From 29bfe2102d6c65f96ef46ea2660f2a3af0a57ed1 Mon Sep 17 00:00:00 2001 From: Kristof Provost Date: Wed, 8 Jan 2020 10:06:32 +0000 Subject: [PATCH] vtnet: Pre-allocate debugnet data immediately Don't wait until the vtnet_debugnet_init() call happens, because at that point we might already have allocated something from vtnet_tx_header_zone. Some systems showed this panic: vtnet0: link state changed to UP panic: keg vtnet_tx_hdr initialization after use. cpuid = 5 time = 1578427700 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe004db427f0 vpanic() at vpanic+0x17e/frame 0xfffffe004db42850 panic() at panic+0x43/frame 0xfffffe004db428b0 uma_zone_reserve() at uma_zone_reserve+0xf6/frame 0xfffffe004db428f0 vtnet_debugnet_init() at vtnet_debugnet_init+0x77/frame 0xfffffe004db42930 debugnet_any_ifnet_update() at debugnet_any_ifnet_update+0x42/frame 0xfffffe004db42980 do_link_state_change() at do_link_state_change+0x1b3/frame 0xfffffe004db429d0 taskqueue_run_locked() at taskqueue_run_locked+0x178/frame 0xfffffe004db42a30 taskqueue_run() at taskqueue_run+0x4d/frame 0xfffffe004db42a50 ithread_loop() at ithread_loop+0x1d6/frame 0xfffffe004db42ab0 fork_exit() at fork_exit+0x80/frame 0xfffffe004db42af0 fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe004db42af0 --- trap 0, rip = 0, rsp = 0, rbp = 0 --- KDB: enter: panic [ thread pid 12 tid 100011 ] Stopped at kdb_enter+0x37: movq $0,0x1084eb6(%rip) db> Reviewed by: cem, markj Differential Revision: https://reviews.freebsd.org/D23073 --- sys/dev/virtio/network/if_vtnet.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/sys/dev/virtio/network/if_vtnet.c b/sys/dev/virtio/network/if_vtnet.c index ee3c2310f2da..bf74875ac1ab 100644 --- a/sys/dev/virtio/network/if_vtnet.c +++ b/sys/dev/virtio/network/if_vtnet.c @@ -337,10 +337,21 @@ vtnet_modevent(module_t mod, int type, void *unused) switch (type) { case MOD_LOAD: - if (loaded++ == 0) + if (loaded++ == 0) { vtnet_tx_header_zone = uma_zcreate("vtnet_tx_hdr", sizeof(struct vtnet_tx_header), NULL, NULL, NULL, NULL, 0, 0); +#ifdef DEBUGNET + /* + * We need to allocate from this zone in the transmit path, so ensure + * that we have at least one item per header available. + * XXX add a separate zone like we do for mbufs? otherwise we may alloc + * buckets + */ + uma_zone_reserve(vtnet_tx_header_zone, DEBUGNET_MAX_IN_FLIGHT * 2); + uma_prealloc(vtnet_tx_header_zone, DEBUGNET_MAX_IN_FLIGHT * 2); +#endif + } break; case MOD_QUIESCE: if (uma_zone_get_cur(vtnet_tx_header_zone) > 0) @@ -3982,15 +3993,6 @@ vtnet_debugnet_init(struct ifnet *ifp, int *nrxr, int *ncl, int *clsize) *ncl = DEBUGNET_MAX_IN_FLIGHT; *clsize = sc->vtnet_rx_clsize; VTNET_CORE_UNLOCK(sc); - - /* - * We need to allocate from this zone in the transmit path, so ensure - * that we have at least one item per header available. - * XXX add a separate zone like we do for mbufs? otherwise we may alloc - * buckets - */ - uma_zone_reserve(vtnet_tx_header_zone, DEBUGNET_MAX_IN_FLIGHT * 2); - uma_prealloc(vtnet_tx_header_zone, DEBUGNET_MAX_IN_FLIGHT * 2); } static void