From patchwork Wed Dec 1 06:30:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Herbert Xu X-Patchwork-Id: 12649171 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B6527C433EF for ; Wed, 1 Dec 2021 06:30:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346933AbhLAGeO (ORCPT ); Wed, 1 Dec 2021 01:34:14 -0500 Received: from helcar.hmeau.com ([216.24.177.18]:57312 "EHLO fornost.hmeau.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231871AbhLAGeO (ORCPT ); Wed, 1 Dec 2021 01:34:14 -0500 Received: from gwarestrin.arnor.me.apana.org.au ([192.168.103.7]) by fornost.hmeau.com with smtp (Exim 4.92 #5 (Debian)) id 1msJ8b-0004tU-Bn; Wed, 01 Dec 2021 17:30:42 +1100 Received: by gwarestrin.arnor.me.apana.org.au (sSMTP sendmail emulation); Wed, 01 Dec 2021 17:30:41 +1100 Date: Wed, 1 Dec 2021 17:30:41 +1100 From: Herbert Xu To: Heiner Kallweit Cc: Shixin Liu , "Rafael J. Wysocki" , Linux PM , Linux Crypto Mailing List Subject: crypto: stm32 - Revert broken pm_runtime_resume_and_get changes Message-ID: <20211201063041.GC684@gondor.apana.org.au> References: <4239b61f-f8c5-462f-2951-fbba2dec8b1d@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <4239b61f-f8c5-462f-2951-fbba2dec8b1d@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Sat, Nov 27, 2021 at 02:39:52PM +0100, Heiner Kallweit wrote: > When discussing whether pm_runtime_resume_and_get() should be annotated as > __must_check, I became aware of RPM usage in crypto/stm32. > > Following two patches replace usage of pm_runtime_get_sync() with > pm_runtime_resume_and_get() w/o checking the return code. > > 747bf30fd944 ("crypto: stm32/cryp - Fix PM reference leak on stm32-cryp.c") > 1cb3ad701970 ("crypto: stm32/hash - Fix PM reference leak on stm32-hash.c") > > This results in RPM usage like the following in stm32_hash_export(): > > pm_runtime_resume_and_get(hdev->dev); > ... > pm_runtime_mark_last_busy(hdev->dev); > pm_runtime_put_autosuspend(hdev->dev); > > This is broken. After pm_runtime_resume_and_get() the usage count may be > incremented or not. If not, then the call to pm_runtime_put_autosuspend() > results in exactly the imbalance that the patch claims to fix. > > Therefore I think both patches should be reverted, or the return code > of pm_runtime_resume_and_get() has to be checked and properly handled > in the driver logic. I agree. But we can't revert them completely because it does fix some genuine issues with the ones where we do check the error code. What about this patch? ---8<--- We should not call pm_runtime_resume_and_get where the reference count is expected to be incremented unconditionally. This patch reverts these calls to the original unconditional get_sync call. Reported-by: Heiner Kallweit Fixes: 747bf30fd944 ("crypto: stm32/cryp - Fix PM reference leak...") Fixes: 1cb3ad701970 ("crypto: stm32/hash - Fix PM reference leak...") Signed-off-by: Herbert Xu Acked-by: Rafael J. Wysocki diff --git a/drivers/crypto/stm32/stm32-cryp.c b/drivers/crypto/stm32/stm32-cryp.c index 7389a0536ff0..05087831e199 100644 --- a/drivers/crypto/stm32/stm32-cryp.c +++ b/drivers/crypto/stm32/stm32-cryp.c @@ -542,7 +542,7 @@ static int stm32_cryp_hw_init(struct stm32_cryp *cryp) int ret; u32 cfg, hw_mode; - pm_runtime_resume_and_get(cryp->dev); + pm_runtime_get_sync(cryp->dev); /* Disable interrupt */ stm32_cryp_write(cryp, CRYP_IMSCR, 0); diff --git a/drivers/crypto/stm32/stm32-hash.c b/drivers/crypto/stm32/stm32-hash.c index 389de9e3302d..d33006d43f76 100644 --- a/drivers/crypto/stm32/stm32-hash.c +++ b/drivers/crypto/stm32/stm32-hash.c @@ -813,7 +813,7 @@ static void stm32_hash_finish_req(struct ahash_request *req, int err) static int stm32_hash_hw_init(struct stm32_hash_dev *hdev, struct stm32_hash_request_ctx *rctx) { - pm_runtime_resume_and_get(hdev->dev); + pm_runtime_get_sync(hdev->dev); if (!(HASH_FLAGS_INIT & hdev->flags)) { stm32_hash_write(hdev, HASH_CR, HASH_CR_INIT); @@ -962,7 +962,7 @@ static int stm32_hash_export(struct ahash_request *req, void *out) u32 *preg; unsigned int i; - pm_runtime_resume_and_get(hdev->dev); + pm_runtime_get_sync(hdev->dev); while ((stm32_hash_read(hdev, HASH_SR) & HASH_SR_BUSY)) cpu_relax(); @@ -1000,7 +1000,7 @@ static int stm32_hash_import(struct ahash_request *req, const void *in) preg = rctx->hw_context; - pm_runtime_resume_and_get(hdev->dev); + pm_runtime_get_sync(hdev->dev); stm32_hash_write(hdev, HASH_IMR, *preg++); stm32_hash_write(hdev, HASH_STR, *preg++);