Re: [PATCH] ipv4: fib: Fix fib_info_hash_alloc() allocation type

[Kuniyuki Iwashima <kuniyu@amazon.com>]

Thanks for CC me, David.

From: David Ahern <dsahern@kernel.org>
Date: Mon, 28 Apr 2025 16:50:53 -0600
> On 4/25/25 11:05 PM, Kees Cook wrote:
> > In preparation for making the kmalloc family of allocators type aware,
> > we need to make sure that the returned type from the allocation matches
> > the type of the variable being assigned. (Before, the allocator would
> > always return "void *", which can be implicitly cast to any pointer type.)
> > 
> > This was allocating many sizeof(struct hlist_head *) when it actually
> > wanted sizeof(struct hlist_head). Luckily these are the same size.
> > Adjust the allocation type to match the assignment.
> > 
> > Signed-off-by: Kees Cook <kees@kernel.org>
> > ---
> > Cc: "David S. Miller" <davem@davemloft.net>
> > Cc: David Ahern <dsahern@kernel.org>
> > Cc: Eric Dumazet <edumazet@google.com>
> > Cc: Jakub Kicinski <kuba@kernel.org>
> > Cc: Paolo Abeni <pabeni@redhat.com>
> > Cc: Simon Horman <horms@kernel.org>
> > Cc: <netdev@vger.kernel.org>
> > ---
> >  net/ipv4/fib_semantics.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
> > index f68bb9e34c34..37d12b0bc6be 100644
> > --- a/net/ipv4/fib_semantics.c
> > +++ b/net/ipv4/fib_semantics.c
> > @@ -365,7 +365,7 @@ static struct hlist_head *fib_info_laddrhash_bucket(const struct net *net,
> >  static struct hlist_head *fib_info_hash_alloc(unsigned int hash_bits)
> >  {
> >  	/* The second half is used for prefsrc */
> > -	return kvcalloc((1 << hash_bits) * 2, sizeof(struct hlist_head *),
> > +	return kvcalloc((1 << hash_bits) * 2, sizeof(struct hlist_head),
> >  			GFP_KERNEL);
> >  }
> >  
> 
> Reviewed-by: David Ahern <dsahern@kernel.org>
> 
> Fixes: fa336adc100e ("ipv4: fib: Allocate fib_info_hash[] and
> fib_info_laddrhash[] by kvcalloc().)

I agree this should target net.git as the last statement
will be false with LOCKDEP.

Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>

Thanks!