From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 10061EEBA for ; Sun, 11 Aug 2024 12:35:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723379723; cv=none; b=V9/xkqsiV1ATiBojlgmcr9RMYH5WhV1y8cXkIE0ceMJHGsxRJX9ICE78mfnNvwP2RkyPG92PtMkuMbdFCvX8/9jFUvTvaXW9S+/FX+xjGJIBgzu17W6cfzVpxwTDUhmcT+YvbqlmPMqlm4NFhsDzSxeYibjuzI/9vgYDuADeYKQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723379723; c=relaxed/simple; bh=8HbDmLL+NTBeeBc0mZ30qbLS+R+pE60UQRFzXh0Qd40=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=h9c9CUmRx3gMUCgpS0VEeBoyDy+39OFk4BQHIp7rSQWq3qpIaZsdpQJiZ/mT45UlekorDQra7JYMiriaDAKf2cLNj7Uh9srWg7Jh6oDODFx6sXSokQJQKprdDt527qkC44E43QUbAoQO6UtfWlOlXEFGXqv6kPSXpKzgwEMyH6Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=R5nCy06h; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="R5nCy06h" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1723379721; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=iHlXnDYMSxlvXOLG5yqCHeaThdF+GjL3IUfr75SJ08A=; b=R5nCy06h52ZpdzlZ6uSVKPhPudbBMQ2Q25JwpSNaKNFmsQ46eq8AFEbJw7LVv88f4GHmm2 Jv4QEKjzJ5K8AFyc5wDPplP4mf2r+xaJVaboRdfihy4wFGIldeD5k47S2U0TaVtg6+wDIq +HF++3i/r/ozQPiZOkEST112OEJ+S+g= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-357-H9lsxKNuPV-qWIxBFCY7Sg-1; Sun, 11 Aug 2024 08:35:16 -0400 X-MC-Unique: H9lsxKNuPV-qWIxBFCY7Sg-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4ABCF195609E; Sun, 11 Aug 2024 12:35:14 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.224.19]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 1F5A219560AE; Sun, 11 Aug 2024 12:35:07 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Sun, 11 Aug 2024 14:35:11 +0200 (CEST) Date: Sun, 11 Aug 2024 14:35:04 +0200 From: Oleg Nesterov To: syzbot , Andrii Nakryiko , jolsa@kernel.org Cc: acme@kernel.org, adrian.hunter@intel.com, alexander.shishkin@linux.intel.com, irogers@google.com, kan.liang@linux.intel.com, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-trace-kernel@vger.kernel.org, mark.rutland@arm.com, mhiramat@kernel.org, mingo@redhat.com, namhyung@kernel.org, peterz@infradead.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [perf?] KASAN: slab-use-after-free Read in __uprobe_unregister Message-ID: <20240811123504.GB30068@redhat.com> References: <000000000000382d39061f59f2dd@google.com> <20240811121444.GA30068@redhat.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240811121444.GA30068@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 On 08/11, Oleg Nesterov wrote: > > Hmm, bpf_uprobe_multi_link_attach() looks obviously wrong. > > bpf_link_prime() is called after the > > for (i = 0; i < cnt; i++) { > uprobe_register(...); > ... > } > > loop. If bpf_link_prime() fails, bpf_uprobe_multi_link_attach() just do > kvfree(uprobes) without _unregister(). In particular, this leaks the freed > bpf_uprobe->consumer in the uprobe->consumers list. > > After that another _unregister() on the same uprobe can hit the problem. > > I guess we need a simple patch for -stable... Something like below on top of perf/core. But I don't like the usage of "i" in the +error_unregister path... Oleg. --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -3486,17 +3486,19 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr &uprobes[i].consumer); if (IS_ERR(uprobes[i].uprobe)) { err = PTR_ERR(uprobes[i].uprobe); - bpf_uprobe_unregister(uprobes, i); - goto error_free; + goto error_unregister; } } err = bpf_link_prime(&link->link, &link_primer); if (err) - goto error_free; + goto error_unregister; return bpf_link_settle(&link_primer); +error_unregister: + bpf_uprobe_unregister(uprobes, i); + error_free: kvfree(uprobes); kfree(link);