diff options
| author |   Florian Westphal <fw@strlen.de> | 2017-08-10 16:53:00 +0200 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2017-08-10 09:50:22 -0700 |
| commit | d38a65125f93b2fbd17cd37ccc5ec0f0b799cc55 (patch) | |
| tree | a9279b0bb53877dbf1ec2527d79a54311b58ccf8 /net/core | |
| parent | rtnetlink: switch rtnl_link_get_slave_info_data_size to rcu (diff) | |
| download | linux-dev-d38a65125f93b2fbd17cd37ccc5ec0f0b799cc55.tar.xz linux-dev-d38a65125f93b2fbd17cd37ccc5ec0f0b799cc55.zip | |
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')
| -rw-r--r-- | net/core/rtnetlink.c | 7 |
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"); |