From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 02EC5C4708F for ; Wed, 2 Jun 2021 13:47:52 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7EFBB613B1 for ; Wed, 2 Jun 2021 13:47:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7EFBB613B1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:43192 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1loRDp-00037W-Q5 for qemu-devel@archiver.kernel.org; Wed, 02 Jun 2021 09:47:51 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43704) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1loRBz-0008Mo-Pd for qemu-devel@nongnu.org; Wed, 02 Jun 2021 09:45:55 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:39407) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1loRBw-00071L-4q for qemu-devel@nongnu.org; Wed, 02 Jun 2021 09:45:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1622641551; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MgFnAmrETwJamIS0R7FX5BEeNaWuQse4e92a2iXdJRE=; b=DhVavhEYqyyZ3v3ssloK/QbBpjWLD6mShHCikwKq/N/48Dt+wr1kUwFm2c6HJk0cRXluQJ TX+MH20C+GcOxju8qfV2ft88dm797ZLE/OiPTXnNopAhaJvhzN+I1NY6ZQ0MUrqJo295uX 4eptqO63LQ+fF8WWox88YJchCPqDZbo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-498-XNoPrqZaNeO5pYAVCC3Xnw-1; Wed, 02 Jun 2021 09:45:49 -0400 X-MC-Unique: XNoPrqZaNeO5pYAVCC3Xnw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E51011085929; Wed, 2 Jun 2021 13:45:39 +0000 (UTC) Received: from merkur.redhat.com (ovpn-114-240.ams2.redhat.com [10.36.114.240]) by smtp.corp.redhat.com (Postfix) with ESMTP id CE54419814; Wed, 2 Jun 2021 13:45:38 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PULL 04/20] block/vvfat: fix vvfat_child_perm crash Date: Wed, 2 Jun 2021 15:45:13 +0200 Message-Id: <20210602134529.231756-5-kwolf@redhat.com> In-Reply-To: <20210602134529.231756-1-kwolf@redhat.com> References: <20210602134529.231756-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.371, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Vladimir Sementsov-Ogievskiy It's wrong to rely on s->qcow in vvfat_child_perm, as on permission update during bdrv_open_child() call this field is not set yet. Still prior to aa5a04c7db27eea6b36de32f241b155f0d9ce34d, it didn't crash, as bdrv_open_child passed NULL as child to bdrv_child_perm(), and NULL was equal to NULL in assertion (still, it was bad guarantee for child being s->qcow, not backing :). Since aa5a04c7db27eea6b36de32f241b155f0d9ce34d "add bdrv_attach_child_noperm" bdrv_refresh_perms called on parent node when attaching child, and new correct child pointer is passed to .bdrv_child_perm. Still, s->qcow is NULL at the moment. Let's rely only on role instead. Without that fix, ./build/qemu-system-x86_64 -usb -device usb-storage,drive=fat16 \ -drive \ file=fat:rw:fat-type=16:"",id=fat16,format=raw,if=none crashes: (gdb) bt 0 raise () at /lib64/libc.so.6 1 abort () at /lib64/libc.so.6 2 _nl_load_domain.cold () at /lib64/libc.so.6 3 annobin_assert.c_end () at /lib64/libc.so.6 4 vvfat_child_perm (bs=0x559186f3d690, c=0x559186f1ed20, role=3, reopen_queue=0x0, perm=0, shared=31, nperm=0x7ffe56f28298, nshared=0x7ffe56f282a0) at ../block/vvfat.c:3214 5 bdrv_child_perm (bs=0x559186f3d690, child_bs=0x559186f60190, c=0x559186f1ed20, role=3, reopen_queue=0x0, parent_perm=0, parent_shared=31, nperm=0x7ffe56f28298, nshared=0x7ffe56f282a0) at ../block.c:2094 6 bdrv_node_refresh_perm (bs=0x559186f3d690, q=0x0, tran=0x559186f65850, errp=0x7ffe56f28530) at ../block.c:2336 7 bdrv_list_refresh_perms (list=0x559186db5b90 = {...}, q=0x0, tran=0x559186f65850, errp=0x7ffe56f28530) at ../block.c:2358 8 bdrv_refresh_perms (bs=0x559186f3d690, errp=0x7ffe56f28530) at ../block.c:2419 9 bdrv_attach_child (parent_bs=0x559186f3d690, child_bs=0x559186f60190, child_name=0x559184d83e3d "write-target", child_class=0x5591852f3b00 , child_role=3, errp=0x7ffe56f28530) at ../block.c:2959 10 bdrv_open_child (filename=0x559186f5cb80 "/var/tmp/vl.7WYmFU", options=0x559186f66c20, bdref_key=0x559184d83e3d "write-target", parent=0x559186f3d690, child_class=0x5591852f3b00 , child_role=3, allow_none=false, errp=0x7ffe56f28530) at ../block.c:3351 11 enable_write_target (bs=0x559186f3d690, errp=0x7ffe56f28530) at ../block/vvfat.c:3177 12 vvfat_open (bs=0x559186f3d690, options=0x559186f42db0, flags=155650, errp=0x7ffe56f28530) at ../block/vvfat.c:1236 13 bdrv_open_driver (bs=0x559186f3d690, drv=0x5591853d97e0 , node_name=0x0, options=0x559186f42db0, open_flags=155650, errp=0x7ffe56f28640) at ../block.c:1557 14 bdrv_open_common (bs=0x559186f3d690, file=0x0, options=0x559186f42db0, errp=0x7ffe56f28640) at ../block.c:1833 ... (gdb) fr 4 #4 vvfat_child_perm (bs=0x559186f3d690, c=0x559186f1ed20, role=3, reopen_queue=0x0, perm=0, shared=31, nperm=0x7ffe56f28298, nshared=0x7ffe56f282a0) at ../block/vvfat.c:3214 3214 assert(c == s->qcow || (role & BDRV_CHILD_COW)); (gdb) p role $1 = 3 # BDRV_CHILD_DATA | BDRV_CHILD_METADATA (gdb) p *c $2 = {bs = 0x559186f60190, name = 0x559186f669d0 "write-target", klass = 0x5591852f3b00 , role = 3, opaque = 0x559186f3d690, perm = 3, shared_perm = 4, frozen = false, parent_quiesce_counter = 0, next = {le_next = 0x0, le_prev = 0x559186f41818}, next_parent = {le_next = 0x0, le_prev = 0x559186f64320}} (gdb) p s->qcow $3 = (BdrvChild *) 0x0 Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210524101257.119377-3-vsementsov@virtuozzo.com> Tested-by: John Arbuckle Signed-off-by: Kevin Wolf --- block/vvfat.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/block/vvfat.c b/block/vvfat.c index 07232a7cfc..86d99c899c 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -3209,15 +3209,12 @@ static void vvfat_child_perm(BlockDriverState *bs, BdrvChild *c, uint64_t perm, uint64_t shared, uint64_t *nperm, uint64_t *nshared) { - BDRVVVFATState *s = bs->opaque; - - assert(c == s->qcow || (role & BDRV_CHILD_COW)); - - if (c == s->qcow) { + if (role & BDRV_CHILD_DATA) { /* This is a private node, nobody should try to attach to it */ *nperm = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE; *nshared = BLK_PERM_WRITE_UNCHANGED; } else { + assert(role & BDRV_CHILD_COW); /* The backing file is there so 'commit' can use it. vvfat doesn't * access it in any way. */ *nperm = 0; -- 2.30.2