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From: Russell Currey <ruscur@russell.cc>
To: Christophe Leroy <christophe.leroy@c-s.fr>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [RFC PATCH] powerpc/mm: Implement STRICT_MODULE_RWX
Date: Tue, 21 May 2019 14:33:17 +1000	[thread overview]
Message-ID: <6a90db30c8543d547ab8543fbdba02f7fe6a4898.camel@russell.cc> (raw)
In-Reply-To: <df502ffe07caa38c46b0144fc824fff447f4105b.1557901092.git.christophe.leroy@c-s.fr>

On Wed, 2019-05-15 at 06:20 +0000, Christophe Leroy wrote:

Confirming this works on hash and radix book3s64.

> +
> +	// only operate on VM areas for now
> +	area = find_vm_area((void *)addr);
> +	if (!area || end > (unsigned long)area->addr + area->size ||
> +	    !(area->flags & VM_ALLOC))
> +		return -EINVAL;

https://lore.kernel.org/patchwork/project/lkml/list/?series=391470

With this patch, the above series causes crashes on (at least) Hash,
since it adds another user of change_page_rw() and change_page_nx()
that for reasons I don't understand yet, we can't handle.  I can work
around this with:

	if (area->flags & VM_FLUSH_RESET_PERMS)
		return 0;

so this is broken on at least one platform as of 5.2-rc1.  We're going
to look into this more to see if there's anything else we have to do as
a result of this series before the next merge window, or if just
working around it like this is good enough.

- Russell


      parent reply	other threads:[~2019-05-21  4:33 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-15  6:20 [RFC PATCH] powerpc/mm: Implement STRICT_MODULE_RWX Christophe Leroy
2019-05-15  6:42 ` Christoph Hellwig
2019-05-15  6:44   ` Christophe Leroy
2019-05-16  0:51 ` Russell Currey
2019-05-21  4:33 ` Russell Currey [this message]

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