Messages in this thread | | | From | "Reshetova, Elena" <> | Subject | RE: [PATCH 1/4] fs, afs: convert afs_cell.usage from atomic_t to refcount_t | Date | Wed, 22 Feb 2017 17:19:49 +0000 |
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> Elena Reshetova <elena.reshetova@intel.com> wrote: > > > refcount_t type and corresponding API should be > > used instead of atomic_t when the variable is used as > > a reference counter. This allows to avoid accidental > > refcounter overflows that might lead to use-after-free > > situations. > > This causes an assertion failure because cells aren't immediately destroyed > when their refcount reaches 0, but may be resurrected provided the cache lock > is held. However, attempting to increment the 0 refcount does nothing, not > even giving a warning.
This is strange, it is supposed to give a warning I think now when it is even not inlined. Peter, am I confusing smth?
> > So please place a hold on this patch. I will check the other AFS patches also. >
Thank you very much David for testing the patches! I guess for this one and other two patches it means that if we want to do the atomic_t --> refcount_t conversions, we need to do +1 on the whole counting scheme to avoid issues around reaching zero. Do you see this approach reasonable? I can give it a try, if it makes sense in your opinion.
Best Regards, Elena.
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