Skip to content

Fix use-after-free crash in getBrokerConsumerStatsAsync when connection is closed #537

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
dragonls wants to merge 1 commit into from
+11 −11
Closed

Fix use-after-free crash in getBrokerConsumerStatsAsync when connection is closed #537

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
22 changes: 11 additions & 11 deletions lib/MultiTopicsConsumerImpl.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -850,17 +850,17 @@ void MultiTopicsConsumerImpl::getBrokerConsumerStatsAsync(const BrokerConsumerSt
LatchPtr latchPtr = std::make_shared<Latch>(numberTopicPartitions_->load());
lock.unlock();

size_t i = 0;
consumers_.forEachValue([this, &latchPtr, &statsPtr, &i, callback](const ConsumerImplPtr& consumer) {
size_t index = i++;
auto weakSelf = weak_from_this();
consumer->getBrokerConsumerStatsAsync([this, weakSelf, latchPtr, statsPtr, index, callback](
Result result, const BrokerConsumerStats& stats) {
auto self = weakSelf.lock();
if (self) {
handleGetConsumerStats(result, stats, latchPtr, statsPtr, index, callback);
}
});
auto indexPtr = std::make_shared<std::atomic<size_t>>(0);
auto weakSelf = weak_from_this();
consumers_.forEachValue([weakSelf, latchPtr, statsPtr, indexPtr, callback](const ConsumerImplPtr& consumer) {
Copy link
Contributor

@BewareMyPower BewareMyPower Feb 4, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The callback of forEachValue is immediately executed in the current method.

pulsar-client-cpp/lib/SynchronizedHashMap.h

Lines 95 to 99 in 0b893a1

void forEachValue(ValueFunc&& each) {
Lock lock{mutex_};
for (auto&& kv : data_) {
each(kv.second);
}

so I believe this patch does not fix the actual issue

Copy link
Author

@dragonls dragonls Feb 4, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yes, but in consumers_.forEachValue, it also calls consumer->getBrokerConsumerStatsAsync, which passed the weakSelf into the callback. The callback is executed later.

Copy link
Contributor

@BewareMyPower BewareMyPower Feb 4, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The lambda of getBrokerConsumerStatsAsync captures all variables by value:

consumer->getBrokerConsumerStatsAsync([this, weakSelf, latchPtr, statsPtr, index, callback](

size_t index = indexPtr->fetch_add(1);
consumer->getBrokerConsumerStatsAsync([weakSelf, latchPtr, statsPtr, index, callback](
Result result, const BrokerConsumerStats& stats) {
auto self = weakSelf.lock();
if (self) {
self->handleGetConsumerStats(result, stats, latchPtr, statsPtr, index, callback);
}
});
});
}

Expand Down