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	id 1rkvpT-0002LQ-On; Fri, 15 Mar 2024 01:53:47 +0100
Date: Fri, 15 Mar 2024 01:53:47 +0100
From: Florian Westphal <fw@strlen.de>
To: Chenyuan Yang <chenyuan0y@gmail.com>
Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
	pabeni@redhat.com, horms@kernel.org, anjali.k.kulkarni@oracle.com,
	pctammela@mojatatu.com, andriy.shevchenko@linux.intel.com,
	dhowells@redhat.com, kuniyu@amazon.com, netdev@vger.kernel.org,
	zzjas98@gmail.com
Subject: Re: [net/netlink] Question about potential memleak in
 netlink_proto_init()
Message-ID: <20240315005347.GA8896@breakpoint.cc>
References: <ZfOalln/myRNOkH6@cy-server>
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User-Agent: Mutt/1.10.1 (2018-07-13)

Chenyuan Yang <chenyuan0y@gmail.com> wrote:
> Dear Netlink Developers,
> 
> We are curious whether the function `netlink_proto_init()` might have a memory leak.

Yes, but

> The function is https://elixir.bootlin.com/linux/v6.8/source/net/netlink/af_netlink.c#L2908
> and the relevant code is
> ```
> static int __init netlink_proto_init(void)
> {
> 	int i;
>   ...
> 
> 	for (i = 0; i < MAX_LINKS; i++) {
> 		if (rhashtable_init(&nl_table[i].hash,
> 				    &netlink_rhashtable_params) < 0) {
> 			while (--i > 0)
> 				rhashtable_destroy(&nl_table[i].hash);
> 			kfree(nl_table);
> 			goto panic;

... this calls panic(), kernel will crash intentionally.

Perhaps best patch would be to remove this error handling
and panic straight away, this is pretty much dead code.