From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793829756; b=5kPlGDP/QLzckQ4/gazNsu6XLGNlo/xPnA0cBvW+Zus5f1Xp5KWQmJ+XL9Jx3fVqdM5o 16Shp5kyUaoP3XD4PXGGwRD1fVr7oSql8QoTrEhElWxiseJhTfrDPnB3m2dGh7rojRq2M Gf+E2zfH4mmj+kUM8cR3wNLnT/HXnTH2zklYumoIZo3Ri5rg+PMBmHK2My0vNY4JYFjYm YlNp4YmU/0GIe0wChJ6LXwFISxFtOja3NaAlHefNSeanI9l5ZYtwvUvM75/cSxVRm0PZD 2kLy52fMRrgCWTH6Loj6bA7RRYdj5Tq8aj3kfZNeS+XiCggWW3tOyvq/ipqKXiBuRNg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793829756; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=IVo0KET7T5bE8MorwBDi0hMsJk2nCfCFdovpdKofcXk=; b=J4tzZUKnCf9/T52DX/eZLv8fI+NiR4Y71D1yaqhgs18huxztZSSjnHOBks8xX54vLG6k 2VTqBBJnjk669i3FfI1TvY+fAU3CxDaE2lXoUuZf7FVA0b0zbxMSiuhHHTF/SvLMHBzvg 8xrWKMIlQyMYJjhaEJ3ErI6ufkPZL5Cc0M3epstDf+1csedc1l8krLS5BHseh1dg26WvI INVqNlJQ0Bdcsu9jbZ/wBfHBDkha5lcazkRGA0K/9s1sQCPjWlCDsU8mXYj2r8nQ6mUkl TEVh1qAjGBH/h46PCCMQDpi9mX/IjclPVxQegsuJW48Jc2lEk+DEPRQ5IF6Ipzfm8MA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=udyvo2Gj; 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 1453A606C5AD; Wed, 4 Nov 2026 22:02:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=udyvo2Gj Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9FD881F000C1; Wed, 4 Nov 2026 22:02:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793829755; bh=IVo0KET7T5bE8MorwBDi0hMsJk2nCfCFdovpdKofcXk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=udyvo2GjnwpL2yKU/q6J6Vt2zHmeu6g/coN3zNmxq729SvAjJJGvcsJMByWIg+RB0 DDAeHFFsBwA74gnpVeLgTbbXPXxy1lU0Obj4MN0hktmHsAxSSrqc9AwJfN8LIQCilR Wd+6zztkvwW/PajbFm8DqHrf62oCUG468eeVydng= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Jan=20H=C3=B6ppner?= , Stefan Haberland , Jens Axboe , Sasha Levin Subject: [PATCH 6.18 0323/1005] s390/dasd: Snapshot intrc before freeing the request block Date: Wed, 4 Nov 2026 16:00:56 -0500 Message-ID: <20261104211052.992804393@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stefan Haberland [ Upstream commit dc3e3f7306cb74066f231251602b1be5aaec7bd8 ] __dasd_cleanup_cqr() maps the completion result to a block status by reading cqr->intrc, but only after discipline->free_cp() has returned the request block to its memory pool (dasd_eckd_free_cp() ends in dasd_sfree_request()). On SMP another CPU can reallocate that block and overwrite cqr->intrc before it is read, completing the request with the wrong error. proc_bytes is already snapshotted before free_cp() for the same reason; do the same for intrc. Reviewed-by: Jan Höppner Signed-off-by: Stefan Haberland Link: https://patch.msgid.link/20260805111612.1285190-5-sth@linux.ibm.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/s390/block/dasd.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c index e7845c8ccc9ff..f6e86692a21d7 100644 --- a/drivers/s390/block/dasd.c +++ b/drivers/s390/block/dasd.c @@ -2736,17 +2736,23 @@ static void __dasd_cleanup_cqr(struct dasd_ccw_req *cqr) struct request *req; blk_status_t error = BLK_STS_OK; unsigned int proc_bytes; - int status; + int status, intrc; req = (struct request *) cqr->callback_data; dasd_profile_end(cqr->block, cqr, req); + /* + * free_cp() returns the request block to its memory pool, so snapshot + * everything still needed from cqr before calling it - another CPU can + * reallocate and overwrite the block right after. + */ proc_bytes = cqr->proc_bytes; + intrc = cqr->intrc; status = cqr->block->base->discipline->free_cp(cqr, req); if (status < 0) error = errno_to_blk_status(status); else if (status == 0) { - switch (cqr->intrc) { + switch (intrc) { case -EPERM: /* * DASD doesn't implement SCSI/NVMe reservations, but it -- 2.53.0