Re: trace_printk is doing weird things with my arguments

From: Steven Rostedt
Date: Mon Dec 12 2011 - 15:45:06 EST


On Mon, 2011-12-12 at 15:32 -0500, Josef Bacik wrote:
>
> That worked perfectly. So will I have this problem when I got to turn these
> things into tracepoints or will those work out right? Thanks,

The TP_fast_assign() is exactly how things are copied into the ring
buffer. If you have all the necessary data copied then, and don't
dereference it in TP_printk(), then you are fine.

IOW,

TP_fast_assign( entry->id = ptr->id),
TP_printk ("id: %lx", entry->id)

will work, but

TP_fast_assign(entry->ptr = ptr),
TP_printk("id: %lx", entry->ptr->id)

will not.


-- Steve


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