linux-kernel - Re: [PATCH 2/8] uprobes: revamp uprobe refcounting and lifetime management

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240805134418.GA11049@redhat.com>
Date: Mon, 5 Aug 2024 15:44:18 +0200
From: Oleg Nesterov <oleg@...hat.com>
To: Andrii Nakryiko <andrii@...nel.org>
Cc: linux-trace-kernel@...r.kernel.org, peterz@...radead.org,
	rostedt@...dmis.org, mhiramat@...nel.org, bpf@...r.kernel.org,
	linux-kernel@...r.kernel.org, jolsa@...nel.org, paulmck@...nel.org
Subject: Re: [PATCH 2/8] uprobes: revamp uprobe refcounting and lifetime
 management

On 07/31, Andrii Nakryiko wrote:
>
> @@ -732,11 +776,13 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset,
>  	uprobe->ref_ctr_offset = ref_ctr_offset;
>  	init_rwsem(&uprobe->register_rwsem);
>  	init_rwsem(&uprobe->consumer_rwsem);
> +	RB_CLEAR_NODE(&uprobe->rb_node);

I guess RB_CLEAR_NODE() is not necessary?

> @@ -1286,15 +1296,19 @@ static void build_probe_list(struct inode *inode,
>  			u = rb_entry(t, struct uprobe, rb_node);
>  			if (u->inode != inode || u->offset < min)
>  				break;
> +			u = try_get_uprobe(u);
> +			if (!u) /* uprobe already went away, safe to ignore */
> +				continue;
>  			list_add(&u->pending_list, head);

cosmetic nit, feel to ignore, but to me

			if (try_get_uprobe(u))
				list_add(&u->pending_list, head);

looks more readable.

Other than the lack of kfree() in put_uprobe() and WARN() in _unregister()
the patch looks good to me.

Oleg.