Different behaviour running under strace?

[Tom Horsley]

Here's a weird one: A system at work has (God knows why) a
gazillion symlinks directly under / pointing to NFS mountpoints
for filesystems (some of which might well have high latency).

If I run "df -l", using the -l option in the apparently
vain hope that it might not timeout forever on some NFS
mount, it hangs for a long time.

If I try to discover which mountpoint it hangs at by running
"strace df -l", it no longer hangs. All the stat calls run
fast, and df prints the info on the local filesystems.

There isn't supposed to be any difference running under
strace (except maybe for setuid and such), any clues what
weird rabbit hole this is going down?

I'm tempted to alias df to strace -o /dev/null df :-).