mirror/naiveproxy
1
0
Fork 0
mirror of https://github.com/klzgrad/naiveproxy.git synced 2025-04-03 13:53:37 +03:00
Code Issues Projects Releases Wiki Activity

Proper fix of pthread_atfork deadlock in Musl

Browse source 
PartitionRoot::EnableThreadCacheIfSupported()
  ::partition_alloc::internal::ScopedGuard guard{lock_};
  ThreadCache::Create(this);
    ThreadCache::ThreadCache()
      PlatformThread::CurrentId()
        InitAtFork::InitAtFork()
          pthread_atfork()
            malloc()
              ShimMalloc()
                PartitionAllocFunctionsInternal::Malloc()
                  PartitionRoot::AllocInternal()
                    PartitionRoot::AllocInternalNoHooks()
                      PartitionRoot::RawAlloc()
                        ::partition_alloc::internal::ScopedGuard guard{internal::PartitionRootLock(this)};
This commit is contained in:
klzgrad 2025-02-09 13:06:22 +08:00
parent eac1a955ce
commit c44bf60e04
2 changed files with 39 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

19
src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/threading/platform_thread_posix.cc
View file

@ -28,6 +28,10 @@
#include <zircon/process.h>
#endif
#if defined(__MUSL__)
#include "partition_alloc/shim/allocator_shim.h"
#endif
namespace partition_alloc::internal::base {
#if PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)
@ -59,8 +63,21 @@ thread_local bool g_is_main_thread = true;
class InitAtFork {
public:
InitAtFork() {
#if !defined(__MUSL__)
#if defined(__MUSL__)
allocator_shim::AllocatorDispatch d =
*allocator_shim::GetAllocatorDispatchChainHeadForTesting();
d.alloc_function = +[](size_t size, void*) -> void* {
// The size of the scratch fits struct atfork_funcs in Musl pthread_atfork.c.
static char scratch[5 * sizeof(void*)];
return size != sizeof(scratch) ? nullptr : scratch;
};
allocator_shim::InsertAllocatorDispatch(&d);
#endif
pthread_atfork(nullptr, nullptr, internal::InvalidateTidCache);
#if defined(__MUSL__)
allocator_shim::RemoveAllocatorDispatchForTesting(&d);
#endif
}
};

26
src/base/allocator/partition_allocator/src/partition_alloc/partition_root.cc
View file

@ -51,6 +51,10 @@
#endif // PA_CONFIG(ENABLE_SHADOW_METADATA)
#endif // PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)
#if defined(__MUSL__)
#include "partition_alloc/shim/allocator_shim.h"
#endif
namespace partition_alloc::internal {
#if PA_BUILDFLAG(RECORD_ALLOC_INFO)
@ -297,11 +301,7 @@ void PartitionAllocMallocInitOnce() {
return;
}
#if defined(__MUSL__)
static_cast<void>(BeforeForkInParent);
static_cast<void>(AfterForkInParent);
static_cast<void>(AfterForkInChild);
#elif PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)
#if PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)
// When fork() is called, only the current thread continues to execute in the
// child process. If the lock is held, but *not* by this thread when fork() is
// called, we have a deadlock.
@ -323,9 +323,25 @@ void PartitionAllocMallocInitOnce() {
// However, no perfect solution really exists to make threads + fork()
// cooperate, but deadlocks are real (and fork() is used in DEATH_TEST()s),
// and other malloc() implementations use the same techniques.
#if defined(__MUSL__)
allocator_shim::AllocatorDispatch d =
*allocator_shim::GetAllocatorDispatchChainHeadForTesting();
d.alloc_function = +[](size_t size, void*) -> void* {
// The size of the scratch fits struct atfork_funcs in Musl pthread_atfork.c.
static char scratch[5 * sizeof(void*)];
return size != sizeof(scratch) ? nullptr : scratch;
};
allocator_shim::InsertAllocatorDispatch(&d);
#endif
int err =
pthread_atfork(BeforeForkInParent, AfterForkInParent, AfterForkInChild);
PA_CHECK(err == 0);
#if defined(__MUSL__)
allocator_shim::RemoveAllocatorDispatchForTesting(&d);
#endif
#endif // PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)
}