diff options
author | Breno Leitao <leitao@debian.org> | 2024-12-02 16:22:05 -0800 |
---|---|---|
committer | Jakub Kicinski <kuba@kernel.org> | 2024-12-04 18:41:37 -0800 |
commit | a9ab02ed97c654a9ea09afb3e6294cea3768c388 (patch) | |
tree | 33e3a623ee029eb2eb5db74cdda20db004c65d84 | |
parent | bb18265c3aba92b91a1355609769f3e967b65dee (diff) |
netpoll: Use rtnl_dereference() for npinfo pointer access
In the __netpoll_setup() function, when accessing the device's npinfo
pointer, replace rcu_access_pointer() with rtnl_dereference(). This
change is more appropriate, as suggested by Herbert Xu[1].
The function is called with the RTNL mutex held, and the pointer is
being dereferenced later, so, dereference earlier and just reuse the
pointer for the if/else.
The replacement ensures correct pointer access while maintaining
the existing locking and RCU semantics of the netpoll subsystem.
Link: https://lore.kernel.org/lkml/Zz1cKZYt1e7elibV@gondor.apana.org.au/ [1]
Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Link: https://patch.msgid.link/20241202-netpoll_rcu_herbet_fix-v2-1-2b9d58edc76a@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
-rw-r--r-- | net/core/netpoll.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 2e459b9d88eb..99e5aa9cc992 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -634,7 +634,8 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) goto out; } - if (!rcu_access_pointer(ndev->npinfo)) { + npinfo = rtnl_dereference(ndev->npinfo); + if (!npinfo) { npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL); if (!npinfo) { err = -ENOMEM; @@ -654,7 +655,6 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) goto free_npinfo; } } else { - npinfo = rtnl_dereference(ndev->npinfo); refcount_inc(&npinfo->refcnt); } |