Ah-ha! - The first thread is in the poller, dispatching a command, invoking a callback handler with mutex `0x1e4600a0`. - The second thread is a callback handler, holding mutex `0x1e4600a0`, that is sending a command to the poller and waiting for a response. Classic order-of-lock issue. Poller is waiting on the mutex held by callback; callback is holding on the mutex waiting on the poller. -- Reply to this email directly or view it on GitHub: https://github.com/xrootd/xrootd/issues/1979#issuecomment-1485042900 You are receiving this because you commented. Message ID: <[log in to unmask]> ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the XROOTD-DEV list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=XROOTD-DEV&A=1