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Date: Mon, 11 Sep 2017 12:29:55 -0700 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: "Luis R. Rodriguez" <mcgrof@...nel.org> Cc: Marcel Holtmann <marcel@...tmann.org>, Linus Torvalds <torvalds@...ux-foundation.org>, Gabriel C <nix.or.die@...il.com>, Tejun Heo <tj@...nel.org>, "Gustavo F. Padovan" <gustavo@...ovan.org>, Sukumar Ghorai <sukumar.ghorai@...el.com>, "Rafael J. Wysocki" <rjw@...ysocki.net>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, "bluez mailin list (linux-bluetooth@...r.kernel.org)" <linux-bluetooth@...r.kernel.org> Subject: Re: btusb "firmware request while host is not available" at resume On Mon, Sep 11, 2017 at 07:11:38PM +0200, Luis R. Rodriguez wrote: > On Mon, Sep 11, 2017 at 06:46:47AM -0700, Greg Kroah-Hartman wrote: > > To confirm, reverting this fixes the problem I was seeing in 4.13. I've > > queued it up for the next 4.13-stable release as well. > > Commit 81f95076281f ("firmware: add sanity check on shutdown/suspend") may > seem kludgy but the reason for it was to cleanup the horrible forced and > required UMH lock even when the UMH lock was *not* even needed, which was later > removed via commit 06a45a93e7d34aa ("firmware: move umh try locks into the umh > code"). So what does this mean now that it is reverted? > Removing the old UMH lock even when the UMH lock was *not* needed was the right > thing to do but commit 81f95076281f (("firmware: add sanity check on > shutdown/suspend") was put in place as a safe guard as the lock was also > placing an implicit sanity check on the API. It ensures the API with the cache > was used as designed, otherwise you do run the risk of *not getting the > firmware you may need* -- Marcel seems to acknowledge this possibility. > > It may be possible for us to already have in place safeguards so that upon > resume we are ensuring the path to the firmware *is* available, so IMHO we > should remove this *iff* we can provide this guarantee. Otherwise the check is > valid. You see, although the UMH lock was bogus, it did implicitly ask the > question: is it safe for *any* helper to run and make assumptions on the > filesystem then? > > In lieu of this question being answered the warning is valid given the design > of the firmware API and the having the cache available as a measure to resolve > this race. I don't understand what you are trying to say here at all. To be specific, what, if anything, is a problem with the current state of Linus's tree (and the next 4.13-stable release)? If something needs to be fixed, can you make a patch showing that? Or do we also need to revert anything else as well to get back to a "better working" state? thanks, greg k-h
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