Original patch contributed by andrey.semashev@gmail.com.
In PhysicalSocketServer::WaitEpoll(), the loop verifies that the
signalled dispatcher is in dispatchers_ set. It does so by looking up
the dispatcher pointer in the set. This is vulnerable to the ABA
problem because one dispatcher may be removed and destroyed and another
created and added with the same address before epoll reports an event
for the old dispatcher. The same issue exists for other Wait
implementations, if a dispatcher is removed and a new one added with
the same socket handle is the old.
This is avoided by using a 64-bit key for looking up the dispatcher
in the set. The key is set from a running counter which gets incremented
when a dispatcher is added to the set, so even if the same dispatcher
pointer is added, removed and added again, the key value will be
different.
This changes the storage of dispatchers_ from a set to a flat_hash_map,
which uses a bit more memory but has faster lookup (O(1) as opposed to
O(log n)).
Bug: webrtc:11124
Change-Id: I6d206e1a367b58ba971edca9b48af7664384b797
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/181027
Commit-Queue: Taylor <deadbeef@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32019}
Semi-automatically created with:
git grep -l " testing::" | xargs sed -i "s/ testing::/ ::testing::/g"
git grep -l "(testing::" | xargs sed -i "s/(testing::/(::testing::/g"
git cl format
After this, two .cc files failed to compile and I have fixed them
manually.
Bug: webrtc:10523
Change-Id: I4741d3bcedc831b6c5fdc04485678617eb4ce031
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/132018
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27526}
