From: Andi Kleen <ak@muc.de>
To: prasanna@in.ibm.com
Cc: linux-kernel@vger.kernel.org
Subject: Re: [3/4] Jumper Probes patch to provide function arguments
Date: Wed, 11 Aug 2004 18:36:33 +0200 [thread overview]
Message-ID: <m3brhh4ooe.fsf@averell.firstfloor.org> (raw)
In-Reply-To: <2s3ZE-7Zq-29@gated-at.bofh.it> (Prasanna S. Panchamukhi's message of "Wed, 11 Aug 2004 18:20:10 +0200")
Prasanna S Panchamukhi <prasanna@in.ibm.com> writes:
+void jprobe_return(void)
+{
+ preempt_enable_no_resched();
+ asm volatile (" xchgl %%ebx,%%esp \n"
+ " int3 \n"::"b"
+ (jprobe_saved_esp):"memory");
+}
whatever the preempt disable is protecting against, why isn't it a
problem during the xchgl ?
> +#define MAX_STACK_SIZE 64
> +#define MIN_STACK_SIZE(ADDR) ((((ADDR) + MAX_STACK_SIZE) < \
> + (((ADDR) & PAGE_MASK) + PAGE_SIZE) ? ((ADDR) + MAX_STACK_SIZE) \
> + : (((ADDR) & PAGE_MASK) + PAGE_SIZE )) - (ADDR))
What is this macro doing exactly?
If it is an attempt to not read beyond the kernel stack top i think
it is wrong. It will also randomly fail on 8k stacks at top-4K
Use something like
max_t(unsigned long,MAX_STACK_SIZE, current_thread_info() + THREAD_SIZE - addr)
The rest looks ok.
-Andi
next parent reply other threads:[~2004-08-11 16:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <2s3ZE-7Zq-29@gated-at.bofh.it>
2004-08-11 16:36 ` Andi Kleen [this message]
2004-08-12 12:32 ` [3/4] Jumper Probes patch to provide function arguments Prasanna S Panchamukhi
2004-08-11 18:06 ` [3/4] Jumper Probes patch to provide function arguments II Andi Kleen
2004-08-11 16:15 [3/4] Jumper Probes patch to provide function arguments Prasanna S Panchamukhi
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