lkml.org 
[lkml]   [2019]   [Jul]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] mm: check for sleepable context in kvfree
On Tue, Jul 23, 2019 at 01:52:36PM -0400, Jeff Layton wrote:
> On Tue, 2019-07-23 at 09:12 -0400, Jeff Layton wrote:
> > A lot of callers of kvfree only go down the vfree path under very rare
> > circumstances, and so may never end up hitting the might_sleep_if in it.
> > Ensure that when kvfree is called, that it is operating in a context
> > where it is allowed to sleep.
> >
> > Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> > Cc: Luis Henriques <lhenriques@suse.com>
> > Signed-off-by: Jeff Layton <jlayton@kernel.org>
> > ---
> > mm/util.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
>
> FWIW, I started looking at this after Luis sent me some ceph patches
> that fixed a few of these problems. I have not done extensive testing
> with this patch, so maybe consider this an RFC for now.
>
> HCH points out that xfs uses kvfree as a generic "free this no matter
> what it is" sort of wrapper and expects the callers to work out whether
> they might be freeing a vmalloc'ed address. If that sort of usage turns
> out to be prevalent, then we may need another approach to clean this up.

I think it's a bit of a landmine, to be honest. How about we have kvfree()
call vfree_atomic() instead?

\
 
 \ /
  Last update: 2019-07-23 19:57    [W:0.144 / U:0.332 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site