Re: [PATCH net v3] net: core: failover: fix NULL pointer dereference in failover_slave_register()
From: Jakub Kicinski <kuba@kernel.org>
Date: 2026-02-28 01:36:51
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kernel-janitors, lkml
On Thu, 26 Feb 2026 13:56:01 +0500 Zeeshan Ahmad wrote:
Smatch warns that 'fops' is dereferenced without a NULL check.
While other callbacks in this function properly check 'fops', the
rx_handler registration does not.
Consolidate the NULL check for 'fops' at the beginning of the function,
before it is first used in slave_pre_register(). This ensures 'fops' is
valid for the entire function scope and allows the removal of redundant
NULL checks later in the function, as suggested by Dan Carpenter.
Fixes: 30c8bd5aa8b2 ("net: Introduce generic failover module")Not really a fix, there's only one user - net_failover and it always passes the ops and has all callbacks.
quoted hunk ↗ jump to hunk
diff --git a/net/core/failover.c b/net/core/failover.c index 2a140b3ea669..47e4a91dcaa6 100644 --- a/net/core/failover.c +++ b/net/core/failover.c@@ -59,7 +59,10 @@ static int failover_slave_register(struct net_device *slave_dev) if (!failover_dev) goto done; - if (fops && fops->slave_pre_register && + if (WARN_ON_ONCE(!fops)) + goto done;
Better still please add this check in failover_register() so that we don't allow any device to be registered without ops. Then you can delete all the fops checks throughout this file, not just in this one function. -- pw-bot: cr