Thread switching and stepping bug

[Jonathan Larmour <jlarmour@redhat.com>]

It seems GDB (a fairly recent CVS) doesn't do the right thing when a thread
view has been switched and then the system stepped.

I've got a program with a bunch of threads. The default one is thread 3 and
has a function breakme which I set a breakpoint. The other threads run
other stuff.

If I set a breakpoint on breakme, thread 3 hits it. If I manually step off
that breakpoint, switch to e.g. thread 5 then do another step, GDB can't
recognise that it hit a sensible breakpoint, and instead reports a SIGTRAP.

So the commands I'm doing are:

b breakme
c
[ hits breakpoint in thread 3]
step
thread 5
step

I'm surprised no-one has noticed this before, so is my understanding wrong?

I've tried looking in wait_for_inferior() but got lost quickly :-). I think
the problem may be that step_resume_breakpoint is changed when GDB notices
the thread has changed. But I'm no expert.

Jifl
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