Messages in this thread | | | Date | Sun, 9 Nov 2014 21:19:08 +0000 | From | Al Viro <> | Subject | Re: [PATCH 1/4] inet: Add skb_copy_datagram_iter |
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[Michael Cc'd]
On Fri, Nov 07, 2014 at 11:42:53PM +0000, Al Viro wrote:
> I'll finish RTFS drivers/vhost and if it turns out to be OK I'll post the > series moving those checks to the moment of copying iovec from userland, > so that kernel-side we could always rely on ->msg_iov elements having been > verified.
Two questions: 1) does sparc64 access_ok() need to differ for 32bit and 64bit tasks? AFAICS, x86 and ppc just check that address is OK for 64bit process - if a 32bit process passes the kernel an address that would be valid for 64bit process, but not for 32bit one, we just get a pagefault in __copy_from_user() and friends. No kernel objects are going to have a virtual address in that range, so access_ok() doesn't bother preventing such access attempts there...
2) shouldn't vhost_dev_cleanup() stop the worker thread before doing anything else? AFAICS, we do parts of vhost_dev teardown while the thread is still running; granted, we keep dev->mm pinned down until after it stops (or we would be _really_ screwed), but is it safe to do all those fput()s, etc. while it's still running? Michael?
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