Messages in this thread | | | From | Linus Torvalds <> | Date | Wed, 1 Dec 2010 17:05:43 -0800 | Subject | Re: [PATCH v2 3/3] NFS: Fix a memory leak in nfs_readdir |
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On Wed, Dec 1, 2010 at 3:36 PM, Andrew Morton <akpm@linux-foundation.org> wrote: > On Wed, 1 Dec 2010 15:31:11 -0800 > Linus Torvalds <torvalds@linux-foundation.org> wrote: >> >> Ergo: vmscan has a locked page leads to the filesystem being >> guaranteed to not be unmounted. And that, in turn, guarantees that >> the module won't be unloaded until the machine has gone through an >> idle cycle. > > The page isn't attached to the address_space any more:
Did you even read the email?
Here, let me quote the important parts:
"module won't be unloaded until the machine has gone through an idle cycle"
"This is pretty much how all the module races are handled. Doing module ref-counts per page (or per packet in flight for things like networking) would be prohibitively expensive."
IOW, the whole "stop_machine()" part is fundamental. That whole "module unload won't happen until we've gone through an idle cycle" is EXACTLY why we don't need to have the page attached or ref-counted - we're still safe.
Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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