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Diffstat (limited to 'absl/debugging/internal/address_is_readable.cc')
-rw-r--r--absl/debugging/internal/address_is_readable.cc9
1 files changed, 5 insertions, 4 deletions
diff --git a/absl/debugging/internal/address_is_readable.cc b/absl/debugging/internal/address_is_readable.cc
index 65376063..329c285f 100644
--- a/absl/debugging/internal/address_is_readable.cc
+++ b/absl/debugging/internal/address_is_readable.cc
@@ -68,6 +68,7 @@ static void Unpack(uint64_t x, int *pid, int *read_fd, int *write_fd) {
// unimplemented.
// This is a namespace-scoped variable for correct zero-initialization.
static std::atomic<uint64_t> pid_and_fds; // initially 0, an invalid pid.
+
bool AddressIsReadable(const void *addr) {
absl::base_internal::ErrnoSaver errno_saver;
// We test whether a byte is readable by using write(). Normally, this would
@@ -86,7 +87,7 @@ bool AddressIsReadable(const void *addr) {
int pid;
int read_fd;
int write_fd;
- uint64_t local_pid_and_fds = pid_and_fds.load(std::memory_order_relaxed);
+ uint64_t local_pid_and_fds = pid_and_fds.load(std::memory_order_acquire);
Unpack(local_pid_and_fds, &pid, &read_fd, &write_fd);
while (current_pid != pid) {
int p[2];
@@ -98,13 +99,13 @@ bool AddressIsReadable(const void *addr) {
fcntl(p[1], F_SETFD, FD_CLOEXEC);
uint64_t new_pid_and_fds = Pack(current_pid, p[0], p[1]);
if (pid_and_fds.compare_exchange_strong(
- local_pid_and_fds, new_pid_and_fds, std::memory_order_relaxed,
+ local_pid_and_fds, new_pid_and_fds, std::memory_order_release,
std::memory_order_relaxed)) {
local_pid_and_fds = new_pid_and_fds; // fds exposed to other threads
} else { // fds not exposed to other threads; we can close them.
close(p[0]);
close(p[1]);
- local_pid_and_fds = pid_and_fds.load(std::memory_order_relaxed);
+ local_pid_and_fds = pid_and_fds.load(std::memory_order_acquire);
}
Unpack(local_pid_and_fds, &pid, &read_fd, &write_fd);
}
@@ -124,7 +125,7 @@ bool AddressIsReadable(const void *addr) {
// If pid_and_fds contains the problematic file descriptors we just used,
// this call will forget them, and the loop will try again.
pid_and_fds.compare_exchange_strong(local_pid_and_fds, 0,
- std::memory_order_relaxed,
+ std::memory_order_release,
std::memory_order_relaxed);
}
} while (errno == EBADF);