From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Begunkov Subject: Re: IORING_REGISTER_CREDS[_UPDATE]() and credfd_create()? Date: Wed, 29 Jan 2020 17:34:21 +0300 Message-ID: <1f7cafc5-1969-1c6d-6fb1-441854d60fcb@gmail.com> References: <688e187a-75dd-89d9-921c-67de228605ce@samba.org> <1ac31828-e915-6180-cdb4-36685442ea75@kernel.dk> <0d4f43d8-a0c4-920b-5b8f-127c1c5a3fad@kernel.dk> <2d7e7fa2-e725-8beb-90b9-6476d48bdb33@gmail.com> <6c401e23-de7c-1fc1-4122-33d53fcf9700@kernel.dk> <35eebae7-76dd-52ee-58b2-4f9e85caee40@kernel.dk> <6e5ab6bf-6ff1-14df-1988-a80a7c6c9294@gmail.com> <2019e952-df2a-6b57-3571-73c525c5ba1a@kernel.dk> <0df4904f-780b-5d5f-8700-41df47a1b470@kernel.dk> <5406612e-299d-9d6e-96fc-c962eb93887f@gmail.com> <821243e7-b470-ad7a-c1a5-535bee58e76d@samba.org> <9a419bc5-4445-318d-87aa-1474b49266dd@gmail.com> <40d52623-5f9c-d804-cdeb-b7da6b13cb4f@samba.org> <3e1289de-8d8e-49cf-cc9f-fb7bc67f35d5@gmail.com> <6ebe1e2f-77f4-ae88-e184-c140a911cbd8@samba.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <6ebe1e2f-77f4-ae88-e184-c140a911cbd8-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org> Content-Language: en-US Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Stefan Metzmacher , Jens Axboe Cc: io-uring , Linux API Mailing List List-Id: linux-api@vger.kernel.org On 1/29/2020 5:27 PM, Stefan Metzmacher wrote: >> Great, that you turned attention to that! override_creds() is already >> grabbing a ref, so it shouldn't call get_cred() there. >> So, that's a bug. >> >> It could be I'm wrong with the statement above, need to recheck all this >> code to be sure. >> >> BTW, io_req_defer_prep() may be called twice for a req, so you will >> reassign it without putting a ref. It's safer to leave NULL checks. At >> least, until I've done reworking and fixing preparation paths. > > Ok, but that would be already a bug in > "io_uring/io-wq: don't use static creds/mm assignments" > instead of logically being part of > "io_uring: support using a registered personality for commands" Right. Probably should be backported there, since it's just 2 commits before. -- Pavel Begunkov