lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 14 Mar 2022 18:47:11 -0700 From: Linus Torvalds <torvalds@...ux-foundation.org> To: Marcelo Roberto Jimenez <marcelo.jimenez@...il.com> Cc: Guenter Roeck <linux@...ck-us.net>, Thierry Reding <treding@...dia.com>, Linus Walleij <linus.walleij@...aro.org>, Vidya Sagar <vidyas@...dia.com>, Edmond Chung <edmondchung@...gle.com>, Andrew Chant <achant@...gle.com>, Will McVicker <willmcvicker@...gle.com>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Bartosz Golaszewski <brgl@...ev.pl> Subject: Re: Linux 5.17-rc8 On Mon, Mar 14, 2022 at 5:45 PM Marcelo Roberto Jimenez <marcelo.jimenez@...il.com> wrote: > > At a certain point, I tried Thorsten's suggestion to add a gpio-ranges > property in a way similar to another patch, but the kernel went into > an EPROBE_DEFER deadlock. Thierry Reding made some comments about this > in the sequence. Hmm. The problem does sound like that particular driver doesn't use the pin_ranges thing, so then the tests for an empty pin_ranges will always be true. The EPROBE_DEFER deadlock then sounds like something went wrong in the gpio-ranges patch when you tried to fix it - but I don't actually find that patch or that attempt, so I can't even guess at it. This whole code pin_ranges code looks very odd: gpiochip_add_pin{group}_range() seems to add the pin ranges properly, but that actual gpiochip_add_pin_ranges() function does *not*. It just expects that that the 'add_pin_ranges()' callback exists, and if it doesn't, does nothing at all. Which then makes those if (list_empty(&gc->gpiodev->pin_ranges)) return 0; tests very suspicious - because if some doesn't implement that add_pin_ranges() callback, it looks like nothing at all ever gets done, because nothing calls the function to actually add the pinrange. And then that "list_empty()" test very much will trigger. IOW, it looks like either a gpio controller has to implement that 'add_pin_ranges()' function (only tegra), or it needs to always add the pin ranges at probe time. Am I guessing right that the driver that you use does neither? LinusW/Bartoz - this all really sounds strange to me. Maybe I'm misreading the situation entirely. Should there be some sanity-test that any gpio/pinctrl driver that uses gpiochip_generic_request() would either have to have that add_pin_ranges() callback, or a successful probe needs to always populate that 'gpiodev->pin_ranges' list? Or maybe I'm misreading the situation entirely. I don't know the code - I'm just grepping for things and trying to make sense of how that '->pin_ranges' list is supposed to work. But for now, I think that patch has to be reverted. Linus
Powered by blists - more mailing lists