From a747fd2cf184031fedccff9fc0e7fb31d7d5cab8 Mon Sep 17 00:00:00 2001 From: Roger Pau Monne Date: Thu, 19 Jun 2014 13:06:05 +0200 Subject: [PATCH v5 29/29] xen: fix netback disconnect issues Netback disconnect performed in xnb_shutdown was not taking the required lock when modifying xnb->carrier, which is guarded by the rx_lock. Also, make sure the xnb_disconnect disconnect is performed before shutting down the interface. This fix prevents the following panic: Kernel page fault with the following non-sleepable locks held: exclusive sleep mutex if_bridge (if_bridge) r = 0 (0xfffff80006306c18) locked @ /usr/src/sys/modules/if_bridge/../../net/if_bridge.c:2260 KDB: stack backtrace: X_db_symbol_values() at X_db_symbol_values+0x10b/frame 0xfffffe0000213490 kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe0000213540 witness_warn() at witness_warn+0x4a8/frame 0xfffffe0000213600 trap() at trap+0xc9d/frame 0xfffffe00002136a0 trap() at trap+0x669/frame 0xfffffe00002138b0 calltrap() at calltrap+0x8/frame 0xfffffe00002138b0 --- trap 0xc, rip = 0xffffffff8221a0ef, rsp = 0xfffffe0000213970, rbp = 0xfffffe00002139e0 --- bridge_input() at bridge_input+0x5ff/frame 0xfffffe00002139e0 ether_vlanencap() at ether_vlanencap+0x4a3/frame 0xfffffe0000213a10 netisr_dispatch_src() at netisr_dispatch_src+0x90/frame 0xfffffe0000213a80 ether_ifattach() at ether_ifattach+0x19f/frame 0xfffffe0000213ab0 ath_dfs_get_thresholds() at ath_dfs_get_thresholds+0x81ce/frame 0xfffffe0000213b30 intr_event_execute_handlers() at intr_event_execute_handlers+0x93/frame 0xfffffe0000213b70 db_dump_intr_event() at db_dump_intr_event+0x796/frame 0xfffffe0000213bb0 fork_exit() at fork_exit+0x84/frame 0xfffffe0000213bf0 fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe0000213bf0 --- trap 0, rip = 0, rsp = 0xfffffe0000213cb0, rbp = 0 --- Sponsored by: Citrix Systems R&D Approved by: xxx dev/xen/netback/netback.c: - Take the rx_lock when modifying xnb->carrier. - Disconnect the interface before removing it. --- sys/dev/xen/netback/netback.c | 9 ++++++--- 1 files changed, 6 insertions(+), 3 deletions(-) diff --git a/sys/dev/xen/netback/netback.c b/sys/dev/xen/netback/netback.c index 9097140..a8bec76 100644 --- a/sys/dev/xen/netback/netback.c +++ b/sys/dev/xen/netback/netback.c @@ -1073,9 +1073,14 @@ xnb_shutdown(struct xnb_softc *xnb) xnb->flags |= XNBF_IN_SHUTDOWN; + mtx_lock(&xnb->rx_lock); + xnb->carrier = 0; + mtx_unlock(&xnb->rx_lock); + + xnb_disconnect(xnb); + mtx_unlock(&xnb->sc_lock); /* Free the network interface */ - xnb->carrier = 0; if (xnb->xnb_ifp != NULL) { ether_ifdetach(xnb->xnb_ifp); if_free(xnb->xnb_ifp); @@ -1083,8 +1088,6 @@ xnb_shutdown(struct xnb_softc *xnb) } 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); -- 1.7.7.5 (Apple Git-26)