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authorFlorian Westphal <fw@strlen.de>2017-08-10 16:53:00 +0200
committerDavid S. Miller <davem@davemloft.net>2017-08-10 09:50:22 -0700
commitd38a65125f93b2fbd17cd37ccc5ec0f0b799cc55 (patch)
treea9279b0bb53877dbf1ec2527d79a54311b58ccf8 /net/core/rtnetlink.c
parent8515ae38435895ba2862840d3e82140fc0a77554 (diff)
rtnetlink: init handler refcounts to 1
If using CONFIG_REFCOUNT_FULL=y we get following splat: refcount_t: increment on 0; use-after-free. WARNING: CPU: 0 PID: 304 at lib/refcount.c:152 refcount_inc+0x47/0x50 Call Trace: rtnetlink_rcv_msg+0x191/0x260 ... This warning is harmless (0 is "no callback running", not "memory was freed"). Use '1' as the new 'no handler is running' base instead of 0 to avoid this. Fixes: 019a316992ee ("rtnetlink: add reference counting to prevent module unload while dump is in progress") Reported-by: Sabrina Dubroca <sdubroca@redhat.com> Reported-by: kernel test robot <fengguang.wu@intel.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/rtnetlink.c')
-rw-r--r--net/core/rtnetlink.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 087f2434813a..59eda6952bc9 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -262,7 +262,7 @@ void rtnl_unregister_all(int protocol)
synchronize_net();
- while (refcount_read(&rtnl_msg_handlers_ref[protocol]) > 0)
+ while (refcount_read(&rtnl_msg_handlers_ref[protocol]) > 1)
schedule();
kfree(handlers);
}
@@ -4324,6 +4324,11 @@ static struct pernet_operations rtnetlink_net_ops = {
void __init rtnetlink_init(void)
{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(rtnl_msg_handlers_ref); i++)
+ refcount_set(&rtnl_msg_handlers_ref[i], 1);
+
if (register_pernet_subsys(&rtnetlink_net_ops))
panic("rtnetlink_init: cannot initialize rtnetlink\n");