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Kernel: Fix kernel null deref on process crash during join_thread()

The join_thread() syscall is not supposed to be interruptible by
signals, but it was. And since the process death mechanism piggybacked
on signal interrupts, it was possible to interrupt a pthread_join() by
killing the process that was doing it, leading to confusing due to some
assumptions being made by Thread::finalize() for threads that have a
pending joiner.

This patch fixes the issue by making "interrupted by death" a distinct
block result separate from "interrupted by signal". Then we handle that
state in join_thread() and tidy things up so that thread finalization
doesn't get confused by the pending joiner being gone.

Test: Tests/Kernel/null-deref-crash-during-pthread_join.cpp
This commit is contained in:
Andreas Kling 2020-01-10 19:15:01 +01:00
parent 6a529ea425
commit 8c5cd97b45
7 changed files with 55 additions and 20 deletions

View file

@ -341,7 +341,7 @@ KResult TCPSocket::protocol_connect(FileDescription& description, ShouldBlock sh
m_direction = Direction::Outgoing;
if (should_block == ShouldBlock::Yes) {
if (current->block<Thread::ConnectBlocker>(description) == Thread::BlockResult::InterruptedBySignal)
if (current->block<Thread::ConnectBlocker>(description) != Thread::BlockResult::WokeNormally)
return KResult(-EINTR);
ASSERT(setup_state() == SetupState::Completed);
if (has_error()) {