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Make periphdriver_register() take XPT lock when modifying the periph_drivers

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array.

This fixes a panic that sometimes occured when kldloading ctl.ko.

Reviewed by:	mav@
MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
This commit is contained in:
Edward Tomasz Napierala 2015-03-02 22:48:11 +00:00
parent da3b488d62
commit 5719711f8b
2 changed files with 14 additions and 2 deletions
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13
sys/cam/cam_periph.c
View File

@ -108,9 +108,19 @@ periphdriver_register(void *data)
struct periph_driver **newdrivers, **old;
int ndrivers;
again:
ndrivers = nperiph_drivers + 2;
newdrivers = malloc(sizeof(*newdrivers) * ndrivers, M_CAMPERIPH,
M_WAITOK);
xpt_lock_buses();
if (ndrivers != nperiph_drivers + 2) {
/*
* Lost race against itself; go around.
*/
xpt_unlock_buses();
free(newdrivers, M_CAMPERIPH);
goto again;
}
if (periph_drivers)
bcopy(periph_drivers, newdrivers,
sizeof(*newdrivers) * nperiph_drivers);
@ -118,9 +128,10 @@ periphdriver_register(void *data)
newdrivers[nperiph_drivers + 1] = NULL;
old = periph_drivers;
periph_drivers = newdrivers;
nperiph_drivers++;
xpt_unlock_buses();
if (old)
free(old, M_CAMPERIPH);
nperiph_drivers++;
/* If driver marked as early or it is late now, initialize it. */
if (((drv->flags & CAM_PERIPH_DRV_EARLY) != 0 && initialized > 0) ||
initialized > 1)

3
sys/cam/cam_xpt.c
View File

@ -151,6 +151,8 @@ typedef int xpt_pdrvfunc_t (struct periph_driver **pdrv, void *arg);
/* Transport layer configuration information */
static struct xpt_softc xsoftc;
MTX_SYSINIT(xpt_topo_init, &xsoftc.xpt_topo_lock, "XPT topology lock", MTX_DEF);
SYSCTL_INT(_kern_cam, OID_AUTO, boot_delay, CTLFLAG_RDTUN,
&xsoftc.boot_delay, 0, "Bus registration wait time");
SYSCTL_UINT(_kern_cam, OID_AUTO, xpt_generation, CTLFLAG_RD,
@ -850,7 +852,6 @@ xpt_init(void *dummy)
mtx_init(&xsoftc.xpt_lock, "XPT lock", NULL, MTX_DEF);
mtx_init(&xsoftc.xpt_highpower_lock, "XPT highpower lock", NULL, MTX_DEF);
mtx_init(&xsoftc.xpt_topo_lock, "XPT topology lock", NULL, MTX_DEF);
xsoftc.xpt_taskq = taskqueue_create("CAM XPT task", M_WAITOK,
taskqueue_thread_enqueue, /*context*/&xsoftc.xpt_taskq);