Skip to contentSkip to conversation

Patch "cls_u32: add missing RCU annotation." has been added to the 4.15-stable tree

PATCH [email protected] 1 participant 1 message Feb 7, 2018

Subsystems (3)
Networking Stable branch Traffic control (tc)
lore
Share & tools
lore

[email protected]

author maintainer Applied
#0 lore raw

This is a note to let you know that I've just added the patch titled

cls_u32: add missing RCU annotation.

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
cls_u32-add-missing-rcu-annotation.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From foo@baz Wed Feb 7 11:29:33 PST 2018

From: Paolo Abeni <[email protected]>
Date: Fri, 2 Feb 2018 16:02:22 +0100
Subject: cls_u32: add missing RCU annotation.

From: Paolo Abeni <[email protected]>

[ Upstream commit 058a6c033488494a6b1477b05fe8e1a16e344462 ]

In a couple of points of the control path, n->ht_down is currently accessed without the required RCU annotation. The accesses are safe, but sparse complaints. Since we already held the rtnl lock, let use rtnl_dereference().

Fixes a1b7c5fd7fe9 ("net: sched: add cls_u32 offload hooks for netdevs")
Fixes de5df63228fc ("net: sched: cls_u32 changes to knode must appear atomic to readers")
Signed-off-by Paolo Abeni <[email protected]>
Acked-by Cong Wang <[email protected]>
Signed-off-by David S. Miller <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 net/sched/cls_u32.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)
net/sched/cls_u32.c +7 -5
@@ -544,6 +544,7 @@ static void u32_remove_hw_knode(struct t
 static int u32_replace_hw_knode(struct tcf_proto *tp, struct tc_u_knode *n,
 				u32 flags)
 {
+	struct tc_u_hnode *ht = rtnl_dereference(n->ht_down);
 	struct tcf_block *block = tp->chain->block;
 	struct tc_cls_u32_offload cls_u32 = {};
 	bool skip_sw = tc_skip_sw(flags);

@@ -563,7 +564,7 @@ static int u32_replace_hw_knode(struct t
 	cls_u32.knode.sel = &n->sel;
 	cls_u32.knode.exts = &n->exts;
 	if (n->ht_down)
-		cls_u32.knode.link_handle = n->ht_down->handle;
+		cls_u32.knode.link_handle = ht->handle;
 
 	err = tc_setup_cb_call(block, NULL, TC_SETUP_CLSU32, &cls_u32, skip_sw);
 	if (err < 0) {

@@ -840,8 +841,9 @@ static void u32_replace_knode(struct tcf
 static struct tc_u_knode *u32_init_knode(struct tcf_proto *tp,
 					 struct tc_u_knode *n)
 {
-	struct tc_u_knode *new;
+	struct tc_u_hnode *ht = rtnl_dereference(n->ht_down);
 	struct tc_u32_sel *s = &n->sel;
+	struct tc_u_knode *new;
 
 	new = kzalloc(sizeof(*n) + s->nkeys*sizeof(struct tc_u32_key),
 		      GFP_KERNEL);

@@ -859,11 +861,11 @@ static struct tc_u_knode *u32_init_knode
 	new->fshift = n->fshift;
 	new->res = n->res;
 	new->flags = n->flags;
-	RCU_INIT_POINTER(new->ht_down, n->ht_down);
+	RCU_INIT_POINTER(new->ht_down, ht);
 
 	/* bump reference count as long as we hold pointer to structure */
-	if (new->ht_down)
-		new->ht_down->refcnt++;
+	if (ht)
+		ht->refcnt++;
 
 #ifdef CONFIG_CLS_U32_PERF
 	/* Statistics may be incremented by readers during update

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/net_sched-get-rid-of-rcu_barrier-in-tcf_block_put_ext.patch queue-4.15/ipv6-change-route-cache-aging-logic.patch queue-4.15/cls_u32-add-missing-rcu-annotation.patch