Don't try to use pidfd_getfd via a process that is already dying.
Resolves #3436
diff --git a/src/AutoRemoteSyscalls.cc b/src/AutoRemoteSyscalls.cc
index f69c0ec..0398096 100644
--- a/src/AutoRemoteSyscalls.cc
+++ b/src/AutoRemoteSyscalls.cc
@@ -632,7 +632,7 @@
static Task* thread_group_leader_for_fds(Task* t) {
for (Task* tt : t->fd_table()->task_set()) {
- if (tt->tgid() == tt->rec_tid) {
+ if (tt->tgid() == tt->rec_tid && !tt->is_dying()) {
return tt;
}
}
@@ -641,8 +641,9 @@
template <typename Arch> ScopedFd AutoRemoteSyscalls::retrieve_fd_arch(int fd) {
ScopedFd ret;
- // Try to use pidfd_getfd to get the fd without round-tripping to the tracee
if (!pid_fd.is_open()) {
+ // Try to use pidfd_getfd to get the fd without round-tripping to the tracee.
+ // pidfd_getfd requires a threadgroup leader, so find one if we can.
Task* tg_leader_for_fds = thread_group_leader_for_fds(t);
if (tg_leader_for_fds) {
pid_fd = ScopedFd(::syscall(NativeArch::pidfd_open, tg_leader_for_fds->tid, 0));
