From owner-dev-commits-src-main@freebsd.org Tue Sep 7 04:45:51 2021 Return-Path: Delivered-To: dev-commits-src-main@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 700BD6A8775; Tue, 7 Sep 2021 04:45:51 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4H3XlM2Dhgz3jty; Tue, 7 Sep 2021 04:45:51 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 2DF3043BA; Tue, 7 Sep 2021 04:45:51 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 1874jpxO095109; Tue, 7 Sep 2021 04:45:51 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 1874jp9A095108; Tue, 7 Sep 2021 04:45:51 GMT (envelope-from git) Date: Tue, 7 Sep 2021 04:45:51 GMT Message-Id: <202109070445.1874jp9A095108@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Kevin Bowling Subject: git: 8270b7174c48 - main - ixgbe: fix infinite recursion on PCIe link down MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: kbowling X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 8270b7174c48417a4d5f3effa4a4f4588205e687 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-main@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for the main branch of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 07 Sep 2021 04:45:51 -0000 The branch main has been updated by kbowling (ports committer): URL: https://cgit.FreeBSD.org/src/commit/?id=8270b7174c48417a4d5f3effa4a4f4588205e687 commit 8270b7174c48417a4d5f3effa4a4f4588205e687 Author: Guinan Sun AuthorDate: 2020-07-09 08:00:31 +0000 Commit: Kevin Bowling CommitDate: 2021-09-07 02:22:11 +0000 ixgbe: fix infinite recursion on PCIe link down In some corner cases the functions ixgbe_clear_rar_generic and ixgbe_clear_vmdq_generic may call one another leading to infinite recursion. When ixgbe_clear_vmdq_generic is called with IXGBE_CLEAR_VMDQ_ALL flag, it's going to clear MPSAR registers, and proceed to call ixgbe_clear_rar_generic, which in turn will clear the RAR registers, and recursively call back ixgbe_clear_vmdq_generic. Normally, the latter would detect that MPSAR registers have already been cleared and terminate the recursion. However, when PCIe link is down, and before the driver has had the opportunity to shut itself down, all register reads return 0xFFFFFFFF, and all register writes fail silently. In such case, because ixgbe_clear_vmdq_generic blindly assumes that clearing MPSAR registers succeeded, it's going to always call ixgbe_clear_rar_generic, which in turn will always call back ixgbe_clear_vmdq_generic, creating infinite recursion. This patch re-reads MPSAR register values after they had been cleared. In case of PCIe link failure, the values read will be non-zero, which will terminate the recursion. On the other hand, under normal circumstances the value read from MPSAR registers is going to be equal to the value previously written, so this patch is expected not to cause any regressions. Signed-off-by: Robert Konklewski Signed-off-by: Guinan Sun Reviewed-by: Wei Zhao Approved by: imp Obtained from: DPDK (2d04b9e856125197ec8e967471426d56ab7efcf0) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D31621 --- sys/dev/ixgbe/ixgbe_common.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/sys/dev/ixgbe/ixgbe_common.c b/sys/dev/ixgbe/ixgbe_common.c index d7da9f81fbf8..92db7c14da45 100644 --- a/sys/dev/ixgbe/ixgbe_common.c +++ b/sys/dev/ixgbe/ixgbe_common.c @@ -3813,11 +3813,11 @@ s32 ixgbe_clear_vmdq_generic(struct ixgbe_hw *hw, u32 rar, u32 vmdq) if (vmdq == IXGBE_CLEAR_VMDQ_ALL) { if (mpsar_lo) { IXGBE_WRITE_REG(hw, IXGBE_MPSAR_LO(rar), 0); - mpsar_lo = 0; + mpsar_lo = IXGBE_READ_REG(hw, IXGBE_MPSAR_LO(rar)); } if (mpsar_hi) { IXGBE_WRITE_REG(hw, IXGBE_MPSAR_HI(rar), 0); - mpsar_hi = 0; + mpsar_hi = IXGBE_READ_REG(hw, IXGBE_MPSAR_HI(rar)); } } else if (vmdq < 32) { mpsar_lo &= ~(1 << vmdq);