The Resolver Issue

[pkmoore]

There is a weird issue around a replay delta with resolve.conf

Currently this is being worked around by disabling the name resolution machinery and entering host information in the hosts file. Current hypothesis is that there is some sort of caching or external mechanism causing problems.

Since the vDSO fix was put in place this delta presents itself as a call to gettimeofday() rather than a call to close() during the name resolution recvfrom() + poll() loop (in wget).

[pkmoore]

To enable workaround:
modify nsswitch.conf:
hosts: files (remove "dns")

modify host.conf:
order hosts (remove ", bind")

Configure network manager to "manually configure" network interface (or it will talk to resolvconf and work around your changes)

Undo these changes to undo the work-around. Don't forget to change network interface back to DHCP in network manager

[pkmoore]

The failure occurs in the call to res_send made by getaddrinfo. Simple test case is the callgetaddr sample program.

I need a way to debug deeper into the libc function.

Because of new checks, the failure now presents as a difference between the number of bytes requested by the recvfrom() calls made in a loop by this function.

[pkmoore]

Memory contents in first 512 bytes of stack frame before getaddrinfo() call are different in strace'd execution, replayed execution, and normal execution