mirror of
https://github.com/tailscale/tailscale.git
synced 2024-11-26 03:25:35 +00:00
0aa55bffce
In derpWriteChanOfAddr when we call derphttp.NewRegionClient(), there is a check of whether the connection is already errored and if so it returns before grabbing the lock. The lock might already be held and would be a deadlock. This corner case is not being reliably exercised by other tests. This shows up in code coverage reports, the lines of code in derpWriteChanOfAddr are alternately added and subtracted from code coverage. Add a test to specifically exercise this code path, and verify that it doesn't deadlock. This is the best tradeoff I could come up with: + the moment code calls Err() to check if there is an error, we grab the lock to make sure it would deadlock if it tries to grab the lock itself. + if a new call to Err() is added in this code path, only the first one will be covered and the rest will not be tested. + this test doesn't verify whether code is checking for Err() in the right place, which ideally I guess it would. Signed-off-by: Denton Gentry <dgentry@tailscale.com> |
||
|---|---|---|
| .. | ||
| discopingpurpose_string.go | ||
| legacy.go | ||
| magicsock_test.go | ||
| magicsock.go | ||