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avoid race condition between I/O submission in xbd_diskstart() and 

interrupt handling in xbd_handler() - need to protect it with splbio()

fixes PR port-xen/53506 by Emmanuel Dreyfus, and likely also port-xen/53074
by Brad Spencer
This commit is contained in:
jdolecek 2018-08-21 18:11:10 +00:00
parent 70aed070fa
commit 775e33e0fa
1 changed files with 6 additions and 2 deletions
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8
sys/arch/xen/xen/xbd_xenbus.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: xbd_xenbus.c,v 1.82 2018/08/15 15:49:15 jdolecek Exp $ */
/* $NetBSD: xbd_xenbus.c,v 1.83 2018/08/21 18:11:10 jdolecek Exp $ */
/*
* Copyright (c) 2006 Manuel Bouyer.
@ -50,7 +50,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.82 2018/08/15 15:49:15 jdolecek Exp $");
__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.83 2018/08/21 18:11:10 jdolecek Exp $");
#include "opt_xen.h"
@ -932,6 +932,7 @@ xbd_diskstart(device_t self, struct buf *bp)
vaddr_t va;
int nsects, nbytes, seg;
int notify, error = 0;
int s;
DPRINTF(("xbd_diskstart(%p): b_bcount = %ld\n",
bp, (long)bp->b_bcount));
@ -947,6 +948,8 @@ xbd_diskstart(device_t self, struct buf *bp)
goto err;
}
s = splbio(); /* XXX SMP */
if (__predict_false(
sc->sc_backend_status == BLKIF_STATE_SUSPENDED)) {
/* device is suspended, do not consume buffer */
@ -1024,6 +1027,7 @@ out:
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->sc_ring, notify);
if (notify)
hypervisor_notify_via_evtchn(sc->sc_evtchn);
splx(s); /* XXXSMP */
err:
return error;
}