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Groups > linux.kernel > #1586342
| From | Kees Cook <keescook@chromium.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 1/4] fs, afs: convert afs_cell.usage from atomic_t to refcount_t |
| Date | 2017-02-22 18:40 +0100 |
| Message-ID | <tdJ3r-5dB-3@gated-at.bofh.it> (permalink) |
| References | <tdkRr-4uK-11@gated-at.bofh.it> <tdkRr-4uK-13@gated-at.bofh.it> <tdHO2-4nL-5@gated-at.bofh.it> <tdITL-57Y-9@gated-at.bofh.it> <tdJ3r-5dB-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Wed, Feb 22, 2017 at 9:29 AM, David Howells <dhowells@redhat.com> wrote: > Reshetova, Elena <elena.reshetova@intel.com> wrote: > >> 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. > > Or you could create a refcount_inc_may_resurrect() function that does allow > increment from 0. Make it take a lock-check like the rcu functions do. We can't allow the increment from 0 since it violates the intended use-after-free protections. If "0" means "still valid" then this sounds like it needs a global +1, as Elena suggested in her reply. -Kees -- Kees Cook Pixel Security
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[PATCH 1/4] fs, afs: convert afs_cell.usage from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-02-21 16:50 +0100
Re: [PATCH 1/4] fs, afs: convert afs_cell.usage from atomic_t to refcount_t David Howells <dhowells@redhat.com> - 2017-02-22 17:20 +0100
RE: [PATCH 1/4] fs, afs: convert afs_cell.usage from atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-02-22 18:30 +0100
Re: [PATCH 1/4] fs, afs: convert afs_cell.usage from atomic_t to refcount_t Kees Cook <keescook@chromium.org> - 2017-02-22 18:40 +0100
RE: [PATCH 1/4] fs, afs: convert afs_cell.usage from atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-02-23 14:40 +0100
Re: [PATCH 1/4] fs, afs: convert afs_cell.usage from atomic_t to refcount_t David Howells <dhowells@redhat.com> - 2017-02-24 15:30 +0100
Re: [PATCH 1/4] fs, afs: convert afs_cell.usage from atomic_t to refcount_t David Howells <dhowells@redhat.com> - 2017-02-22 18:40 +0100
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