From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 DC23E230D1E for ; Fri, 14 Feb 2025 12:53:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739537628; cv=none; b=F1K29lfZsYS98/uuVT9PirEaB6TdnsC6QdZwMf3MjsZCEwN6KjDF6TZt2OFt2sSjPsk4U+ZtQlWDIzPUjHEGLITI9RS3+QhN2Dyg1Nubpoax4Qo/8oBQNha+mRnwpP2f6t2uDRjEtyrfVJ8EFX0zhs2oKvl8/Z+HtXRFulV7MqU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739537628; 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=KuRi2VWHDZnXn61IkiA3qr2yXKZuyEFHecHu0c1D0sQh3x+8oM5QN3pEb2jI6ErHHXYTNF0TQCxG74glZGK4W9DpRweHrBdqpY/CWtlNxWPrfG6etU0PkCxs1Q/iNrPFmDUnY91ty/9RCGha8uSze5Mn+MsEHk5k4E1vaLNGYNI= 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=APdeHuzq; arc=none smtp.client-ip=170.10.133.124 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="APdeHuzq" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1739537625; 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=APdeHuzqWiAPyeVwhM6SihAGjMPF2PL8UxAhIioyWOUiylcCAp0b3thMS8B7VlnKGeED0F 3kw2BBiaeFqFhPhV04uycJ2G1crQEfisDKYBlPz3au0E691O+W5yZyMZ+AWJMTJluEMNJE y74ihJZLVGUZNoqOWqieaMaqVEJfe8c= Received: from mx-prod-mc-06.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-460-rFv_Yn9pNEeo8NemprD6KA-1; Fri, 14 Feb 2025 07:53:42 -0500 X-MC-Unique: rFv_Yn9pNEeo8NemprD6KA-1 X-Mimecast-MFC-AGG-ID: rFv_Yn9pNEeo8NemprD6KA_1739537621 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AF2281800879; Fri, 14 Feb 2025 12:53:41 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.92]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 668DC300018D; Fri, 14 Feb 2025 12:53:40 +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: <20250211093432.3524035-1-max.kellermann@ionos.com> References: <20250211093432.3524035-1-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] fs/netfs/read_collect: fix crash due to uninitialized `prev` variable Precedence: bulk X-Mailing-List: netfs@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <3978181.1739537619.1@warthog.procyon.org.uk> Date: Fri, 14 Feb 2025 12:53:39 +0000 Message-ID: <3978182.1739537619@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 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