ptrace single-stepping change breaks Wine

Eric Pouech pouech-eric at
Fri Nov 19 14:41:44 CST 2004

> Btw, does wine ever _use_ PTRACE_SINGLESTEP for any of the things it does?
> If it does, then that woulc certainly explain why my "fix" made no 
> difference: my fix _only_ handles the case where the ptracer never 
> actually asks for single-stepping, and single-stepping was started 
> entirely by the program being run (ie by setting TF in eflags from within 
> the program itself).
> But if wine ends up using PTRACE_SINGESTEP because wine actually wants to 
> single-step over some instructions, then the kernel will set the PT_DTRACE 
> bit, and start tracing through signal handlers too. The way Wine doesn't 
> want..

wine mixes both approches, we have (to control what's generated inside the 
various exception) to ptrace from our NT-kernel-like process (the ptracer) to 
get the context of the exception. Restart from the ptracer is done with 

(BTW: I also CC:ed wine-devel ML, that might be of interest to them too)


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