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From: daniel-kay3@arcor.de
To: systemtap@sourceware.org
Subject: Dereferencing simple pointers
Date: Tue, 24 Nov 2009 17:42:00 -0000	[thread overview]
Message-ID: <26472256.1259084550376.JavaMail.ngmail@webmail08.arcor-online.net> (raw)

Hello Folks,
I am playing around with systemtap and am quite impressed. But there is one thing that confuses me. Is there any way that I can derefernce a single pointer from a function parameter inside a probe?

Example:

# Function from current Kernel (drivers/char/random.c:1049):
urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
{
       return extract_entropy_user(&nonblocking_pool, buf, nbytes);
}

# My Probe Attempt without success:
probe kernel.function("urandom_read") {
        printf("%s\n", *($ppos));
}

I can't believe that this isn't possible...

Thanks in advance,
Daniel Kay

             reply	other threads:[~2009-11-24 17:42 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-24 17:42 daniel-kay3 [this message]
2009-11-24 19:47 ` Frank Ch. Eigler
2009-11-24 19:59   ` Josh Stone
  -- strict thread matches above, loose matches on Subject: below --
2009-11-24 17:27 daniel-kay

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