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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 EA7BBC433E7 for ; Fri, 9 Oct 2020 18:44:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7666E22284 for ; Fri, 9 Oct 2020 18:44:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ghQCjOZJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733136AbgJISok (ORCPT ); Fri, 9 Oct 2020 14:44:40 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:30177 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731820AbgJISok (ORCPT ); Fri, 9 Oct 2020 14:44:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602269077; 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=vPS9EFQjAPbTsE1U1KE86YkQyoDT5CB+n90O8Fl9QaY=; b=ghQCjOZJxh0gqBwWP5pS4Xo0NM/pw4ob4mG8Yb8gdNMmOpk4JE13fhCvenrZZm/80YsWZU +kLxJgxlzXWFWx3QxO/yPCkFkELEpDSktEjUt0OrRPiuXjaLfY59XAAsmIrOqgPmVul0HZ ErRXP6hDh4sknPn8aqMzKirxThLRwA8= 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-388--yVRXHxjMnKfq6k9hXLnzQ-1; Fri, 09 Oct 2020 14:44:35 -0400 X-MC-Unique: -yVRXHxjMnKfq6k9hXLnzQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 19C5E107B477; Fri, 9 Oct 2020 18:44:34 +0000 (UTC) Received: from x1.home (ovpn-113-35.phx2.redhat.com [10.3.113.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id D7D376266E; Fri, 9 Oct 2020 18:44:24 +0000 (UTC) Date: Fri, 9 Oct 2020 12:44:23 -0600 From: Alex Williamson To: gchen chen Cc: guomin_chen@sina.com, Cornelia Huck , Jiang Yi , Marc Zyngier , Peter Xu , Eric Auger , "Michael S. Tsirkin" , Jason Wang , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] irqbypass: fix error handle when irq_bypass_register_producer() return fails Message-ID: <20201009124423.2a8603f7@x1.home> In-Reply-To: References: <1601470479-26848-1-git-send-email-guomin_chen@sina.com> <20200930080919.1a9c66f8@x1.home> Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 9 Oct 2020 12:30:04 +0800 gchen chen wrote: > Alex Williamson =E4=BA=8E2020=E5=B9=B49=E6= =9C=8830=E6=97=A5=E5=91=A8=E4=B8=89 =E4=B8=8B=E5=8D=8810:09=E5=86=99=E9=81= =93=EF=BC=9A > > > > > > Please version your postings so we know which one to consider as the > > current proposal. > > > > On Wed, 30 Sep 2020 20:54:39 +0800 > > guomin_chen@sina.com wrote: > > =20 > > > From: guomin chen > > > > > > When the producer object registration fails,In the future, due to > > > incorrect matching when unregistering, list_del(&producer->node) > > > may still be called, then trigger a BUG: > > > > > > vfio-pci 0000:db:00.0: irq bypass producer (token 0000000060c8cda= 5) registration fails: -16 > > > vfio-pci 0000:db:00.0: irq bypass producer (token 0000000060c8cda= 5) registration fails: -16 > > > vfio-pci 0000:db:00.0: irq bypass producer (token 0000000060c8cda= 5) registration fails: -16 > > > ... > > > list_del corruption, ffff8f7fb8ba0828->next is LIST_POISON1 (dead= 000000000100) > > > ------------[ cut here ]------------ > > > kernel BUG at lib/list_debug.c:47! > > > invalid opcode: 0000 [#1] SMP NOPTI > > > CPU: 29 PID: 3914 Comm: qemu-kvm Kdump: loaded Tainted: G E > > > -------- - -4.18.0-193.6.3.el8.x86_64 #1 > > > Hardware name: Lenovo ThinkSystem SR650 -[7X06CTO1WW]-/-[7X06CTO1= WW]-, > > > BIOS -[IVE636Z-2.13]- 07/18/2019 > > > RIP: 0010:__list_del_entry_valid.cold.1+0x12/0x4c > > > Code: ce ff 0f 0b 48 89 c1 4c 89 c6 48 c7 c7 40 85 4d 88 e8 8c bc > > > ce ff 0f 0b 48 89 fe 48 89 c2 48 c7 c7 d0 85 4d 88 e8 78 bc > > > ce ff <0f> 0b 48 c7 c7 80 86 4d 88 e8 6a bc ce ff 0f 0b 48 > > > 89 f2 48 89 fe > > > RSP: 0018:ffffaa9d60197d20 EFLAGS: 00010246 > > > RAX: 000000000000004e RBX: ffff8f7fb8ba0828 RCX: 0000000000000000 > > > RDX: 0000000000000000 RSI: ffff8f7fbf4d6a08 RDI: ffff8f7fbf4d6a08 > > > RBP: 0000000000000000 R08: 000000000000084b R09: 000000000000005d > > > R10: 0000000000000000 R11: ffffaa9d60197bd0 R12: ffff8f4fbe863000 > > > R13: 00000000000000c2 R14: 0000000000000000 R15: 0000000000000000 > > > FS: 00007f7cb97fa700(0000) GS:ffff8f7fbf4c0000(0000) > > > knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: 00007fcf31da4000 CR3: 0000005f6d404001 CR4: 00000000007626e0 > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > PKRU: 55555554 > > > Call Trace: > > > irq_bypass_unregister_producer+0x9b/0xf0 [irqbypass] > > > vfio_msi_set_vector_signal+0x8c/0x290 [vfio_pci] > > > ? load_fixmap_gdt+0x22/0x30 > > > vfio_msi_set_block+0x6e/0xd0 [vfio_pci] > > > vfio_pci_ioctl+0x218/0xbe0 [vfio_pci] > > > ? kvm_vcpu_ioctl+0xf2/0x5f0 [kvm] > > > do_vfs_ioctl+0xa4/0x630 > > > ? syscall_trace_enter+0x1d3/0x2c0 > > > ksys_ioctl+0x60/0x90 > > > __x64_sys_ioctl+0x16/0x20 > > > do_syscall_64+0x5b/0x1a0 > > > entry_SYSCALL_64_after_hwframe+0x65/0xca > > > > > > Cc: Alex Williamson > > > Cc: Cornelia Huck > > > Cc: Jiang Yi > > > Cc: Marc Zyngier > > > Cc: Peter Xu > > > Cc: Eric Auger > > > Cc: "Michael S. Tsirkin" > > > Cc: Jason Wang > > > Cc: kvm@vger.kernel.org > > > Cc: linux-kernel@vger.kernel.org > > > Signed-off-by: guomin chen > > > --- > > > drivers/vfio/pci/vfio_pci_intrs.c | 13 +++++++++++-- > > > drivers/vhost/vdpa.c | 7 +++++++ > > > 2 files changed, 18 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfi= o_pci_intrs.c > > > index 1d9fb25..c371943 100644 > > > --- a/drivers/vfio/pci/vfio_pci_intrs.c > > > +++ b/drivers/vfio/pci/vfio_pci_intrs.c > > > @@ -352,12 +352,21 @@ static int vfio_msi_set_vector_signal(struct vf= io_pci_device *vdev, > > > vdev->ctx[vector].producer.token =3D trigger; > > > vdev->ctx[vector].producer.irq =3D irq; > > > ret =3D irq_bypass_register_producer(&vdev->ctx[vector].produce= r); > > > - if (unlikely(ret)) > > > + if (unlikely(ret)) { > > > dev_info(&pdev->dev, > > > "irq bypass producer (token %p) registration fails: %d\= n", > > > vdev->ctx[vector].producer.token, ret); > > > > > > - vdev->ctx[vector].trigger =3D trigger; > > > + kfree(vdev->ctx[vector].name); > > > + eventfd_ctx_put(trigger); > > > + > > > + cmd =3D vfio_pci_memory_lock_and_enable(vdev); > > > + free_irq(irq, trigger); > > > + vfio_pci_memory_unlock_and_restore(vdev, cmd); > > > + > > > + vdev->ctx[vector].trigger =3D NULL; > > > + } else > > > + vdev->ctx[vector].trigger =3D trigger; > > > > > > return 0; > > > } =20 > > > > Once again, the irq bypass registration cannot cause the vector setup > > to fail, either by returning an error code or failing to configure the > > vector while returning success. It's my assertion that we simply need > > to set the producer.token to NULL on failure such that unregistering > > the producer will not generate a match, as you've done below. The > > vector still works even if this registration fails. > > =20 > Yes, the irq bypass registration cannot cause the vector setup to fail. > But if I simply set producer.token to NULL when fails, instead of > cleaning up vector, it will trigger the following BUG: >=20 > vfio_ecap_init: 0000:db:00.0 hiding ecap 0x1e@0x310 > vfio-pci 0000:db:00.0: irq bypass producer (token 000000004409229f) > registration fails: -16 > ------------[ cut here ]------------ > kernel BUG at drivers/pci/msi.c:352! > invalid opcode: 0000 [#1] SMP NOPTI > CPU: 55 PID: 9389 Comm: qemu-kvm Kdump: loaded Tainted: G > E --------- - - 4.18.0-193.irqb.r1.el8.x86_64 #1 > Hardware name: Lenovo ThinkSystem SR650 -[7X06CTO1WW]-/-[7X06CTO1WW]-, > BIOS -[IVE636Z-2.13]- 07/18/2019 > RIP: 0010:free_msi_irqs+0x180/0x1b0 > Code: 14 85 c0 0f 84 d5 fe ff ff 31 ed eb 0f 83 c5 01 39 6b 14 0f 86 > c5 fe ff ff 8b 7b 10 01 ef e8 d7 4a c9 ff 48 83 78 70 00 74 e3 > <0f> 0b 49 8d b5 b0 00 00 00 e8 e2 e3 c9 ff e9 c7 fe ff ff 48 > 8b 7b > RSP: 0018:ffffaeca4f4bfcd8 EFLAGS: 00010286 > RAX: ffff8bec77441600 RBX: ffff8bbcdb637e40 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: 00000000000001ab RDI: ffffffff8ea5b2a0 > RBP: 0000000000000000 R08: ffff8bec7e746828 R09: ffff8bec7e7466a8 > R10: 0000000000000000 R11: 0000000000000000 R12: ffff8bbcde921308 > R13: ffff8bbcde921000 R14: 000000000000000b R15: 0000000000000021 > FS: 00007fd18d7fa700(0000) GS:ffff8bec7f6c0000(0000) knlGS:0000000000000= 000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f83650024a0 CR3: 000000476e70c001 CR4: 00000000007626e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > PKRU: 55555554 > Call Trace: > pci_disable_msix+0xf3/0x120 > pci_free_irq_vectors+0xe/0x20 > vfio_msi_disable+0x89/0xd0 [vfio_pci] > vfio_pci_set_msi_trigger+0x229/0x2d0 [vfio_pci] > vfio_pci_ioctl+0x24f/0xdb0 [vfio_pci] > ? pollwake+0x74/0x90 > ? wake_up_q+0x70/0x70 > do_vfs_ioctl+0xa4/0x630 > ? __alloc_fd+0x33/0x140 > ? syscall_trace_enter+0x1d3/0x2c0 > ksys_ioctl+0x60/0x90 > __x64_sys_ioctl+0x16/0x20 > do_syscall_64+0x5b/0x1a0 > entry_SYSCALL_64_after_hwframe+0x65/0xca Please post the patch that triggers this, I'm not yet convinced we're speaking of the same solution. The user ioctl cannot fail due to the failure to setup a bypass accelerator, nor can the ioctl return success without configuring all of the user requested vectors, which is what I understand the v2 patch above to do. We simply want to configure the failed producer such that when we unregister it at user request, we avoid creating a bogus match. It's not apparent to me why doing that would cause any changes to the setup or teardown of the MSI vector in PCI code. Thanks, Alex