[QPID-4168] Unhandled [rare] error condition in EpollPoller.cpp

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Auto Closed
• Affects Version/s: 0.16
• Component/s: C++ Client

Environment

RHEL 6.2 (probably all POSIX targets)

• Assignee: Andrew Stitcher
• Reporter: Rob Springer
• Created: 26/Jul/12 12:20
• Updated: 14/Mar/18 20:26
• Resolved: 14/Mar/18 20:26

Description

There was a bug in one of our programs wherein a thread could call close() on what was effectively a random socket.
Occasionally, it would happen to call close() on the alwaysReadableFd
registered in the PollerPrivate constructor, which would result in an epoll
event for that FD to be returned in the call to epoll_wait() on line 568. It'd
then try to dereference the event's "ptr" element (which was set to 0x1 on
registration for that FD), which would lead to a segfault.

It's worth reiterating that the triggering bug is absolutely not in Qpid, so this isn't a core functionality issue - it's more of a graceful handling of a unexpected error condition.