Messages in this thread | | | Date | Mon, 02 Mar 2015 12:39:11 +0100 | From | Alexander Holler <> | Subject | Re: gadgetfs broken since 7f7f25e8 |
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Am 02.03.2015 um 11:20 schrieb Al Viro: > On Mon, Mar 02, 2015 at 10:13:27AM +0100, Richard Weinberger wrote: >> On Mon, Mar 2, 2015 at 9:28 AM, Alexander Holler <holler@ahsoftware.de> wrote: >>> Hello. >>> >>> Commit 7f7f25e82d54870df24d415a7007fbd327da027b (introduced with 3.16) broke >>> dynamic changing of file_operations->[read|write]. >>> >>> At least gadgetfs is a victim. >>> >>> Feel free to ask me off-list for a patch as I don't want to end up in >>> annoying discussions on Linux kernel lists anymore. >>> >>> Alexander Holler >> >> CC'ing Al. > > I know. FWIW, gadgetfs is one of the very few places that tried to pull that > crap off and it had always been seriously racy. I've posted a partial analysis > about a month ago (<20150204190645.GJ29656@ZenIV.linux.org.uk>). > > If Alexander (or anybody else) has a patch that really fixes that thing, > I would certainly like to see it. If not, I'll try to cook something, > but I'm not very familiar with that code. I really hope that this patch > isn't "modify ->f_mode to match ->f_op change" - that's too racy. > We'll obviously need to fix the userland-visible breakage in that one, > but that's not the way to go...
I exactly did what you've assumed, I've just fixed f_mode but not the already existing races which I haven't introduced. So I was right in not sending a patch as would have been blamed for not rewriting everything as so often.
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