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smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=J+teH0MB; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A0709606A31C for ; Fri, 30 Oct 2026 14:13:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=J+teH0MB Received: by smtp.kernel.org (Postfix) with ESMTPSA id 464361F000C1; Fri, 30 Oct 2026 14:13:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793369637; bh=8tQsj2DZrJpwTGDEw+GbhQJEYsSO/PoAIUNE/LKFKe0=; h=Date:Subject:From:To:Cc:References:In-Reply-To; b=J+teH0MBGP4Ozg/6Nd/fclZtqK3zkm7KQLC7da0Tyw1h2FoVlYSaHTKLgk7mj9QZG AGnjp/S6/uCsFnJ+xNQLmg8CxeUynUMia+DVxQ7brD+uStsEhpu5dcad7uQJfkFB/l vWxsgMIDwnVf9/fhc898MpmM2tCFfwlupesw0nvYUHoPw2w4msIn8zIkRma5ayczhN 93v2TKeRkJnCs07JATd53NaEg+LDrhJtIrboekPhaHfalcgHuVoM33nYXk4FSgdLbJ kwIF+q+udBWjyn87tGqu92vRUyWlJvsJVBlz0gF1Kk9pQ6kkbNpOxhoTa4BoAueoKy /dvL1DHdyWrTA== Message-ID: Date: Fri, 30 Oct 2026 15:13:53 +0100 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] memory: fsl_ifc: Clear global controller pointer on probe failure and remove From: Krzysztof Kozlowski To: Reid Downing Cc: linux-kernel@vger.kernel.org References: <20261025170833.1316443-1-skibletz@gmail.com> <987c08da-646d-4d34-82f4-da8c3afaed59@kernel.org> Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 30/10/2026 15:10, Krzysztof Kozlowski wrote: > On 25/10/2026 18:08, Reid Downing wrote: >> fsl_ifc_ctrl_dev is assigned early in fsl_ifc_ctrl_probe() to a >> devm-allocated structure. If probe fails afterwards, or when the device >> is removed, that memory is freed and the registers are unmapped, but the >> global still points at it. fsl_ifc_find() and fsl_ifc_nand_probe() only >> check it for NULL, so a later call can dereference freed memory or an >> unmapped register region. >> >> Clear the pointer on the probe error paths and in remove, once the IRQs >> have been released. The global cannot be published later in probe >> instead, because ifc_in32()/ifc_out32() and the NAND child probed from >> of_platform_default_populate() depend on it. >> >> Signed-off-by: Reid Downing >> --- >> Changes in v3: >> - Use my real name in Author and Signed-off-by (earlier versions had a >> handle appended). >> - Generate the patch with git against drivers/memory/fsl_ifc.c; the >> earlier versions used a path that could not be applied. Sorry for the >> noise, and for sending two unversioned copies. Those were v1 and v2, >> and this v3 supersedes them. >> - Change of approach: v1 and v2 delayed publishing fsl_ifc_ctrl_dev until >> the end of probe, but ifc_in32()/ifc_out32() and fsl_ifc_nand_probe() >> use the global during probe, so that would break the driver. v3 keeps >> the early assignment and instead clears the pointer on probe failure >> and in remove. >> - Dropped the nand_irq guard from the earlier versions; it was unrelated >> to this fix. >> >> Not compile-tested (no PowerPC build setup); the change is four >> assignments of NULL. > > Independently I want through Sashiko reports and tried to fix this with > LLM... and then remembered about your patch. Unfortunately I am not > taking unbuilt code, especially that build testing it is trivial. > > >> >> drivers/memory/fsl_ifc.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/memory/fsl_ifc.c b/drivers/memory/fsl_ifc.c >> index e89e0c6cc..abacd90d6 100644 >> --- a/drivers/memory/fsl_ifc.c >> +++ b/drivers/memory/fsl_ifc.c >> @@ -95,6 +95,8 @@ static void fsl_ifc_ctrl_remove(struct platform_device *dev) >> irq_dispose_mapping(ctrl->nand_irq); >> irq_dispose_mapping(ctrl->irq); >> >> + /* Children and IRQs are gone; stop lookups before unmapping. */ >> + fsl_ifc_ctrl_dev = NULL; >> iounmap(ctrl->gregs); >> >> dev_set_drvdata(&dev->dev, NULL); >> @@ -218,6 +220,7 @@ static int fsl_ifc_ctrl_probe(struct platform_device *dev) >> fsl_ifc_ctrl_dev->gregs = of_iomap(dev->dev.of_node, 0); >> if (!fsl_ifc_ctrl_dev->gregs) { >> dev_err(&dev->dev, "failed to get memory region\n"); >> + fsl_ifc_ctrl_dev = NULL; > > This is supposed to be goto error path. > >> return -ENODEV; >> } >> >> @@ -300,6 +303,7 @@ static int fsl_ifc_ctrl_probe(struct platform_device *dev) >> irq_dispose_mapping(fsl_ifc_ctrl_dev->irq); >> err: >> iounmap(fsl_ifc_ctrl_dev->gregs); >> + fsl_ifc_ctrl_dev = NULL; >> return ret; > > Please let me know if you intend to send v4 which is going to be at > least built or I take what LLM produced me. > If v4, then please credit also Sashiko: Reported-by: Sashiko Closes: https://sashiko.dev/#/bug/linux-47538f77-fb50-4a06-b49b-92dbee8b538b Best regards, Krzysztof