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 3717C37A836 for ; Sat, 5 Sep 2026 13:30:23 +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=1788615032; cv=none; b=JSdWRV+v8/zSkkR7zPN+AfMk2Wz5TsP9CFPJWKR8JwLKXBUW1WJQ3SC1LvJC8m38bBBZ1rEw9axQeOVKSbpqFSF3p9GaMfkRE/DqISti0eOcw1SVyFsQtk8XbGBJTj+h7AoyE3tP4cqJe2ELz1DBwa529ILzpEGPTlOxxnNXjbk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788615032; c=relaxed/simple; bh=0sSBP2cprqjuaV+c2HHo+xNsGybFsYHAYG6+y+2l4nU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=q5r03Xn+0pgSt3oVy6t2iErSzq/JzmG80Fb1iu84WC6/cugp0rBcfxbY8N73lilx7a044m9KqpWxA2iGOfgTk5fwueIG433GH3Ft3ruR+TaqovUmGiA/EufA5bpm4DhhbD6DkW/PcpTvypIOEckc0A53JuCo3oITfUqhp2oCdCA= 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=eS0WYOXm; 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="eS0WYOXm" Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id 3300124002A for ; Sat, 5 Sep 2026 15:30:13 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=1984.8680eb; t=1788615013; bh=bfa+sUbkpDzQYYGeZZKcZXo0idL7gh16q6bK32R5j28=; h=From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:To:Cc:Autocrypt:OpenPGP:From; b=eS0WYOXmli7nWeEa6tSmNdMlEuJkVq+NIDUd6Iui1oJZiLCiZH1uCrV6koQOX1tMJ 6qRzErvKtw38L37TuQWFTfHE7g1NoMhpI7Fbm+0uwl3ks5IQ16GhrgTSnEPu26S26Y v/HwRAAbPaWf3gUMpL1HUgwPc0GRFdFloV0SfvwHquWl9bnR88ZjYlBZYGJsb2nfxz YoLggbACG+2QtGdryeCucA+sbXE59EaV89OipHkaA+EZeFy+j6yKo1xrxWmQmu57WO epsErNND8y18PzL2XUjnZQQruPLJeOHIxhKFr9hmMZYICxmBx5xurGs6AtBhSuk+7c Ul+e451TuxWqQ== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4hcZ2W0Bztz9rxL; Sat, 5 Sep 2026 15:30:11 +0200 (CEST) From: Markus Probst Date: Sat, 05 Sep 2026 13:30:12 +0000 Subject: [PATCH v2 2/2] rust: serdev: Fix race condition on driver probe Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260905-rust_serdev_fix-v2-2-35dfcd06ef2e@posteo.de> References: <20260905-rust_serdev_fix-v2-0-35dfcd06ef2e@posteo.de> In-Reply-To: <20260905-rust_serdev_fix-v2-0-35dfcd06ef2e@posteo.de> To: Miguel Ojeda , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , =?utf-8?q?Onur_=C3=96zkan?= , Greg Kroah-Hartman , "Rafael J. Wysocki" Cc: linux-serial@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, driver-core@lists.linux.dev, Markus Probst , Sashiko Bot X-Developer-Signature: v=1; a=openpgp-sha256; l=3431; i=markus.probst@posteo.de; h=from:subject:message-id; bh=0sSBP2cprqjuaV+c2HHo+xNsGybFsYHAYG6+y+2l4nU=; b=owEBiQJ2/ZANAwAIATR2H/jnrUPSAcsmYgBqnBlfx2sPL/zq72ZUWElTRxokkNvkBYNGBmbWf o3+JzcuPymJAk8EAAEIADkWIQSCdBjE9KxY53IwxHM0dh/4561D0gUCapwZXxsUgAAAAAAEAA5t YW51MiwyLjUrMS4xMiwyLDIACgkQNHYf+OetQ9IdLhAAhyNMuqVjsUADZqyxpUP9bzZSUF5WmyE rnAWo28VtYYoWXJ+DEdD1fZgUdVHvYiWduM8TcQUXC9RMy9CvX5oNZI5U0tjFPmWGEGDKDGGY+S EFc8y5ObBQHti0z6aM4fK/5mdCs3hl8ZXi/GNGyYc9oe2AmMtCDzCU42NK2I3Lqs+EppgpbRB8I QXPEYw0f2ZzjRxXZ3u9yOWdyWMzZJKKjiNnIgDag/lE98iGcgr5Av4dFm5qGalRKpkVoxhBLhqt BBushxqbesNgH+fvkOywUwZty8yfqoHjZmm4qfEGi9YIxYkwOntDGC0MfT6C1oECrRRLdfUT8kj Vk2pK5/Y4JazAc4Q85HFFyhNRWfjf/HIbnXldOYnASP2/fH3gipbA6b3Djeb9ks3xFA5x8GFqW4 ifNm4Q8Jowirf4uHuKfpN5K4JMp1gCQpUeKQeBPVd/++MJtKs8BpQ00nCAO4IzqjxP3VX2huxy4 TzmqM9IN0ocfDZyzr6MeTxbKxOTr79BMaDoZCR/ge+zst7HofawHa8W67yLMqVufLz7tG72R31a 2CrIzB5waBPeE9VytsgsiHhcsZLeLJuTGJyFvsz1OSBLtS17SvCWCVGLJIojIn927bRdzL05VwS 9u/Avb1uSeCsFIb8vL+lC9TFWIZQWm7gx78/WN1ZuwraVL4lJWeU= X-Developer-Key: i=markus.probst@posteo.de; a=openpgp; fpr=827418C4F4AC58E77230C47334761FF8E7AD43D2 Autocrypt: addr=markus.probst@posteo.de; prefer-encrypt=mutual; keydata=xsFNBGiDvXgBEADAXUceKafpl46S35UmDh2wRvvx+UfZbcTjeQOlSwKP7YVJ4JOZrVs93qReNLkO WguIqPBxR9blQ4nyYrqSCV+MMw/3ifyXIm6Pw2YRUDg+WTEOjTixRCoWDgUj1nOsvJ9tVAm76Ww+ /pAnepVRafMID0rqEfD9oGv1YrfpeFJhyE2zUw3SyyNLIKWD6QeLRhKQRbSnsXhGLFBXCqt9k5JA RhgQof9zvztcCVlT5KVvuyfC4H+HzeGmu9201BVyihJwKdcKPq+n/aY5FUVxNTgtI9f8wIbmfAja oT1pjXSp+dszakA98fhONM98pOq723o/1ZGMZukyXFfsDGtA3BB79HoopHKujLGWAGskzClwTjRQ xBqxh/U/lL1pc+0xPWikTNCmtziCOvv0KA0arDOMQlyFvImzX6oGVgE4ksKQYbMZ3Ikw6L1Rv1J+ FvN0aNwOKgL2ztBRYscUGcQvA0Zo1fGCAn/BLEJvQYShWKeKqjyncVGoXFsz2AcuFKe1pwETSsN6 OZncjy32e4ktgs07cWBfx0v62b8md36jau+B6RVnnodaA8++oXl3FRwiEW8XfXWIjy4umIv93tb8 8ekYsfOfWkTSewZYXGoqe4RtK80ulMHb/dh2FZQIFyRdN4HOmB4FYO5sEYFr9YjHLmDkrUgNodJC XCeMe4BO4iaxUQARAQABzRdtYXJrdXMucHJvYnN0QHBvc3Rlby5kZcLBkQQTAQgAOxYhBIJ0GMT0 rFjncjDEczR2H/jnrUPSBQJog714AhsDBQsJCAcCAiICBhUKCQgLAgQWAgMBAh4HAheAAAoJEDR2 H/jnrUPSgdkQAISaTk2D345ehXEkn5z2yUEjaVjHIE7ziqRaOgn/QanCgeTUinIv6L6QXUFvvIfH 1OLPwQ1hfvEg9NnNLyFezWSy6jvoVBTIPqicD/r3FkithnQ1IDkdSjrarPMxJkvuh3l7XZHo49GV HQ8i5zh5w4YISrcEtE99lJisvni2Jqx7we5tey9voQFDyM8jxlSWv3pmoUTCtBkX/eKHJXosgsuS B4TGDCVPOjla/emI5c9MhMG7O4WEEmoSdPbmraPw66YZD6uLyhV4DPHbiDWRzXWnClHSyjB9rky9 lausFxogvu4l9H+KDsXIadNDWdLdu1/enS/wDd9zh5S78rY2jeXaG4mnf4seEKamZ7KQ6FIHrcyP ezdDzssPQcTQcGRMQzCn6wP3tlGk7rsfmyHMlFqdRoNNv+ZER/OkmZFPW655zRfbMi0vtrqK2Awm 9ggobb1oktfd9PPNXMUY+DNVlgR2G7jLnenSoQausLUm0pHoNE8TWFv851Y6SOYnvn488sP1Tki5 F3rKwclawQFHUXTCQw+QSh9ay8xgnNZfH+u9NY7w3gPoeKBOAFcBc2BtzcgekeWS8qgEmm2/oNFV G0ivPQbRx8FjRKbuF7g3YhgNZZ0ac8FneuUtJ2PkSIFTZhaAiC0utvxk0ndmWFiW4acEkMZGrLaM L2zWNjrqwsD2zsFNBGiDvXgBEADCXQy1n7wjRxG12DOVADawjghKcG+5LtEf31WftHKLFbp/HArj BhkT6mj+CCI1ClqY+FYU5CK/s0ScMfLxRGLZ0Ktzawb78vOgBVFT3yB1yWBTewsAXdqNqRooaUNo 8cG/NNJLjhccH/7PO/FWX5qftOVUJ/AIsAhKQJ18Tc8Ik73v427EDxuKb9mTAnYQFA3Ev3hAiVbO 6Rv39amVOfJ8sqwiSUGidj2Fctg2aB5JbeMln0KCUbTD1LhEFepeKypfofAXQbGwaCjAhmkWy/q3 IT1mUrPxOngbxdRoOx1tGUC0HCMUW1sFaJgQPMmDcR0JGPOpgsKnitsSnN7ShcCr1buel7vLnUMD +TAZ5opdoF6HjAvAnBQaijtK6minkrM0seNXnCg0KkV8xhMNa6zCs1rq4GgjNLJue2EmuyHooHA4 7JMoLVHcxVeuNTp6K2+XRx0Pk4e2Lj8IVy9yEYyrywEOC5XRW37KJjsiOAsumi1rkvM7QREWgUDe Xs0+RpxI3QrrANh71fLMRo7LKRF3Gvw13NVCCC9ea20P4PwhgWKStkwO2NO+YJsAoS1QycMi/vKu 0EHhknYXamaSV50oZzHKmX56vEeJHTcngrM8R1SwJCYopCx9gkz90bTVYlitJa5hloWTYeMD7FNj Y6jfVSzgM/K4gMgUNDW/PPGeMwARAQABwsF2BBgBCAAgFiEEgnQYxPSsWOdyMMRzNHYf+OetQ9IF AmiDvXgCGwwACgkQNHYf+OetQ9LHDBAAhk+ab8+WrbS/b1/gYW3q1KDiXU719nCtfkUVXKidW5Ec Idlr5HGt8ilLoxSWT2Zi368iHCXS0WenGgPwlv8ifvB7TOZiiTDZROZkXjEBmU4nYjJ7GymawpWv oQwjMsPuq6ysbzWtOZ7eILx7cI0FjQeJ/Q2baRJub0uAZNwBOxCkAS6lpk5Fntd2u8CWmDQo4SYp xeuQ+pwkp0yEP30RhN2BO2DXiBEGSZSYh+ioGbCHQPIV3iVj0h6lcCPOqopZqyeCfigeacBI0nvN jHWz/spzF3+4OS+3RJvoHtAQmProxyGib8iVsTxgZO3UUi4TSODeEt0i0kHSPY4sCciOyXfAyYoD DFqhRjOEwBBxhr+scU4C1T2AflozvDwq3VSONjrKJUkhd8+WsdXxMdPFgBQuiKKwUy11mz6KQfcR wmDehF3UaUoxa+YIhWPbKmycxuX/D8SvnqavzAeAL1OcRbEI/HsoroVlEFbBRNBZLJUlnTPs8ZcU 4+8rq5YX1GUrJL3jf6SAfSgO7UdkEET3PdcKFYtS+ruV1Cp5V0q4kCfI5jk25iiz8grM2wOzVSsc l1mEkhiEPH87HP0whhb544iioSnumd3HJKL7dzhRegsMizatupp8D65A2JziW0WKopa1iw9fti3A aBeNN4ijKZchBXHPgVx+YtWRHfcm4l8= OpenPGP: url=https://posteo.de/keys/markus.probst@posteo.de.asc; preference=encrypt If `Driver::probe` fails, the pointer to the driver data (`PrivateData`) will first be set to NULL by `drvdata_obtain` and only after that the serdev device will be closed by Drop. Thus there is a small window in which the serdev device is still open, but the pointer to the driver data is NULL. Therefore it is possible that `receive_buf_callback` might try to access the `active` mutex on a null pointer. Use previously added `drvdata_drop` instead of `drvdata_obtain`, so the serdev device will first be closed with Drop and after that the pointer to the driver data will be set to NULL. Remove `drvdata_obtain`, as it is now dead code. Fixes: 99f59aa82341 ("rust: add basic serial device bus abstractions") Reported-by: Sashiko Bot Closes: https://lore.kernel.org/linux-serial/20260903222159.70A911F000E9@smtp.kernel.org/ Signed-off-by: Markus Probst --- rust/kernel/device.rs | 25 ------------------------- rust/kernel/serdev.rs | 2 +- 2 files changed, 1 insertion(+), 26 deletions(-) diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs index 3886cc713c28..834fea0eb0a7 100644 --- a/rust/kernel/device.rs +++ b/rust/kernel/device.rs @@ -213,31 +213,6 @@ pub fn set_drvdata(&self, data: impl PinInit) -> Result { Ok(()) } - /// Take ownership of the private data stored in this [`Device`]. - /// - /// # Safety - /// - /// - The type `T` must match the type of the `ForeignOwnable` previously stored by - /// [`Device::set_drvdata`]. - /// - Must only be called before the device is fully unbound. - pub(crate) unsafe fn drvdata_obtain(&self) -> Option>> { - // SAFETY: By the type invariants, `self.as_raw()` is a valid pointer to a `struct device`. - let ptr = unsafe { bindings::dev_get_drvdata(self.as_raw()) }; - - // SAFETY: By the type invariants, `self.as_raw()` is a valid pointer to a `struct device`. - unsafe { bindings::dev_set_drvdata(self.as_raw(), core::ptr::null_mut()) }; - - if ptr.is_null() { - return None; - } - - // SAFETY: - // - If `ptr` is not NULL, it comes from a previous call to `into_foreign()`. - // - `dev_get_drvdata()` guarantees to return the same pointer given to `dev_set_drvdata()` - // in `into_foreign()`. - Some(unsafe { Pin::>::from_foreign(ptr.cast()) }) - } - /// Drop the private data stored in this [`Device`]. /// /// The pointer to the private data remains valid until the drop is complete. diff --git a/rust/kernel/serdev.rs b/rust/kernel/serdev.rs index 17ca504b7f8d..a12b1dea12aa 100644 --- a/rust/kernel/serdev.rs +++ b/rust/kernel/serdev.rs @@ -176,7 +176,7 @@ extern "C" fn probe_callback(sdev: *mut bindings::serdev_device) -> kernel::ffi: let private_data = unsafe { sdev.as_ref().drvdata_borrow::>() }; let private_data = ScopeGuard::new_with_data(private_data, |_| { // SAFETY: We just set drvdata to `PrivateData<'_, T>`. - drop(unsafe { sdev.as_ref().drvdata_obtain::>() }); + unsafe { sdev.as_ref().drvdata_drop::>() }; }); let mut active = private_data.active.lock(); -- 2.55.0