From 40b1c813ba8e0aac9ee36b57f2835777506084c6 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Sun, 25 Nov 2018 16:08:51 +0000 Subject: [PATCH] net: bridge: remove redundant checks for null p->dev and p->br A recent change added a null check on p->dev after p->dev was being dereferenced by the ns_capable check on p->dev. It turns out that neither the p->dev and p->br null checks are necessary, and can be removed, which cleans up a static analyis warning. As Nikolay Aleksandrov noted, these checks can be removed because: "My reasoning of why it shouldn't be possible: - On port add new_nbp() sets both p->dev and p->br before creating kobj/sysfs - On port del (trickier) del_nbp() calls kobject_del() before call_rcu() to destroy the port which in turn calls sysfs_remove_dir() which uses kernfs_remove() which deactivates (shouldn't be able to open new files) and calls kernfs_drain() to drain current open/mmaped files in the respective dir before continuing, thus making it impossible to open a bridge port sysfs file with p->dev and p->br equal to NULL. So I think it's safe to remove those checks altogether. It'd be nice to get a second look over my reasoning as I might be missing something in sysfs/kernfs call path." Thanks to Nikolay Aleksandrov's suggestion to remove the check and David Miller for sanity checking this. Detected by CoverityScan, CID#751490 ("Dereference before null check") Fixes: a5f3ea54f3cc ("net: bridge: add support for raw sysfs port options") Signed-off-by: Colin Ian King Acked-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- net/bridge/br_sysfs_if.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c index 7c87a2fe5248..88715edb119a 100644 --- a/net/bridge/br_sysfs_if.c +++ b/net/bridge/br_sysfs_if.c @@ -320,9 +320,6 @@ static ssize_t brport_store(struct kobject *kobj, if (!rtnl_trylock()) return restart_syscall(); - if (!p->dev || !p->br) - goto out_unlock; - if (brport_attr->store_raw) { char *buf_copy;