From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 A201F2641C6 for ; Fri, 14 Feb 2025 13:16:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739539016; cv=none; b=l0oVa+9B7KUQ4T1xyds2pOl4Wn/VxO83ML4Yk72XbULu2256l7VohSgL3/g6KLqZQlkqPdyIV1UYq/tuDVT1IePDCtEJwI3F0EOjuhQG2L+t0EVKb05rUDAaMf4jDC8CHXpG6LNUdfmNjaYrumW7dRNF+JYZJ16Rg4MNTpufhvE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739539016; c=relaxed/simple; bh=4z1f4w3fc/rS+rR37tw4jvKtssLmhg7xJF+noxM8VNw=; h=From:In-Reply-To:References:To:Cc:Subject:MIME-Version: Content-Type:Date:Message-ID; b=OwXrVc6UX+J0uxeYeTlfZJgTpySEKPjwfbVaT5+DEXRKNungfKBHVJnbffqoaGZExlh85wDyPmwrPO6aWCqBpZOGSmEcnmtenKZ81F3gSImQbjvdAVsKWroTVKm0jU1HQt2mhFTAJok/47WRw3Cy7ldKvKgsntbxaPFfiAzjkbU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=YesuA9zq; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YesuA9zq" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1739539013; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=M24UA7C5snSotQt93BcJrFNpx6zFhQ3V7OApt+YZfGE=; b=YesuA9zqWIOrUpnT+fnvSIXfsKmyTdq2bg1YnncB5eo/CqMU95TPrKrCJOTlgNUbJ/c89S PRn+vmhJ5ntozIV00yhaMIxE3qvmGgz4nBdgzLVP/yHsF3WjJDzZFHcU81V8vutEOV3aqR Yt391rcYE64LGfNlmBLpnsSTZRLv7fc= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-685--G0UtyqJM92QBVRVbsr8hA-1; Fri, 14 Feb 2025 08:16:51 -0500 X-MC-Unique: -G0UtyqJM92QBVRVbsr8hA-1 X-Mimecast-MFC-AGG-ID: -G0UtyqJM92QBVRVbsr8hA_1739539011 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E6BE71800875; Fri, 14 Feb 2025 13:16:50 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.92]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 95DCF1941298; Fri, 14 Feb 2025 13:16:49 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20250214131225.492756-1-max.kellermann@ionos.com> References: <20250214131225.492756-1-max.kellermann@ionos.com> To: Max Kellermann Cc: dhowells@redhat.com, netfs@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v6.13 v2] fs/netfs/read_collect: fix crash due to uninitialized `prev` variable 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="us-ascii" Content-ID: <3979098.1739539008.1@warthog.procyon.org.uk> Date: Fri, 14 Feb 2025 13:16:48 +0000 Message-ID: <3979099.1739539008@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Max Kellermann wrote: > When checking whether the edges of adjacent subrequests touch, the > `prev` variable is deferenced, but it might not have been initialized. > This causes crashes like this one: > > BUG: unable to handle page fault for address: 0000000181343843 > ... > > Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading") > Cc: stable@vger.kernel.org > Signed-off-by: Max Kellermann Signed-off-by: David Howells