From 44f9376347d7fd4e1ef85dfd284e1549c42ecb81 Mon Sep 17 00:00:00 2001 From: Alex Shlyapnikov Date: Thu, 5 Oct 2017 21:38:33 +0000 Subject: [PATCH] [LSan] Detect dynamic loader by its base address. Summary: Relanding D33859, which was reverted because it has "broken LOTS of ARM/AArch64 bots for two days". If it breaks something again, please provide some pointers to broken bots, not just revert it, otherwise it's very hard to reason what's wrong with this commit. Whenever possible (Linux + glibc 2.16+), detect dynamic loader module by its base address, not by the module name matching. The current name matching approach fails on some configurations. Reviewers: eugenis Subscribers: aemerson, kubamracek, kristof.beyls, llvm-commits Differential Revision: https://reviews.llvm.org/D38600 llvm-svn: 315024 --- compiler-rt/lib/lsan/lsan_common.cc | 5 ++-- compiler-rt/lib/lsan/lsan_common_linux.cc | 23 ++++++++++++++----- .../lib/sanitizer_common/sanitizer_linux.cc | 10 -------- .../lib/sanitizer_common/sanitizer_platform.h | 9 ++++++++ 4 files changed, 29 insertions(+), 18 deletions(-) diff --git a/compiler-rt/lib/lsan/lsan_common.cc b/compiler-rt/lib/lsan/lsan_common.cc index 622aae7342c5..651bbe1f3709 100644 --- a/compiler-rt/lib/lsan/lsan_common.cc +++ b/compiler-rt/lib/lsan/lsan_common.cc @@ -411,8 +411,9 @@ static void MarkInvalidPCCb(uptr chunk, void *arg) { } } -// On Linux, handles dynamically allocated TLS blocks by treating all chunks -// allocated from ld-linux.so as reachable. +// On Linux, treats all chunks allocated from ld-linux.so as reachable, which +// covers dynamically allocated TLS blocks, internal dynamic loader's loaded +// modules accounting etc. // Dynamic TLS blocks contain the TLS variables of dynamically loaded modules. // They are allocated with a __libc_memalign() call in allocate_and_init() // (elf/dl-tls.c). Glibc won't tell us the address ranges occupied by those diff --git a/compiler-rt/lib/lsan/lsan_common_linux.cc b/compiler-rt/lib/lsan/lsan_common_linux.cc index 5042c7b3ada5..5acff0b2d223 100644 --- a/compiler-rt/lib/lsan/lsan_common_linux.cc +++ b/compiler-rt/lib/lsan/lsan_common_linux.cc @@ -23,6 +23,10 @@ #include "sanitizer_common/sanitizer_linux.h" #include "sanitizer_common/sanitizer_stackdepot.h" +#if SANITIZER_USE_GETAUXVAL +#include +#endif // SANITIZER_USE_GETAUXVAL + namespace __lsan { static const char kLinkerName[] = "ld"; @@ -30,8 +34,12 @@ static const char kLinkerName[] = "ld"; static char linker_placeholder[sizeof(LoadedModule)] ALIGNED(64); static LoadedModule *linker = nullptr; -static bool IsLinker(const char* full_name) { - return LibraryNameIs(full_name, kLinkerName); +static bool IsLinker(const LoadedModule& module) { +#if SANITIZER_USE_GETAUXVAL + return module.base_address() == getauxval(AT_BASE); +#else + return LibraryNameIs(module.full_name(), kLinkerName); +#endif // SANITIZER_USE_GETAUXVAL } __attribute__((tls_model("initial-exec"))) @@ -49,22 +57,25 @@ void InitializePlatformSpecificModules() { ListOfModules modules; modules.init(); for (LoadedModule &module : modules) { - if (!IsLinker(module.full_name())) continue; + if (!IsLinker(module)) + continue; if (linker == nullptr) { linker = reinterpret_cast(linker_placeholder); *linker = module; module = LoadedModule(); } else { VReport(1, "LeakSanitizer: Multiple modules match \"%s\". " - "TLS will not be handled correctly.\n", kLinkerName); + "TLS and other allocations originating from linker might be " + "falsely reported as leaks.\n", kLinkerName); linker->clear(); linker = nullptr; return; } } if (linker == nullptr) { - VReport(1, "LeakSanitizer: Dynamic linker not found. " - "TLS will not be handled correctly.\n"); + VReport(1, "LeakSanitizer: Dynamic linker not found. TLS and other " + "allocations originating from linker might be falsely reported " + "as leaks.\n"); } } diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cc b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cc index 48c53d46df72..f239b4fbaabf 100644 --- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cc +++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cc @@ -93,16 +93,6 @@ extern char **environ; // provided by crt1 #include #endif -#ifndef __GLIBC_PREREQ -#define __GLIBC_PREREQ(x, y) 0 -#endif - -#if SANITIZER_LINUX && __GLIBC_PREREQ(2, 16) -# define SANITIZER_USE_GETAUXVAL 1 -#else -# define SANITIZER_USE_GETAUXVAL 0 -#endif - #if SANITIZER_USE_GETAUXVAL #include #endif diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform.h index 81d9164c3129..763d6e01b275 100644 --- a/compiler-rt/lib/sanitizer_common/sanitizer_platform.h +++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform.h @@ -282,5 +282,14 @@ # define SANITIZER_SUPPRESS_LEAK_ON_PTHREAD_EXIT 0 #endif +#ifndef __GLIBC_PREREQ +#define __GLIBC_PREREQ(x, y) 0 +#endif + +#if SANITIZER_LINUX && __GLIBC_PREREQ(2, 16) +# define SANITIZER_USE_GETAUXVAL 1 +#else +# define SANITIZER_USE_GETAUXVAL 0 +#endif #endif // SANITIZER_PLATFORM_H -- 2.34.1