Date: Tue, 26 Jun 2018 14:07:11 +0000 (UTC) From: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= <royger@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r335664 - head/sys/dev/xen/netback Message-ID: <201806261407.w5QE7B2Q044176@repo.freebsd.org>
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Author: royger Date: Tue Jun 26 14:07:11 2018 New Revision: 335664 URL: https://svnweb.freebsd.org/changeset/base/335664 Log: xen-netback: fix LOR lock order reversal: (sleepable after non-sleepable) 1st 0xfffffe00357ff538 xnb_softc (xen netback softc lock) @ /usr/src/sys/dev/xen/netback/netback.c:1069 2nd 0xffffffff81fdccb0 intrsrc (intrsrc) @ /usr/src/sys/x86/x86/intr_machdep.c:224 There's no need to hold the lock since the cleaning of the interrupt cannot happen in parallel due to the XNBF_IN_SHUTDOWN flag being set. Note that the locking in netback needs some improvement or clarification. While there also remove a double newline. Sponsored by: Citrix Systems R&D Modified: head/sys/dev/xen/netback/netback.c Modified: head/sys/dev/xen/netback/netback.c ============================================================================== --- head/sys/dev/xen/netback/netback.c Tue Jun 26 14:01:03 2018 (r335663) +++ head/sys/dev/xen/netback/netback.c Tue Jun 26 14:07:11 2018 (r335664) @@ -662,6 +662,7 @@ xnb_disconnect(struct xnb_softc *xnb) mtx_lock(&xnb->rx_lock); mtx_unlock(&xnb->rx_lock); + mtx_lock(&xnb->sc_lock); /* Free malloc'd softc member variables */ if (xnb->bridge != NULL) { free(xnb->bridge, M_XENSTORE); @@ -689,6 +690,8 @@ xnb_disconnect(struct xnb_softc *xnb) sizeof(struct xnb_ring_config)); xnb->flags &= ~XNBF_RING_CONNECTED; + mtx_unlock(&xnb->sc_lock); + return (0); } @@ -1066,17 +1069,14 @@ xnb_shutdown(struct xnb_softc *xnb) if_free(xnb->xnb_ifp); xnb->xnb_ifp = NULL; } - mtx_lock(&xnb->sc_lock); xnb_disconnect(xnb); - mtx_unlock(&xnb->sc_lock); if (xenbus_get_state(xnb->dev) < XenbusStateClosing) xenbus_set_state(xnb->dev, XenbusStateClosing); mtx_lock(&xnb->sc_lock); xnb->flags &= ~XNBF_IN_SHUTDOWN; - /* Indicate to xnb_detach() that is it safe to proceed. */ wakeup(xnb);
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