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Mon, 20 Jul 2020 06:01:59 -0400 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-101-zag3b9fSN36rLsDeDRpKgQ-1; Mon, 20 Jul 2020 06:01:48 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 43057193F567; Mon, 20 Jul 2020 10:01:47 +0000 (UTC) Received: from localhost (ovpn-114-38.ams2.redhat.com [10.36.114.38]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3CF8D87303; Mon, 20 Jul 2020 10:01:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595239312; 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; bh=IYFN08AFXnRWf+5Ps86TQXspIdKFqgDww/qh8IKOHss=; b=P8kpOS2GMBhMSw1iOIPT7vJATp1A3r276+IfW89NGXLULMBGdqsT1sbjuB7wgzkLDbHDP4 CuYZAPZeC62fhMw3jQVHTi7wdvpOSax76OIxM551aOp7ZarKDpFImHDM0BaPBwR53g3cGe PS1AeNhXWAJOCo7Gjx1vQFel3ULZUyo= X-MC-Unique: zag3b9fSN36rLsDeDRpKgQ-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH for-5.1] block: fix bdrv_aio_cancel() for ENOMEDIUM requests Date: Mon, 20 Jul 2020 11:01:41 +0100 Message-Id: <20200720100141.129739-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=stefanha@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=207.211.31.120; envelope-from=stefanha@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/20 03:17:01 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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: Kevin Wolf , qemu-block@nongnu.org, qemu-stable@nongnu.org, Max Reitz , Alexander Bulekov , Stefan Hajnoczi , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" bdrv_aio_cancel() calls aio_poll() on the AioContext for the given I/O request until it has completed. ENOMEDIUM requests are special because there is no BlockDriverState when the drive has no medium! Define a .get_aio_context() function for BlkAioEmAIOCB requests so that bdrv_aio_cancel() can find the AioContext where the completion BH is pending. Without this function bdrv_aio_cancel() aborts on ENOMEDIUM requests! libFuzzer triggered the following assertion: cat << EOF | qemu-system-i386 -M pc-q35-5.0 \ -nographic -monitor none -serial none \ -qtest stdio -trace ide\* outl 0xcf8 0x8000fa24 outl 0xcfc 0xe106c000 outl 0xcf8 0x8000fa04 outw 0xcfc 0x7 outl 0xcf8 0x8000fb20 write 0x0 0x3 0x2780e7 write 0xe106c22c 0xd 0x1130c218021130c218021130c2 write 0xe106c218 0x15 0x110010110010110010110010110010110010110010 EOF ide_exec_cmd IDE exec cmd: bus 0x56170a77a2b8; state 0x56170a77a340; cmd = 0xe7 ide_reset IDEstate 0x56170a77a340 Aborted (core dumped) (gdb) bt #1 0x00007ffff4f93895 in abort () at /lib64/libc.so.6 #2 0x0000555555dc6c00 in bdrv_aio_cancel (acb=3D0x555556765550) at block= /io.c:2745 #3 0x0000555555dac202 in blk_aio_cancel (acb=3D0x555556765550) at block/= block-backend.c:1546 #4 0x0000555555b1bd74 in ide_reset (s=3D0x555557213340) at hw/ide/core.c= :1318 #5 0x0000555555b1e3a1 in ide_bus_reset (bus=3D0x5555572132b8) at hw/ide/= core.c:2422 #6 0x0000555555b2aa27 in ahci_reset_port (s=3D0x55555720eb50, port=3D2) = at hw/ide/ahci.c:650 #7 0x0000555555b29fd7 in ahci_port_write (s=3D0x55555720eb50, port=3D2, = offset=3D44, val=3D16) at hw/ide/ahci.c:360 #8 0x0000555555b2a564 in ahci_mem_write (opaque=3D0x55555720eb50, addr= =3D556, val=3D16, size=3D1) at hw/ide/ahci.c:513 #9 0x000055555598415b in memory_region_write_accessor (mr=3D0x55555720eb= 80, addr=3D556, value=3D0x7fffffffb838, size=3D1, shift=3D0, mask=3D255, at= trs=3D...) at softmmu/memory.c:483 Looking at bdrv_aio_cancel: 2728 /* async I/Os */ 2729 2730 void bdrv_aio_cancel(BlockAIOCB *acb) 2731 { 2732 qemu_aio_ref(acb); 2733 bdrv_aio_cancel_async(acb); 2734 while (acb->refcnt > 1) { 2735 if (acb->aiocb_info->get_aio_context) { 2736 aio_poll(acb->aiocb_info->get_aio_context(acb), true); 2737 } else if (acb->bs) { 2738 /* qemu_aio_ref and qemu_aio_unref are not thread-safe, so 2739 * assert that we're not using an I/O thread. Thread-safe 2740 * code should use bdrv_aio_cancel_async exclusively. 2741 */ 2742 assert(bdrv_get_aio_context(acb->bs) =3D=3D qemu_get_aio_c= ontext()); 2743 aio_poll(bdrv_get_aio_context(acb->bs), true); 2744 } else { 2745 abort(); <=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D 2746 } 2747 } 2748 qemu_aio_unref(acb); 2749 } Fixes: 02c50efe08736116048d5fc355043080f4d5859c ("block: Add bdrv_aio_cance= l_async") Reported-by: Alexander Bulekov Buglink: https://bugs.launchpad.net/qemu/+bug/1878255 Originally-by: Philippe Mathieu-Daud=C3=A9 Signed-off-by: Stefan Hajnoczi --- block/block-backend.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/block/block-backend.c b/block/block-backend.c index 0bf0188133..3a13cb5f0b 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -1394,8 +1394,16 @@ typedef struct BlkAioEmAIOCB { bool has_returned; } BlkAioEmAIOCB; =20 +static AioContext *blk_aio_em_aiocb_get_aio_context(BlockAIOCB *acb_) +{ + BlkAioEmAIOCB *acb =3D container_of(acb_, BlkAioEmAIOCB, common); + + return blk_get_aio_context(acb->rwco.blk); +} + static const AIOCBInfo blk_aio_em_aiocb_info =3D { .aiocb_size =3D sizeof(BlkAioEmAIOCB), + .get_aio_context =3D blk_aio_em_aiocb_get_aio_context, }; =20 static void blk_aio_complete(BlkAioEmAIOCB *acb) --=20 2.26.2