Messages in this thread | | | Date | Wed, 20 Mar 2019 12:26:07 +0200 | From | Jarkko Sakkinen <> | Subject | Re: scif_insert_vma() |
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On Sun, Mar 17, 2019 at 10:47:40PM -0700, Sudeep Dutt wrote: > On Mon, 2019-03-11 at 08:45 +0200, Jarkko Sakkinen wrote: > > Hi > > > > Just wondering what will happen if kzalloc() fails in scif_mmap.c. How > > it is recovered? I don't see anything in the VMA callbacks taking care > > of this. > > Hi Jarkko, > > scif_insert_vma(..) is called from scif_mmap(..) and scif_vma_open(..). > scif_mmap(..) checks for allocation failures but scif_vma_open(..) does > not on purpose. > > The vm_operations_struct open(..)/close(..) callbacks do not allow > returning errors. The driver will take a reference to the VMA private > data structure irrespective of whether the allocation during the > open(..) callback succeeds or fails. The close(..) callback cleans up > the data structures from the mmap(..) or open(..) callbacks if any.
I'm doing allocations also in SGX vma_open callback and was grepping through kernel tree for how allocations were handled. Thanks for clarifying this. In SGX's case I ended up with allowing to fail in vma open and doing SIGBUS in the #PF handler if so...
/Jarkko
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