github/kata-containers
1
0
Fork 2
mirror of https://github.com/kata-containers/kata-containers.git synced 2025-09-16 06:18:58 +00:00
Code Issues Projects Releases Wiki Activity

agent: Fix a race condition in passfd_io.rs

Browse Source 
There is a race condition in agent HVSOCK_STREAMS hashmap, where a
stream may be taken before it is inserted into the hashmap. This patch
add simple retry logic to the stream consumer to alleviate this issue.

Fixes: #6714
Signed-off-by: Zixuan Tan <tanzixuan.me@gmail.com>
This commit is contained in:
Zixuan Tan
2024-01-31 21:00:58 +08:00
parent 6e4d4c329a
commit 222de4f684
1 changed files with 18 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
src/agent/src/passfd_io.rs
View File

@@ -27,9 +27,11 @@ pub(crate) async fn start_listen(port: u32) -> Result<()> {
tokio::spawn(async move {
loop {
if let Ok((stream, Vsock(addr))) = listener.accept().await {
// We should insert the stream into the mapping as soon
// to minimize the risk of encountering race conditions.
let port = addr.port();
info!(sl(), "accept connection from peer port {}", port);
HVSOCK_STREAMS.lock().await.insert(port, stream);
info!(sl(), "accept connection from peer port {}", port);
}
}
});
@@ -37,8 +39,21 @@ pub(crate) async fn start_listen(port: u32) -> Result<()> {
}
async fn take_stream(port: u32) -> Option<VsockStream> {
let mut mapping = HVSOCK_STREAMS.lock().await;
mapping.remove(&port)
// There may be a race condition where the stream is accepted but
// not yet inserted into the mapping. We will retry several times.
// If it still fails, we just give up.
let mut count = 0;
while count < 3 {
let stream = HVSOCK_STREAMS.lock().await.remove(&port);
if stream.is_some() {
return stream;
}
tokio::time::sleep(tokio::time::Duration::from_millis(100)).await;
count += 1;
}
warn!(sl(), "failed to take stream for port {}", port);
None
}
macro_rules! take_io_stream {