Re: Fix asm constraint in put_user

From: David Mosberger-Tang <David.Mosberger_at_acm.org>
Date: 2005-11-22 09:38:18
On 11/21/05, Andreas Schwab <schwab@suse.de> wrote:

> There is nothing worth clobbering here.  The memory written to is
> completely separate to anything GCC knows about.  The old version didn't
> clobber either.

That's usually true, but I don't think it's always true.  Consider the
case where put_user() is used to write kernel memory (which happens in
the ia32 emulation layer, for example).  I agree it's probably
extremely unlikely for this to trigger a real problem (especially
considering that the kernel is compiled without strict aliasing) but
still, the safe thing to do would be to add a "memory" clobber if
there is no better alternative.

  --david
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Received on Tue Nov 22 09:39:43 2005

This archive was generated by hypermail 2.1.8 : 2005-11-22 09:39:50 EST