better SMP support for kprobes

[Frank Ch. Eigler]

Hi -


On Wed, Feb 02, 2005 at 03:31:19PM -0800, Martin Hunt wrote:
> Currently kprobe_handler grabs kprobe_lock and keeps it the entire time
> the probe is executing.  On SMP systems this could cause significant
> performance degradation [...]

More importantly, by reading the code, it seems like kprobes user
functions are called from within a context where interrupts are
blocked.  Would that not make it impossible to safely invoke
user-context might_sleep functions like copy_from_user, from any
of the kprobes, jprobes, dprobes layers?  I hope I'm missing
something!


- FChE
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