From nobody Mon Apr 29 17:31:47 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 15114561977991000.4673589172661; Thu, 23 Nov 2017 08:56:37 -0800 (PST) Received: from localhost ([::1]:45189 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eHune-0000G2-NN for importer@patchew.org; Thu, 23 Nov 2017 11:56:30 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40573) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eHumo-0008NF-2J for qemu-devel@nongnu.org; Thu, 23 Nov 2017 11:55:39 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eHumm-00064F-O8 for qemu-devel@nongnu.org; Thu, 23 Nov 2017 11:55:38 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:31284) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eHumh-0005yE-WF; Thu, 23 Nov 2017 11:55:32 -0500 Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id vANGtSiW010502 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 23 Nov 2017 16:55:28 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id vANGtSxs012619 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 23 Nov 2017 16:55:28 GMT Received: from abhmp0007.oracle.com (abhmp0007.oracle.com [141.146.116.13]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id vANGtSbn003830; Thu, 23 Nov 2017 16:55:28 GMT Received: from deepas-x1.oracle.com (/10.197.177.219) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 23 Nov 2017 08:55:27 -0800 From: Deepa Srinivasan To: stefanha@redhat.com, kwolf@redhat.com, mreitz@redhat.com, pbonzini@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org, mark.kanda@oracle.com Date: Thu, 23 Nov 2017 08:55:07 -0800 Message-Id: <1511456107-7081-1-git-send-email-deepa.srinivasan@oracle.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: X-Source-IP: userv0022.oracle.com [156.151.31.74] X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4.x-2.6.x [generic] [fuzzy] X-Received-From: 156.151.31.81 Subject: [Qemu-devel] [PATCH] block: Fix qemu crash when using scsi-block X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Deepa Srinivasan , Konrad Rzeszutek Wilk Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Starting qemu with the following arguments causes qemu to segfault: ... -device lsi,id=3Dlsi0 -drive file=3Discsi:<...>,format=3Draw,if=3Dnone,= node-name=3D iscsi1 -device scsi-block,bus=3Dlsi0.0,id=3D<...>,drive=3Discsi1 This patch fixes blk_aio_ioctl() so it does not pass stack addresses to blk_aio_ioctl_entry() which may be invoked after blk_aio_ioctl() returns. M= ore details about the bug follow. blk_aio_ioctl() invokes blk_aio_prwv() with blk_aio_ioctl_entry as the coroutine parameter. blk_aio_prwv() ultimately calls aio_co_enter(). When blk_aio_ioctl() is executed from within a coroutine context (e.g. iscsi_bh_cb()), aio_co_enter() adds the coroutine (blk_aio_ioctl_entry) to the current coroutine's wakeup queue. blk_aio_ioctl() then returns. When blk_aio_ioctl_entry() executes later, it accesses an invalid pointer: .... BlkRwCo *rwco =3D &acb->rwco; rwco->ret =3D blk_co_ioctl(rwco->blk, rwco->offset, rwco->qiov->iov[0].iov_base); <--- qiov is invalid he= re ... In the case when blk_aio_ioctl() is called from a non-coroutine context, blk_aio_ioctl_entry() executes immediately. But if bdrv_co_ioctl() calls qemu_coroutine_yield(), blk_aio_ioctl() will return. When the coroutine execution is complete, control returns to blk_aio_ioctl_entry() after the c= all to blk_co_ioctl(). There is no invalid reference after this point, but the function is still holding on to invalid pointers. The fix is to change blk_aio_prwv() to accept a void pointer for the IO buf= fer rather than a QEMUIOVector. blk_aio_prwv() passes this through in BlkRwCo a= nd the coroutine function casts it to QEMUIOVector or uses the void pointer direct= ly. Signed-off-by: Deepa Srinivasan Signed-off-by: Konrad Rzeszutek Wilk Reviewed-by: Mark Kanda --- block/block-backend.c | 51 +++++++++++++++++++++++++----------------------= ---- 1 file changed, 25 insertions(+), 26 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index baef8e7..2d0d9b6 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -1140,7 +1140,7 @@ int coroutine_fn blk_co_pwritev(BlockBackend *blk, in= t64_t offset, typedef struct BlkRwCo { BlockBackend *blk; int64_t offset; - QEMUIOVector *qiov; + void *iobuf; int ret; BdrvRequestFlags flags; } BlkRwCo; @@ -1148,17 +1148,19 @@ typedef struct BlkRwCo { static void blk_read_entry(void *opaque) { BlkRwCo *rwco =3D opaque; + QEMUIOVector *qiov =3D rwco->iobuf; =20 - rwco->ret =3D blk_co_preadv(rwco->blk, rwco->offset, rwco->qiov->size, - rwco->qiov, rwco->flags); + rwco->ret =3D blk_co_preadv(rwco->blk, rwco->offset, qiov->size, + qiov, rwco->flags); } =20 static void blk_write_entry(void *opaque) { BlkRwCo *rwco =3D opaque; + QEMUIOVector *qiov =3D rwco->iobuf; =20 - rwco->ret =3D blk_co_pwritev(rwco->blk, rwco->offset, rwco->qiov->size, - rwco->qiov, rwco->flags); + rwco->ret =3D blk_co_pwritev(rwco->blk, rwco->offset, qiov->size, + qiov, rwco->flags); } =20 static int blk_prw(BlockBackend *blk, int64_t offset, uint8_t *buf, @@ -1178,7 +1180,7 @@ static int blk_prw(BlockBackend *blk, int64_t offset,= uint8_t *buf, rwco =3D (BlkRwCo) { .blk =3D blk, .offset =3D offset, - .qiov =3D &qiov, + .iobuf =3D &qiov, .flags =3D flags, .ret =3D NOT_DONE, }; @@ -1275,7 +1277,7 @@ static void blk_aio_complete_bh(void *opaque) } =20 static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, int byt= es, - QEMUIOVector *qiov, CoroutineEntry co_entr= y, + void *iobuf, CoroutineEntry co_entry, BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque) { @@ -1287,7 +1289,7 @@ static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, in= t64_t offset, int bytes, acb->rwco =3D (BlkRwCo) { .blk =3D blk, .offset =3D offset, - .qiov =3D qiov, + .iobuf =3D iobuf, .flags =3D flags, .ret =3D NOT_DONE, }; @@ -1310,10 +1312,11 @@ static void blk_aio_read_entry(void *opaque) { BlkAioEmAIOCB *acb =3D opaque; BlkRwCo *rwco =3D &acb->rwco; + QEMUIOVector *qiov =3D rwco->iobuf; =20 - assert(rwco->qiov->size =3D=3D acb->bytes); + assert(qiov->size =3D=3D acb->bytes); rwco->ret =3D blk_co_preadv(rwco->blk, rwco->offset, acb->bytes, - rwco->qiov, rwco->flags); + qiov, rwco->flags); blk_aio_complete(acb); } =20 @@ -1321,10 +1324,11 @@ static void blk_aio_write_entry(void *opaque) { BlkAioEmAIOCB *acb =3D opaque; BlkRwCo *rwco =3D &acb->rwco; + QEMUIOVector *qiov =3D rwco->iobuf; =20 - assert(!rwco->qiov || rwco->qiov->size =3D=3D acb->bytes); + assert(!qiov || qiov->size =3D=3D acb->bytes); rwco->ret =3D blk_co_pwritev(rwco->blk, rwco->offset, acb->bytes, - rwco->qiov, rwco->flags); + qiov, rwco->flags); blk_aio_complete(acb); } =20 @@ -1453,8 +1457,10 @@ int blk_co_ioctl(BlockBackend *blk, unsigned long in= t req, void *buf) static void blk_ioctl_entry(void *opaque) { BlkRwCo *rwco =3D opaque; + QEMUIOVector *qiov =3D rwco->iobuf; + rwco->ret =3D blk_co_ioctl(rwco->blk, rwco->offset, - rwco->qiov->iov[0].iov_base); + qiov->iov[0].iov_base); } =20 int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf) @@ -1467,24 +1473,15 @@ static void blk_aio_ioctl_entry(void *opaque) BlkAioEmAIOCB *acb =3D opaque; BlkRwCo *rwco =3D &acb->rwco; =20 - rwco->ret =3D blk_co_ioctl(rwco->blk, rwco->offset, - rwco->qiov->iov[0].iov_base); + rwco->ret =3D blk_co_ioctl(rwco->blk, rwco->offset, rwco->iobuf); + blk_aio_complete(acb); } =20 BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *= buf, BlockCompletionFunc *cb, void *opaque) { - QEMUIOVector qiov; - struct iovec iov; - - iov =3D (struct iovec) { - .iov_base =3D buf, - .iov_len =3D 0, - }; - qemu_iovec_init_external(&qiov, &iov, 1); - - return blk_aio_prwv(blk, req, 0, &qiov, blk_aio_ioctl_entry, 0, cb, op= aque); + return blk_aio_prwv(blk, req, 0, buf, blk_aio_ioctl_entry, 0, cb, opaq= ue); } =20 int blk_co_pdiscard(BlockBackend *blk, int64_t offset, int bytes) @@ -1900,7 +1897,9 @@ int blk_truncate(BlockBackend *blk, int64_t offset, P= reallocMode prealloc, static void blk_pdiscard_entry(void *opaque) { BlkRwCo *rwco =3D opaque; - rwco->ret =3D blk_co_pdiscard(rwco->blk, rwco->offset, rwco->qiov->siz= e); + QEMUIOVector *qiov =3D rwco->iobuf; + + rwco->ret =3D blk_co_pdiscard(rwco->blk, rwco->offset, qiov->size); } =20 int blk_pdiscard(BlockBackend *blk, int64_t offset, int bytes) --=20 2.7.4