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Commit 83292e0a authored by David S. Miller's avatar David S. Miller
Browse files

[SPARC64]: Fix MD property lifetime bugs. 



Property values cannot be referenced outside of
mdesc_grab()/mdesc_release() pairs.  The only major
offender was the VIO bus layer, easily fixed.

Add some commentary to mdesc.h describing these rules.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 43fdf274

arch/sparc64/kernel/vio.c

+28 −11
Original line number Diff line number Diff line
@@ -44,12 +44,11 @@ static const struct vio_device_id *vio_match_device( 


	while (matches->type[0] || matches->compat[0]) {

		int match = 1;

		if (matches->type[0]) {

			match &= type

				&& !strcmp(matches->type, type);

		}

		if (matches->type[0])

			match &= !strcmp(matches->type, type);



		if (matches->compat[0]) {

			match &= compat &&

			match &= len &&

				find_in_proplist(compat, matches->compat, len);

		}

		if (match)
@@ -205,15 +204,30 @@ static struct vio_dev *vio_create_one(struct mdesc_handle *hp, u64 mp, 
	const char *type, *compat;

	struct device_node *dp;

	struct vio_dev *vdev;

	int err, clen;

	int err, tlen, clen;



	type = mdesc_get_property(hp, mp, "device-type", NULL);

	type = mdesc_get_property(hp, mp, "device-type", &tlen);

	if (!type) {

		type = mdesc_get_property(hp, mp, "name", &tlen);

		if (!type) {

		type = mdesc_get_property(hp, mp, "name", NULL);

		if (!type)

			type = mdesc_node_name(hp, mp);

			tlen = strlen(type) + 1;

		}

	}

	if (tlen > VIO_MAX_TYPE_LEN) {

		printk(KERN_ERR "VIO: Type string [%s] is too long.\n",

		       type);

		return NULL;

	}



	compat = mdesc_get_property(hp, mp, "device-type", &clen);

	if (!compat) {

		clen = 0;

	} else if (clen > VIO_MAX_COMPAT_LEN) {

		printk(KERN_ERR "VIO: Compat len %d for [%s] is too long.\n",

		       clen, type);

		return NULL;

	}



	vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);

	if (!vdev) {
@@ -222,8 +236,11 @@ static struct vio_dev *vio_create_one(struct mdesc_handle *hp, u64 mp, 
	}



	vdev->mp = mp;

	vdev->type = type;

	vdev->compat = compat;

	memcpy(vdev->type, type, tlen);

	if (compat)

		memcpy(vdev->compat, compat, clen);

	else

		memset(vdev->compat, 0, sizeof(vdev->compat));

	vdev->compat_len = clen;



	vdev->channel_id = ~0UL;

include/asm-sparc64/mdesc.h

+20 −2
Original line number Diff line number Diff line
@@ -23,8 +23,28 @@ extern u64 mdesc_node_by_name(struct mdesc_handle *handle, 
	     (__node) != MDESC_NODE_NULL; \

	     __node = mdesc_node_by_name(__hdl, __node, __name))



/* Access to property values returned from mdesc_get_property() are

 * only valid inside of a mdesc_grab()/mdesc_release() sequence.

 * Once mdesc_release() is called, the memory backed up by these

 * pointers may reference freed up memory.

 *

 * Therefore callers must make copies of any property values

 * they need.

 *

 * These same rules apply to mdesc_node_name().

 */

extern const void *mdesc_get_property(struct mdesc_handle *handle,

				      u64 node, const char *name, int *lenp);

extern const char *mdesc_node_name(struct mdesc_handle *hp, u64 node);



/* MD arc iteration, the standard sequence is:

 *

 *	unsigned long arc;

 *	mdesc_for_each_arc(arc, handle, node, MDESC_ARC_TYPE_{FWD,BACK}) {

 *		unsigned long target = mdesc_arc_target(handle, arc);

 *		...

 *	}

 */



#define MDESC_ARC_TYPE_FWD	"fwd"

#define MDESC_ARC_TYPE_BACK	"back"
@@ -38,8 +58,6 @@ extern u64 mdesc_next_arc(struct mdesc_handle *handle, u64 from, 


extern u64 mdesc_arc_target(struct mdesc_handle *hp, u64 arc);



extern const char *mdesc_node_name(struct mdesc_handle *hp, u64 node);



extern void mdesc_update(void);



extern void sun4v_mdesc_init(void);

include/asm-sparc64/vio.h

+5 −2
Original line number Diff line number Diff line
@@ -264,12 +264,15 @@ static inline u32 vio_dring_avail(struct vio_dring_state *dr, 
		((dr->prod - dr->cons) & (ring_size - 1)));

}



#define VIO_MAX_TYPE_LEN	64

#define VIO_MAX_COMPAT_LEN	64



struct vio_dev {

	u64			mp;

	struct device_node	*dp;



	const char		*type;

	const char		*compat;

	char			type[VIO_MAX_TYPE_LEN];

	char			compat[VIO_MAX_COMPAT_LEN];

	int			compat_len;



	unsigned long		channel_id;