From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout01.posteo.de (mout01.posteo.de [185.67.36.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 394D03C3BEE for ; Sun, 6 Sep 2026 17:36:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.67.36.65 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788716217; cv=none; b=mZaDxW1P+kkuJpLHisf5OP8CmgvAoVCumZ2xkVPs2LnC04W/R+O8+0ZY/Dw7tW5iq/1g5AmorfGYc+nftWtF6zwEBr8YkwlcLr8HHK4/M4NmOoIN34TL94UNhPavepxDcXOxBd9FVi/+kp4oHhsZgRDUNnfCnc8j66mA/0ovg5I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788716217; c=relaxed/simple; bh=fYQ56hs4JZbOPzI9GDapvEN/e9D4SZhXgTO/mzH3DAU=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=W/AdnjI2f5LsaVRfRMCGojCGDUDFoWWa/OTikT3KHIbjhcl2+JUGLWRemgdFE8KYJJ+Je2h4ftGSHiwYx9AprdfiXDRN66AxD9bbrTGmmSDj1L93cZs8z9TL3obcwqOXp1q68e8jTezLEvars48TM63/bo8WtRxtZjAsaB96jhI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.de; spf=pass smtp.mailfrom=posteo.de; dkim=pass (2048-bit key) header.d=posteo.de header.i=@posteo.de header.b=BUESNfXR; arc=none smtp.client-ip=185.67.36.65 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=posteo.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=posteo.de header.i=@posteo.de header.b="BUESNfXR" Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id 1B278240029 for ; Sun, 6 Sep 2026 19:36:51 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=1984.8680eb; t=1788716211; bh=DOeFnrNegKPZyHyOuDBcouHZPqHJUHfv+oiAMmLgHoY=; h=Message-ID:Subject:From:To:Cc:Date:Autocrypt:Content-Type: MIME-Version:OpenPGP:From; b=BUESNfXR+UKLw1tFQelyLqKXqpf3Krmb1Hui7V+kwm4SrEL1hOahhW/7pY3mjql0Y kD9QnAyN7ihfAzGIj4bCKihGjpGLXpWl+CR9DqCUI7dBk2w4vMLTX+O7g+XGLcuduj c7busNO5Of5ZuVrXmuI6grrfnYiFfhfW7xZdqmrxPLAG9d5pOcCiq/DmstzbLQNnZN ZYYpoTqphUmBQNgThwpoQSTo0W/IpjMRbh8x8WMMTBzelTZHxf85T3o/5K0igBSBky uw6zbmKnciuMBjufgjSpl+1XO9/uQk5UqLav/NmAV5YUz0A5+KOGoE5wbTRdDm79R1 YmbO4zvEvBHTg== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4hdHSb1mS9z9rxN; Sun, 6 Sep 2026 19:36:47 +0200 (CEST) Message-ID: Subject: Re: [PATCH 5/5] rust: serdev: Pause receive callback before calling unbind From: Markus Probst To: Danilo Krummrich Cc: Ayush Singh , Johan Hovold , Alex Elder , Greg Kroah-Hartman , Miguel Ojeda , Boqun Feng , Gary Guo , =?ISO-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , Onur =?ISO-8859-1?Q?=D6zkan?= , Eric Biggers , Ard Biesheuvel , Lorenzo Stoakes , Vlastimil Babka , "Liam R. Howlett" , Uladzislau Rezki , Jiri Slaby , "Rafael J. Wysocki" , greybus-dev@lists.linaro.org, linux-serial@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, driver-core@lists.linux.dev Date: Sun, 06 Sep 2026 17:36:49 +0000 In-Reply-To: References: <20260906-rust_serdev_probe_refactor-v1-0-69cdae0074ec@posteo.de> <20260906-rust_serdev_probe_refactor-v1-5-69cdae0074ec@posteo.de> Autocrypt: addr=markus.probst@posteo.de; prefer-encrypt=mutual; keydata=mQINBGiDvXgBEADAXUceKafpl46S35UmDh2wRvvx+UfZbcTjeQOlSwKP7YVJ4JOZrVs93 qReNLkOWguIqPBxR9blQ4nyYrqSCV+MMw/3ifyXIm6Pw2YRUDg+WTEOjTixRCoWDgUj1nOsvJ9tVA m76Ww+/pAnepVRafMID0rqEfD9oGv1YrfpeFJhyE2zUw3SyyNLIKWD6QeLRhKQRbSnsXhGLFBXCqt 9k5JARhgQof9zvztcCVlT5KVvuyfC4H+HzeGmu9201BVyihJwKdcKPq+n/aY5FUVxNTgtI9f8wIbm fAjaoT1pjXSp+dszakA98fhONM98pOq723o/1ZGMZukyXFfsDGtA3BB79HoopHKujLGWAGskzClwT jRQxBqxh/U/lL1pc+0xPWikTNCmtziCOvv0KA0arDOMQlyFvImzX6oGVgE4ksKQYbMZ3Ikw6L1Rv1 J+FvN0aNwOKgL2ztBRYscUGcQvA0Zo1fGCAn/BLEJvQYShWKeKqjyncVGoXFsz2AcuFKe1pwETSsN 6OZncjy32e4ktgs07cWBfx0v62b8md36jau+B6RVnnodaA8++oXl3FRwiEW8XfXWIjy4umIv93tb8 8ekYsfOfWkTSewZYXGoqe4RtK80ulMHb/dh2FZQIFyRdN4HOmB4FYO5sEYFr9YjHLmDkrUgNodJCX CeMe4BO4iaxUQARAQABtCdNYXJrdXMgUHJvYnN0IDxtYXJrdXMucHJvYnN0QHBvc3Rlby5kZT6JAl QEEwEIAD4CGwMFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AWIQSCdBjE9KxY53IwxHM0dh/4561 D0gUCaIZ9HQIZAQAKCRA0dh/4561D0pKmD/92zsCfbD+SrvBpNWtbit7J9wFBNr9qSFFm2n/65qen NNWKDrCzDsjRbALMHSO8nigMWzjofbVjj8Nf7SDcdapRjrMCnidS0DuW3pZBo6W0sZqV/fLx+AzgQ 7PAr6jtBbUoKW/GCGHLLtb6Hv+zjL17KGVO0DdQeoHEXMa48mJh8rS7VlUzVtpbxsWbb1wRZJTD88 ALDOLTWGqMbCTFDKFfGcqBLdUT13vx706Q29wrDiogmQhLGYKc6fQzpHhCLNhHTl8ZVLuKVY3wTT+ f9TzW1BDzFTAe3ZXsKhrzF+ud7vr6ff9p1Zl+Nujz94EDYHi/5Yrtp//+N/ZjDGDmqZOEA86/Gybu 6XE/v4S85ls0cAe37WTqsMCJjVRMP52r7Y1AuOONJDe3sIsDge++XFhwfGPbZwBnwd4gEVcdrKhnO ntuP9TvBMFWeTvtLqlWJUt7n8f/ELCcGoO5acai1iZ59GC81GLl2izObOLNjyv3G6hia/w50Mw9MU dAdZQ2MxM6k+x4L5XeysdcR/2AydVLtu2LGFOrKyEe0M9XmlE6OvziWXvVVwomvTN3LaNUmaINhr7 pHTFwDiZCSWKnwnvD2+jA1trKq1xKUQY1uGW9XgSj98pKyixHWoeEpydr+alSTB43c3m0351/9rYT TTi4KSk73wtapPKtaoIR3rOFHLQXbWFya3VzLnByb2JzdEBwb3N0ZW8uZGWJAlEEEwEIADsWIQSCd BjE9KxY53IwxHM0dh/4561D0gUCaIO9eAIbAwULCQgHAgIiAgYVCgkICwIEFgIDAQIeBwIXgAAKCR A0dh/4561D0oHZEACEmk5Ng9+OXoVxJJ+c9slBI2lYxyBO84qkWjoJ/0GpwoHk1IpyL+i+kF1Bb7y Hx9Tiz8ENYX7xIPTZzS8hXs1ksuo76FQUyD6onA/69xZIrYZ0NSA5HUo62qzzMSZL7od5e12R6OPR lR0PIuc4ecOGCEq3BLRPfZSYrL54tiase8HubXsvb6EBQ8jPI8ZUlr96ZqFEwrQZF/3ihyV6LILLk geExgwlTzo5Wv3piOXPTITBuzuFhBJqEnT25q2j8OumGQ+ri8oVeAzx24g1kc11pwpR0sowfa5MvZ WrrBcaIL7uJfR/ig7FyGnTQ1nS3btf3p0v8A3fc4eUu/K2No3l2huJp3+LHhCmpmeykOhSB63Mj3s 3Q87LD0HE0HBkTEMwp+sD97ZRpO67H5shzJRanUaDTb/mREfzpJmRT1uuec0X2zItL7a6itgMJvYI KG29aJLX3fTzzVzFGPgzVZYEdhu4y53p0qEGrrC1JtKR6DRPE1hb/OdWOkjmJ75+PPLD9U5IuRd6y sHJWsEBR1F0wkMPkEofWsvMYJzWXx/rvTWO8N4D6HigTgBXAXNgbc3IHpHlkvKoBJptv6DRVRtIrz 0G0cfBY0Sm7he4N2IYDWWdGnPBZ3rlLSdj5EiBU2YWgIgtLrb8ZNJ3ZlhYluGnBJDGRqy2jC9s1jY 66sLA9rQZMHhJTzMyIDwweGlvMzJAcG9zdGVvLmV1PokCbQQTAQgAVxYhBIJ0GMT0rFjncjDEczR2 H/jnrUPSBQJpa71VGxSAAAAAAAQADm1hbnUyLDIuNSsxLjExLDIsMgIbAwULCQgHAgIiAgYVCgkIC wIEFgIDAQIeBwIXgAAKCRA0dh/4561D0gKJD/9uOQKYlsDoQX65Gd0LiMT0C+5vXgr3VI0PHDOwcv 51fJ3A1vNyPZRFPGrz8+mDEXUQOF/INfnz5Tu1QHwf+iYcWcTGAN/FHgVR6ET6VBNU2hJaKhu+Ggo kjYyJTOvyX+3yNRUfSny0GjTjIPuPTErjqmHF+BtjXslpgwqnNMznf3lRIuUjRORupos6p3k1DndE 5vzUTmXSvMyXyOD2KhBl/kL76k0bHYyAQytZPag12pltrtFbA/r2phDGN2si8PooDT99bSTJjaM45 MTAAHbHKJfvgfK41bNFD5mMtpWpL195XRtS0Nrxdg3PaYBxN5gtTG0RyZfpYRlkdEhm+jj/8RxuSG i/qdhRdbiI7K2IELWeQVHSNDi9JabR/UzlR4NSnhfAjRIVlRM+eFbUl8XwxwVrAkojF5IraH2qRvg VCmuFsHUW07FUlrDrzpjXsD73cKppoFGDCdDR0BHJepXbFLS9+AqkT+guRJlnCTg2p+TQtnbwPgKp Vj98JixovCl99zRYTsL2bRNU5+q8iET65VMJ1ydyNanvLd5vI/NqDkXhlXLsGmdaDTtu4R21PkToX dQNGrZ91M9nlIBKw8Y7c7xZ4098qX2b8JX/CxD+gC1r4C8vuA3GkhFLx+KlkON7LyiJPkrePp6Qky jfGillcaQOqFZ3WwVqyzG1BUfTow== Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-rnTpNxyRN/xwpGJ+AFb3" Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 OpenPGP: url=https://posteo.de/keys/markus.probst@posteo.de.asc; preference=encrypt --=-rnTpNxyRN/xwpGJ+AFb3 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Sun, 2026-09-06 at 18:20 +0200, Danilo Krummrich wrote: > On Sun Sep 6, 2026 at 5:55 PM CEST, Markus Probst wrote: > > @@ -200,10 +203,14 @@ extern "C" fn receive_buf_callback( > > // INVARIANT: `sdev` is valid for the duration of `receive_buf= _callback()`. > > let sdev =3D unsafe { &*sdev.cast::>() }; > > =20 > > - // SAFETY: `receive_buf_callback` is only ever called after a = successful call to > > - // `probe_callback`, hence it's guaranteed that `Device::set_d= rvdata()` has been called > > - // and stored a `Pin>>`. > > - let private_data =3D unsafe { sdev.as_ref().drvdata_borrow::>() }; > > + // SAFETY: > > + // - `receive_buf_callback` is only ever called after a succes= sful call to `probe_callback`, > > + // hence it's guaranteed that `Device::set_drvdata()` has be= en called and stored a > > + // `Pin>>`. > > + // - `unbind_callback` calls `serdev_device_pause_rx` before a= ccessing the driver data, > > + // which guarantees that this function will not overlap with= it. Thus we have exclusive > > + // access. > > + let private_data =3D unsafe { sdev.as_ref().drvdata_borrow_mut= ::>() }; >=20 > This would break the driver core's lifetime design. Any kind of registrat= ion > (such as class device, auxiliary, IRQ, etc.) may borrow fields from the b= us > device private data. The whole design is based on the guarantee that we n= ever > construct a mutable reference of the bus device private data. Thanks for the info. That explains why unbind doesn't provide a mutable reference on platform drivers either. I will drop the 2 patches in the next revision. Thanks - Markus Probst --=-rnTpNxyRN/xwpGJ+AFb3 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- iQJPBAABCAA5FiEEgnQYxPSsWOdyMMRzNHYf+OetQ9IFAmqdpKkbFIAAAAAABAAO bWFudTIsMi41KzEuMTIsMiwyAAoJEDR2H/jnrUPS0FMP+wetPILltgePj1usw34G G1LpNzCmHz5Zf9lWEu7r/zcmkY97jmpnWr8KzoZARisOm+eiJxkAi9FUkQe6s5B5 fnBQNDLyrLsqRj0a3z3pXhDzyKTXIaoMgSQ2m2f7yYpHS0yRfxWJGjdRd1PBNWyq gwy1XrPXJDoRWtG9unaBoF83qGdm9AfCJxGv3gRzVTdB7Dqu0EIKLyBkuRwYh6gK 6kmA5/ZCLSnLTFCP10fCb/FBRy2kcvNM7QZZlXpyilOUpIO1IOMyTWibPWumF/pg l31COrAHGxD2xZCM+z8b1ROwhgsz4UsVMHi8JYxS9/kHVDKq/L+rJn5oGte+X9CL F7kBU2UB9AcOFW/+GdHzw4UfRnd+18cqWTUvEISbkbhKLgzik5ie4RZN/KgQIIGy ousGkCFf0TT5N7HQf6R2/dvUernOBcMCBykpPo6udngT7ez7fmwA1lrm4Gh3BIQH nRaxJ4b47/Z4ymjYy32LstfJqJYFX2vLsHVZUzqWz4RV372FUipSIL+/cTsc9hRU n1sRWZnNrQ+psZVJTBj00b0R9dMSJEXa4s7fe9LMlFloUAeEN73yeC45U4J7b7LB wViW2m9sJrYFArAQw0tQLLCSPAkJq5fQi5aYMFSifh1xS3PFYMMMP+QNghkhLSZw 15QMwoNXu0oqGSmxCo0mvrj0 =iM0o -----END PGP SIGNATURE----- --=-rnTpNxyRN/xwpGJ+AFb3--