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=-10.6 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 3C232C4727C for ; Tue, 29 Sep 2020 21:25:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D667D2075E for ; Tue, 29 Sep 2020 21:25:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="a56Mw4eq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729350AbgI2VZm (ORCPT ); Tue, 29 Sep 2020 17:25:42 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:20067 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727740AbgI2VZm (ORCPT ); Tue, 29 Sep 2020 17:25:42 -0400 Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1601414740; 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=J3Yfdgp8pa810wWFeD1/eInC7Ulkin4K7UvZPCo2vMg=; b=a56Mw4eqnteIaOmLF+EZbSB1k+XrHSbqei3EJTGwSG0hIZD0PGFklrnv5G42+CsvXfzWXy WUkB4Ht8K6LhLgXmdP7k3xhU3/HbfoqRn/56cgaTnKSk0ERVKRUaz6NsYz/zNGb7qZxSBl vkK9yA0Q/UXXYiwacL/kI0zbgFfeGfM= 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-526-Q7jF-_DROkmnbCBidqoBFw-1; Tue, 29 Sep 2020 17:25:38 -0400 X-MC-Unique: Q7jF-_DROkmnbCBidqoBFw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7CCD28018A7; Tue, 29 Sep 2020 21:25:37 +0000 (UTC) Received: from x1.home (ovpn-112-71.phx2.redhat.com [10.3.112.71]) by smtp.corp.redhat.com (Postfix) with ESMTP id E35955D9DC; Tue, 29 Sep 2020 21:25:25 +0000 (UTC) Date: Tue, 29 Sep 2020 15:25:25 -0600 From: Alex Williamson To: guomin_chen@sina.com Cc: Cornelia Huck , Jiang Yi , Marc Zyngier , Peter Xu , Eric Auger , gchen.guomin@gmail.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, mst@redhat.com, jasowang@redhat.com Subject: Re: [PATCH] vfio/pci: when irq_bypass_register_producer() return fails, we need to clean it up and return -EINVAL. instead of return true. Message-ID: <20200929152525.24900f6c@x1.home> In-Reply-To: <20200929145435.7a4fbac9@x1.home> References: <1601208668-6285-1-git-send-email-guomin_chen@sina.com> <20200929145435.7a4fbac9@x1.home> Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 29 Sep 2020 14:54:35 -0600 Alex Williamson wrote: > On Sun, 27 Sep 2020 20:11:08 +0800 > guomin_chen@sina.com wrote: > > > From: guomin chen > > > > Since eventfd "fds" is passed as a parameter by the upper-level > > application,when "fds" has multiple identical 'fd', it causes > > multiple different vfio_pci_irq_ctx->trigger and producer->token > > pointing to the same eventfd file. Although all but the first one > > can register successfully,all others fail to register. > > > > So when others producer released later, the list_del(&producer->node) > > will be called due to the different producer->token pointing to the > > same eventfd file, then triggering the BUG(): > > > > vfio-pci 0000:db:00.0: irq bypass producer (token 0000000060c8cda5) registration fails: -16 > > vfio-pci 0000:db:00.0: irq bypass producer (token 0000000060c8cda5) registration fails: -16 > > vfio-pci 0000:db:00.0: irq bypass producer (token 0000000060c8cda5) registration fails: -16 > > vfio-pci 0000:db:00.0: irq bypass producer (token 0000000060c8cda5) registration fails: -16 > > vfio-pci 0000:db:00.0: irq bypass producer (token 0000000060c8cda5) registration fails: -16 > > list_del corruption, ffff8f7fb8ba0828->next is LIST_POISON1 (dead000000000100) > > ------------[ 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]-/-[7X06CTO1WW]-, > > 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: kvm@vger.kernel.org > > Cc: linux-kernel@vger.kernel.org > > Signed-off-by: guomin chen > > --- > > drivers/vfio/pci/vfio_pci_intrs.c | 15 +++++++++++++-- > > 1 file changed, 13 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c > > index 1d9fb25..dd3a495 100644 > > --- a/drivers/vfio/pci/vfio_pci_intrs.c > > +++ b/drivers/vfio/pci/vfio_pci_intrs.c > > @@ -352,10 +352,21 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev, > > vdev->ctx[vector].producer.token = trigger; > > vdev->ctx[vector].producer.irq = irq; > > ret = irq_bypass_register_producer(&vdev->ctx[vector].producer); > > - if (unlikely(ret)) > > - dev_info(&pdev->dev, > > + if (unlikely(ret)) { > > + dev_err(&pdev->dev, > > "irq bypass producer (token %p) registration fails: %d\n", > > vdev->ctx[vector].producer.token, ret); > > + > > + kfree(vdev->ctx[vector].name); > > + eventfd_ctx_put(trigger); > > + > > + cmd = vfio_pci_memory_lock_and_enable(vdev); > > + free_irq(irq, trigger); > > + vfio_pci_memory_unlock_and_restore(vdev, cmd); > > + > > + vdev->ctx[vector].trigger = NULL; > > + return -EINVAL; > > + } > > > > vdev->ctx[vector].trigger = trigger; > > > > This is not the correct solution. Registering an IRQ bypass is an > accelerator, not a requirement. Failure should never cause the ioctl > to fail. The scenario you describe is a valid user configuration, the > issue is that the de-registration passes a bogus producer object that > was never successfully registered, causing a false match. Therefore I > believe the solution is to simply clear the token on registration > failure to prevent that bogus match. That should result in all the > additional producer objects with the same trigger harmlessly falling > out of the unregister function. Can you validate and post such a > patch? Thanks, BTW, vhost_vdpa_setup_vq_irq() has the same bug (Cc MST & Jason). Thanks, Alex