From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793831452; b=ZqKravhnOAWsYX2D75QnDnfEpo5IqbmG9fiTZOPRDkzfWtXv+ZBvWNHFR2DjSE5kE4We 7cgaVg4MhLD5B2Ee7ZxUledfuu3G8lSnLWQsZDrdRSPJcMnAwMALheoW0ccrKise5yrrG HvAN2+V1vLbIskfilG4KlmN5UkceaVXEBEyLyQY858ty2D2ouLI7U5iiZM4o8VB21gbhB vDkdLRj9f2RpPYgAQUAfFnK8oytwZc7ZjXEwFzNN+R2D1pbtEViiaELlOQ9k+BIbt+jZ4 TrESLo4JyYnFGFLoC1VYwNJpl9KxUlb2sv6xj6Wv4rWY6O02PSRAEQpZjnyFuu5gnaQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793831452; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=uuBLJdtzuRcJngeSrlWUsIz5hyhxCxOl5bgpgATbaxQ=; b=XOREmEdpsxQVXkmjRzGs53N93MEkItPyaHpnTd9XZ3AhW678Ip+KwvaTCfluEDN+GsdG EJf71qtOdR1J9ip0jpQ7A8AWvUaOnkUGv1pysYcoL+daQLPoJ7+ptSnJyjBn7yGqAKfmi 9X78LfgR4SoxoYRplXcDazPTUfiisKd4KUgXgAnll4tx7R9ice9PpGdh3Tg46mjKAh2XE 6oz320b1xvqTiL2422aIyAirBQ87z2w1lgVnmbCARJohMnnJ87UgFQxu3mvnslJthWEu6 Qc2CD2CKPzrUhhAyKpW7daNFIj6TSsrHIdkdalzH1y1how9RTUs5qtw1iWdUYl3Y7DQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=koGQEv7Y; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 83084606A328; Wed, 4 Nov 2026 22:30:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=koGQEv7Y Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C0691F000C1; Wed, 4 Nov 2026 22:30:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793831452; bh=uuBLJdtzuRcJngeSrlWUsIz5hyhxCxOl5bgpgATbaxQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=koGQEv7YD3VaWJwaAyL45sPIW2CkBy7liss0Wmvy21zqJOoF1Hr5nJx8Hy3FuwINO Pjf7P3jBRnIPVnQcrbfS5+qrI2TBwSfEEaz0j4KwSGy7tdmNaUtoWgH7DZtpA3OuIB xJdCDLG/YVDPvHqeGlWyTCjYSLSi6Ajr8V1lkZ/8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Boris Brezillon , Liviu Dudau , Osama Abdelkader , Steven Price Subject: [PATCH 6.18 0710/1005] drm/panthor: Fix TOCTOU race between GROUP_REGISTERED check and erase Date: Wed, 4 Nov 2026 16:07:23 -0500 Message-ID: <20261104211103.450324721@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Osama Abdelkader commit 7764289d76a38c3a2f9b093bf17e193ab54acd70 upstream. panthor_group_destroy() checks the GROUP_REGISTERED mark and then calls xa_erase() without holding the xarray lock across both. If the handle is destroyed by another thread in between, and a concurrent GROUP_CREATE reuses the freed ID, the first destroy erases and releases the new, still-initializing group, leading to a use-after-free in panthor_group_create(). Do the mark check and erase atomically under xa_lock(). Fixes: eec7e23d848d ("drm/panthor: Prevent potential UAF in group creation") Assisted-by: Claude:claude-opus-5.5 Reviewed-by: Boris Brezillon Reviewed-by: Liviu Dudau Cc: stable@vger.kernel.org Signed-off-by: Osama Abdelkader Reviewed-by: Steven Price Signed-off-by: Liviu Dudau Link: https://patch.msgid.link/20261008100935.3059587-1-osama.abdelkader@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/panthor/panthor_sched.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) --- a/drivers/gpu/drm/panthor/panthor_sched.c +++ b/drivers/gpu/drm/panthor/panthor_sched.c @@ -3664,12 +3664,18 @@ int panthor_group_destroy(struct panthor struct panthor_group_pool *gpool = pfile->groups; struct panthor_device *ptdev = pfile->ptdev; struct panthor_scheduler *sched = ptdev->scheduler; - struct panthor_group *group; + struct panthor_group *group = NULL; - if (!xa_get_mark(&gpool->xa, group_handle, GROUP_REGISTERED)) - return -EINVAL; + /* + * Check the mark and erase the entry atomically, so a concurrent + * destroy + create can't make us erase a group that's still being + * initialized and happens to reuse the same handle. + */ + xa_lock(&gpool->xa); + if (xa_get_mark(&gpool->xa, group_handle, GROUP_REGISTERED)) + group = __xa_erase(&gpool->xa, group_handle); + xa_unlock(&gpool->xa); - group = xa_erase(&gpool->xa, group_handle); if (!group) return -EINVAL;