Messages in this thread | | | From | Denis Efremov <> | Subject | Re: [Cocci] [PATCH 1/2] Coccinelle: extend memdup_user transformation with GFP_USER | Date | Sat, 6 Jun 2020 23:36:21 +0300 |
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On 6/6/20 11:24 AM, Julia Lawall wrote: > > > On Sat, 30 May 2020, Denis Efremov wrote: > >> Match GFP_USER allocations with memdup_user.cocci rule. >> Commit 6c2c97a24f09 ("memdup_user(): switch to GFP_USER") switched >> memdup_user() from GFP_KERNEL to GFP_USER. In most cases it is still >> a good idea to use memdup_user() for GFP_KERNEL allocations. The >> motivation behind altering memdup_user() to GFP_USER is here: >> https://lkml.org/lkml/2018/1/6/333 > > Should the rule somehow document the cases in which memdup_user should now > not be used?
As for now, I can't provide a counterexample. GPF_USER is more permissive than GFP_KERNEL. It's completely ok to use GPF_USER with copy_from_user. Given that memdup_user() was "silently" switched to GPF_USER from GPF_KERNEL with no callside fixes, I think it's ok to recommend to use memdup_user for GPF_KERNEL matches with no additional restrictions.
Thanks, Denis
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