batadv_show_throughput_override() invokes batadv_hardif_get_by_netdev(), which gets a batadv_hard_iface object from net_dev with increased refcnt and its reference is assigned to a local pointer 'hard_iface'.
When batadv_show_throughput_override() returns, "hard_iface" becomes invalid, so the refcount should be decreased to keep refcount balanced.
The issue happens in the normal path of batadv_show_throughput_override(), which forgets to decrease the refcnt increased by batadv_hardif_get_by_netdev() before the function returns, causing a refcnt leak.
Fix this issue by calling batadv_hardif_put() before the batadv_show_throughput_override() returns in the normal path.
Signed-off-by: Xiyu Yang xiyuyang19@fudan.edu.cn Signed-off-by: Xin Tan tanxin.ctf@gmail.com --- net/batman-adv/sysfs.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/net/batman-adv/sysfs.c b/net/batman-adv/sysfs.c index 97736696d042..0f962dcd239e 100644 --- a/net/batman-adv/sysfs.c +++ b/net/batman-adv/sysfs.c @@ -1190,6 +1190,7 @@ static ssize_t batadv_show_throughput_override(struct kobject *kobj,
tp_override = atomic_read(&hard_iface->bat_v.throughput_override);
+ batadv_hardif_put(hard_iface); return sprintf(buff, "%u.%u MBit\n", tp_override / 10, tp_override % 10); }
On Wednesday, 15 April 2020 10:31:50 CEST Xiyu Yang wrote: [...]
Fix this issue by calling batadv_hardif_put() before the
[...]
Thanks, fixes for batadv_store_throughput_override [1] and batadv_show_throughput_override [2] were applied. I've also added the missing Fixes: line to both patches.
May I ask whether you are still a user of the deprecated sysfs interface or did you find this in an automated fashion?
Thanks, Sven
[1] https://git.open-mesh.org/linux-merge.git/commit/cd339d8b14cd895d8333d94d832... [2] https://git.open-mesh.org/linux-merge.git/commit/3d3e548f74fe51aee9a3c9e2975...
On Wed, Apr 15, 2020 at 11:04:02AM +0200, Sven Eckelmann wrote:
On Wednesday, 15 April 2020 10:31:50 CEST Xiyu Yang wrote: [...]
Fix this issue by calling batadv_hardif_put() before the
[...]
Thanks, fixes for batadv_store_throughput_override [1] and batadv_show_throughput_override [2] were applied. I've also added the missing Fixes: line to both patches.
May I ask whether you are still a user of the deprecated sysfs interface or did you find this in an automated fashion?
Thanks, Sven
[1] https://git.open-mesh.org/linux-merge.git/commit/cd339d8b14cd895d8333d94d832... [2] https://git.open-mesh.org/linux-merge.git/commit/3d3e548f74fe51aee9a3c9e2975...
Thanks for your confirmation! We are looking for some automated ways to find this kind of bug.
b.a.t.m.a.n@lists.open-mesh.org