcessPlatformAllocParam *>(arg); |
Sergey Matveev | ac78d00 | 2013-06-24 08:34:50 +0000 | [diff] [blame] | 115 | chunk = GetUserBegin(chunk); |
| 116 | LsanMetadata m(chunk); |
Pirama Arumuga Nainar | cdce50b | 2015-07-01 12:26:56 -0700 | [diff] [blame] | 117 | if (m.allocated() && m.tag() != kReachable && m.tag() != kIgnored) { |
Evgeniy Stepanov | 96a575f | 2013-09-12 08:16:28 +0000 | [diff] [blame] | 118 | u32 stack_id = m.stack_trace_id(); |
Alexey Samsonov | 2946f13 | 2013-09-30 10:57:56 +0000 | [diff] [blame] | 119 | uptr caller_pc = 0; |
| 120 | if (stack_id > 0) |
| 121 | caller_pc = GetCallerPC(stack_id, param->stack_depot_reverse_map); |
| 122 | // If caller_pc is unknown, this chunk may be allocated in a coroutine. Mark |
| 123 | // it as reachable, as we can't properly report its allocation stack anyway. |
Pirama Arumuga Nainar | c58a436 | 2016-09-19 23:00:23 -0700 | [diff] [blame] | 124 | if (caller_pc == 0 || (param->skip_linker_allocations && |
| 125 | linker->containsAddress(caller_pc))) { |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 126 | m.set_tag(kReachable); |
Sergey Matveev | 384a448 | 2013-08-26 13:24:43 +0000 | [diff] [blame] | 127 | param->frontier->push_back(chunk); |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 128 | } |
| 129 | } |
| 130 | } |
| 131 | |
Sergey Matveev | ac78d00 | 2013-06-24 08:34:50 +0000 | [diff] [blame] | 132 | // Handles dynamically allocated TLS blocks by treating all chunks allocated |
| 133 | // from ld-linux.so as reachable. |
Stephen Hines | 2d1fdb2 | 2014-05-28 23:58:16 -0700 | [diff] [blame] | 134 | // Dynamic TLS blocks contain the TLS variables of dynamically loaded modules. |
| 135 | // They are allocated with a __libc_memalign() call in allocate_and_init() |
| 136 | // (elf/dl-tls.c). Glibc won't tell us the address ranges occupied by those |
| 137 | // blocks, but we can make sure they come from our own allocator by intercepting |
| 138 | // __libc_memalign(). On top of that, there is no easy way to reach them. Their |
| 139 | // addresses are stored in a dynamically allocated array (the DTV) which is |
| 140 | // referenced from the static TLS. Unfortunately, we can't just rely on the DTV |
| 141 | // being reachable from the static TLS, and the dynamic TLS being reachable from |
| 142 | // the DTV. This is because the initial DTV is allocated before our interception |
| 143 | // mechanism kicks in, and thus we don't recognize it as allocated memory. We |
| 144 | // can't special-case it either, since we don't know its size. |
| 145 | // Our solution is to include in the root set all allocations made from |
| 146 | // ld-linux.so (which is where allocate_and_init() is implemented). This is |
| 147 | // guaranteed to include all dynamic TLS blocks (and possibly other allocations |
| 148 | // which we don't care about). |
Alexey Samsonov | dbeb48d | 2013-06-14 10:07:56 +0000 | [diff] [blame] | 149 | void ProcessPlatformSpecificAllocations(Frontier *frontier) { |
Sergey Matveev | 384a448 | 2013-08-26 13:24:43 +0000 | [diff] [blame] | 150 | StackDepotReverseMap stack_depot_reverse_map; |
Pirama Arumuga Nainar | c58a436 | 2016-09-19 23:00:23 -0700 | [diff] [blame] | 151 | ProcessPlatformAllocParam arg; |
| 152 | arg.frontier = frontier; |
| 153 | arg.stack_depot_reverse_map = &stack_depot_reverse_map; |
| 154 | arg.skip_linker_allocations = |
| 155 | flags()->use_tls && flags()->use_ld_allocations && linker != nullptr; |
Sergey Matveev | 384a448 | 2013-08-26 13:24:43 +0000 | [diff] [blame] | 156 | ForEachChunk(ProcessPlatformSpecificAllocationsCb, &arg); |
Sergey Matveev | ab0f744 | 2013-05-20 11:06:50 +0000 | [diff] [blame] | 157 | } |
| 158 | |
Stephen Hines | 86277eb | 2015-03-23 12:06:32 -0700 | [diff] [blame] | 159 | struct DoStopTheWorldParam { |
| 160 | StopTheWorldCallback callback; |
| 161 | void *argument; |
| 162 | }; |
| 163 | |
| 164 | static int DoStopTheWorldCallback(struct dl_phdr_info *info, size_t size, |
| 165 | void *data) { |
| 166 | DoStopTheWorldParam *param = reinterpret_cast<DoStopTheWorldParam *>(data); |
| 167 | StopTheWorld(param->callback, param->argument); |
| 168 | return 1; |
| 169 | } |
| 170 | |
| 171 | // LSan calls dl_iterate_phdr() from the tracer task. This may deadlock: if one |
| 172 | // of the threads is frozen while holding the libdl lock, the tracer will hang |
| 173 | // in dl_iterate_phdr() forever. |
| 174 | // Luckily, (a) the lock is reentrant and (b) libc can't distinguish between the |
| 175 | // tracer task and the thread that spawned it. Thus, if we run the tracer task |
| 176 | // while holding the libdl lock in the parent thread, we can safely reenter it |
| 177 | // in the tracer. The solution is to run stoptheworld from a dl_iterate_phdr() |
| 178 | // callback in the parent thread. |
| 179 | void DoStopTheWorld(StopTheWorldCallback callback, void *argument) { |
| 180 | DoStopTheWorldParam param = {callback, argument}; |
| 181 | dl_iterate_phdr(DoStopTheWorldCallback, ¶m); |
| 182 | } |
| 183 | |
Pirama Arumuga Nainar | 799172d | 2016-03-03 15:50:30 -0800 | [diff] [blame] | 184 | } // namespace __lsan |
| 185 | |
| 186 | #endif // CAN_SANITIZE_LEAKS && SANITIZER_LINUX |