From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793025722; b=fZAN8VH5MZf4MnC+qKlbW4QAJRDOxGheRdXaBQNsnZaqU8P4hNtOeyYeshg4+Vkv1i1n wd2ZhKPjMJsUvN4TKaRGsCjRQBRR7nUux/xdt9VRt0Z6e34KmK4uYbFcg1meATZSW26vD QcoD56cyLJhMQAr/8mIzt5gvA+GD3YY3OaEkPQtsCg8Pssq14CuZ40LmjyfBfNPcQWGMz TYj9pWZn7ruQYVMK+vc2ry7uiauA3mJVWGsWgjv6TEX7IPwH9zFy53CdWujzvlFxKjGfy b5U2rUapzVOEIn+drq+K78p18oJ9jas1EqdRrYjpO7JtWuXXB7Vxj46vm+FwvjgITBQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793025722; h=DMARC-Filter:Received:Received:DKIM-Signature:Message-ID:Date: MIME-Version:User-Agent:Subject:To:Cc:References:Content-Language: From:In-Reply-To:Content-Type:Content-Transfer-Encoding; bh=Ez65BpebUQ+LzZHerBti0ml+PzvEp3wP1I1rTS2yZ9k=; b=WgcU2OGBSiVdYCvGJuuMngP6g/165etCT3T6PiSd5j7wi6xg5wFp1Kdw9ypjFyuYafa+ 05oOKZQ2GM2XOYkEUQVIXi8svZ3VzGyK7wQeG/pInCt0yWen7F2ZR+keGndXXQ9fL1PSh rEJM+3jLk9GFoT9hfRUc7hhgCHRDTqTRwmaB1HNNdBmal394polaw/k+N8LAeWg2hskwL YVsiKHaaDGP4YrdBs7MBv40KBdnL0p7ZVmP/tUTv7lflGGgC1sVbdW714xnf+H/CBbg3q wzo5OOWXJMoV2Path0M2JqhHkb+f3IHcE3mRbBbWJanLijgA9a0wR598aOwnviUKfHw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=V1BVr1N3; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D163E606A31A for ; Mon, 26 Oct 2026 14:42:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org D163E606A31A Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=V1BVr1N3 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0F5E615A1; Mon, 26 Oct 2026 07:41:58 -0700 (PDT) Received: from [10.2.212.8] (e134344.arm.com [10.2.212.8]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4BAA03F7B4; Mon, 26 Oct 2026 07:42:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1793025721; bh=devpMkqlvzmfIsTiMV2MoQfbNpvgTmDNNsOb8HPINhY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=V1BVr1N3Qqxj7gcY/ep6aR1lXjSC7poy8s9CxzmUwsk1SjBmQX0Ky04+PUyPEByk8 +PGlLvVN20cEtCr3WloEoUl3QRZlw2kAuoO/9yVgdyTC7Bdv/A1b5Edx41vSa+LP0S Okr9YUu6b/GuMkKuj7SHEbiMGCwRpcHn5xkP/bdM= Message-ID: Date: Mon, 26 Oct 2026 14:41:58 +0000 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] arm_mpam: return allocation errors as error pointers To: Sang-Hoon Choi , James Morse Cc: Reinette Chatre , Fenghua Yu , linux-kernel@vger.kernel.org, Changyul Lee References: <179075213853.3.16001626385793291460.idr-bug-33@gmail.com> Content-Language: en-US From: Ben Horgan In-Reply-To: <179075213853.3.16001626385793291460.idr-bug-33@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Sang-Hoon, On 30/09/2026 08:08, Sang-Hoon Choi wrote: > resctrl_arch_mon_ctx_alloc() stores the result of monitor allocation in > an allocated int. If monitor allocation fails, it still returns that pointer. > Callers check IS_ERR(), so they treat the failed allocation as a valid > monitor context and pass the error value on as a monitor index. > > For example, if the wait for a free monitor ends because a signal is > pending, the stored result is still -ENOSPC. Other allocation errors > also reach the same return path. > > Free the temporary allocation and return ERR_PTR(err) for negative > results. Leave successful indices and USE_PRE_ALLOCATED unchanged. > > Fixes: 2a3c79c61539 ("arm_mpam: resctrl: Allow resctrl to allocate monitors") > Reported-by: Changyul Lee > Link: https://github.com/lcy8047/radix-tree-bug-temp/blob/main/bug_list/idr-ida-xarray/wrong-id-value/IDR-BUG-33-mpam-monitor-id.md > Assisted-by: Sang-Hoon Choi > Signed-off-by: Sang-Hoon Choi > --- > Compile-tested on arm64 with allmodconfig and W=1 against mainline > 6f8319e3e9a44dd537d17f41565a8453c560a581. No hardware runtime test was > performed. > > drivers/resctrl/mpam_resctrl.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c > index 9d223057953a..945be7465ad3 100644 > --- a/drivers/resctrl/mpam_resctrl.c > +++ b/drivers/resctrl/mpam_resctrl.c > @@ -413,6 +413,13 @@ void *resctrl_arch_mon_ctx_alloc(struct rdt_resource *r, > } while (*ret == -ENOSPC && !signal_pending(current)); > finish_wait(&resctrl_mon_ctx_waiters, &wait); > > + if (*ret < 0) { > + int err = *ret; > + > + kfree(ret); > + return ERR_PTR(err); > + } > + > return ret; This seems like a good place to use the cleanup.h helpers, __free(kfree) and then pass on the pointer with return_ptr(ret). Thanks, Ben > } >