Messages in this thread | | | From | "Reshetova, Elena" <> | Subject | RE: [PATCH] fs, cifs: convert tcon_link.tl_count from atomic_t to refcount_t | Date | Tue, 31 Oct 2017 09:41:46 +0000 |
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> Elena Reshetova <elena.reshetova@intel.com> writes: > > atomic_t variables are currently used to implement reference > > counters with the following properties: > > - counter is initialized to 1 using atomic_set() > > - a resource is freed upon counter reaching zero > > - once counter reaches zero, its further > > increments aren't allowed > > - counter schema uses basic atomic operations > > (set, inc, inc_not_zero, dec_and_test, etc.) > > > > Such atomic variables should be converted to a newly provided > > refcount_t type and API that prevents accidental counter overflows > > and underflows. This is important since overflows and underflows > > can lead to use-after-free situation and be exploitable. > > > > The variable tcon_link.tl_count is used as pure reference counter. > > Convert it to refcount_t and fix up the operations. > > <snip> > > > - cifs_get_tlink(tlink); > > + refcount_set(&tlink->tl_count, 1); > > Since cifs_get_tlink() basically only increments the reference count and > given that this is a new tlink I also think this replacement is ok. > > Looks good to me and passes 'make C=1'. > > Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Thank you very much for your review Aurelien! Do you know who would be the person to take this patch further?
Best Regards, Elena.
> > -- > Aurélien Aptel / SUSE Labs Samba Team > GPG: 1839 CB5F 9F5B FB9B AA97 8C99 03C8 A49B 521B D5D3 > SUSE Linux GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany > GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
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