Messages in this thread | | | Date | Tue, 16 Jun 2020 12:08:07 +0300 | From | Dan Carpenter <> | Subject | Re: [PATCH v4 1/3] mm/slab: Use memzero_explicit() in kzfree() |
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On Tue, Jun 16, 2020 at 08:42:08AM +0200, Michal Hocko wrote: > On Mon 15-06-20 21:57:16, Waiman Long wrote: > > The kzfree() function is normally used to clear some sensitive > > information, like encryption keys, in the buffer before freeing it back > > to the pool. Memset() is currently used for the buffer clearing. However, > > it is entirely possible that the compiler may choose to optimize away the > > memory clearing especially if LTO is being used. To make sure that this > > optimization will not happen, memzero_explicit(), which is introduced > > in v3.18, is now used in kzfree() to do the clearing. > > > > Fixes: 3ef0e5ba4673 ("slab: introduce kzfree()") > > Cc: stable@vger.kernel.org > > Signed-off-by: Waiman Long <longman@redhat.com> > > Acked-by: Michal Hocko <mhocko@suse.com> > > Although I am not really sure this is a stable material. Is there any > known instance where the memset was optimized out from kzfree?
I told him to add the stable. Otherwise it will just get reported to me again. It's a just safer to backport it before we forget.
regards, dan carpenter
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