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vtnet: Pre-allocate debugnet data immediately

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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
This commit is contained in:
Kristof Provost 2020-01-08 10:06:32 +00:00
parent 2138e99bf5
commit 29bfe2102d
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=356484
1 changed files with 12 additions and 10 deletions
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22
sys/dev/virtio/network/if_vtnet.c
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@ -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