From: Arnd Bergmann <[email protected]>
Upstream commit:
commit 260637903f47f20c5918bb5c1eea52b2a28ea863
Author: Arnd Bergmann <[email protected]>
Date: Mon Jul 22 17:00:01 2019 +0200
ovs: datapath: hide clang frame-overflow warnings
Some functions in the datapath code are factored out so that each
one has a stack frame smaller than 1024 bytes with gcc. However,
when compiling with clang, the functions are inlined more aggressively
and combined again so we get
net/openvswitch/datapath.c:1124:12: error: stack frame size of 1528 bytes
in function 'ovs_flow_cmd_set' [-Werror,-Wframe-larger-than=]
Marking both get_flow_actions() and ovs_nla_init_match_and_action()
as 'noinline_for_stack' gives us the same behavior that we see with
gcc, and no warning. Note that this does not mean we actually use
less stack, as the functions call each other, and we still get
three copies of the large 'struct sw_flow_key' type on the stack.
The comment tells us that this was previously considered safe,
presumably since the netlink parsing functions are called with
a known backchain that does not also use a lot of stack space.
Fixes: 9cc9a5cb176c ("datapath: Avoid using stack larger than 1024.")
Signed-off-by: Arnd Bergmann <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Signed-off-by: Greg Rose <[email protected]>
---
datapath/datapath.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/datapath/datapath.c b/datapath/datapath.c
index 94e4f6f..15af156 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -1069,7 +1069,7 @@ error:
}
/* Factor out action copy to avoid "Wframe-larger-than=1024" warning. */
-static struct sw_flow_actions *get_flow_actions(struct net *net,
+static noinline_for_stack struct sw_flow_actions *get_flow_actions(struct net
*net,
const struct nlattr *a,
const struct sw_flow_key *key,
const struct sw_flow_mask *mask,
@@ -1103,12 +1103,13 @@ static struct sw_flow_actions *get_flow_actions(struct
net *net,
* we should not to return match object with dangling reference
* to mask.
* */
-static int ovs_nla_init_match_and_action(struct net *net,
- struct sw_flow_match *match,
- struct sw_flow_key *key,
- struct nlattr **a,
- struct sw_flow_actions **acts,
- bool log)
+static noinline_for_stack int
+ovs_nla_init_match_and_action(struct net *net,
+ struct sw_flow_match *match,
+ struct sw_flow_key *key,
+ struct nlattr **a,
+ struct sw_flow_actions **acts,
+ bool log)
{
struct sw_flow_mask mask;
int error = 0;
--
1.8.3.1
_______________________________________________
dev mailing list
[email protected]
https://mail.openvswitch.org/mailman/listinfo/ovs-dev
