[lldb-dev] lldb hangs during reverse-connect if lldb-server dies
gclayton at apple.com
Wed Jun 17 13:28:17 PDT 2015
We should implement a timeout of say 5 seconds (since this is a locally spawned lldb-server) and also watch for the spawned lldb-server process to be reaped. If the lldb-server gets reaped we need to cancel. Don't do any fancy thread canceling (no pthread_cancel or anything like that) if you do fix this, just have something locally connect to the socket and allow the accept thread to exit normally.
> On Jun 17, 2015, at 11:32 AM, Ted Woodward <ted.woodward at codeaurora.org> wrote:
> With reverse-connect, lldb gets a port from the OS, spawns a listen thread using the port, and launches lldb-server/debugserver, telling it to connect back to lldb. lldb with then join with the listen thread. The listen thread calls accept() to wait for the server to connect back to it.
> On Linux (and possibly other OSes), if lldb-server dies or quits before connecting, lldb will hang. It sits waiting for accept() to return, but it never will.
> If the child dies, the listen thread should be killed, and an error returned to the user.
> This is easily seen on Linux. Simply point to an alternate debugserver. Set LLDB_DEBUGSERVER_PATH to something else, say /bin/ls. This will finish and never connect back to lldb.
> -> setenv LLDB_DEBUGSERVER_PATH /bin/ls
> ->bin/lldb /bin/ls
> (lldb) target create "/bin/ls"
> Current executable set to '/bin/ls' (x86_64).
> (lldb) r
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