From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (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 983B42E62B6 for ; Fri, 4 Apr 2025 12:58:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743771504; cv=pass; b=eEpSbNPrzCcfthHpqisuIlyUvqyvhjaTkglurm2wCsB7/B2xo8lEqhdyLLquztC1tt5cYql5FgB6zVPTImxHrmM4QB6I9g55aduOt0L+OLiijAn+dfHfHV4CfdW14n03sPaLqwBc71I64cjd4QwO00E/cqrPx54VsstTE1n8WiY= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743771504; c=relaxed/simple; bh=1NUkmn93zltYrATavReLxL8vomELaK3wbCqJJBUtmVE=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=UyAOh+miCgLiuhk8TV3FwkBU1n3XHsSU7uq0pDoZ3CUJKnCL+ORAGBXfW+NycDJW6WSDhsZ1/gLIN7okEYCTPNh697/1sd2Zzi3mGRYoakU2OYlTDQ3/6+1RTuH3tRybUU/pRs8aj+7CbBRyUCZplITWKRt+Tv9eaGVCbXtzYnU= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=dmitry.osipenko@collabora.com header.b=Aez8+8Xz; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=dmitry.osipenko@collabora.com header.b="Aez8+8Xz" ARC-Seal: i=1; a=rsa-sha256; t=1743771473; cv=none; d=zohomail.com; s=zohoarc; b=hEnfFmxvzdFtRTSIwelHkDDiIIwvmp8Z4eKlZmICISdRMJX7v+fzFk8QxMPKg8uBX9yZwEfSGys0h1Eb3xfvkMykCD/++APNnERrA4fDRusjHJUZEhEZEvw2atfXjjy060oObjE6LdUvbuSSOxN/iosEZtj5RDXkgpNbaYtKc6U= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1743771473; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=eACs556LWYn/VXJSp36c3evelj61tsdIYGmy50dFBBo=; b=kyF34fNHuTazzDNS8kvCRvhSx6EdtH6yZO6htz8OmU7P0tmx2gynHSQh+6rdBvb9/lLo79NaSMDab3XDrVqEYGy24dikUTYHawDcYbyniIan0jcbTMloyCLOjZW0L/a8gou1lO8yEmk/GCM1Q7D52rTG+V6bjTZn2pl2G2aS5j8= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=dmitry.osipenko@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1743771473; s=zohomail; d=collabora.com; i=dmitry.osipenko@collabora.com; h=Message-ID:Date:Date:MIME-Version:Subject:Subject:From:From:To:To:Cc:Cc:References:In-Reply-To:Content-Type:Content-Transfer-Encoding:Message-Id:Reply-To; bh=eACs556LWYn/VXJSp36c3evelj61tsdIYGmy50dFBBo=; b=Aez8+8XzBP6r/zqefw8kNqUqTy6KdxYrq0MNqyxj35+nbobgFrSbryqT8Ag/hJ1p UOvBJjMeHrqgq//mVJlbFF4vyIaT2k1C6CO1K1e5X47v/3+kJO6cyfZYqrJHTFVnOln ZEwdYQtNq006hGJe8MBjo48GcGBSdMeEuvJXqabk= Received: by mx.zohomail.com with SMTPS id 1743771470818665.4330160938939; Fri, 4 Apr 2025 05:57:50 -0700 (PDT) Message-ID: Date: Fri, 4 Apr 2025 15:57:47 +0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1] drm/shmem-helper: Fix unsetting shmem vaddr while vmap refcount > 0 From: Dmitry Osipenko To: Thomas Zimmermann , Lucas De Marchi , Boris Brezillon Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel@collabora.com References: <20250403142633.484660-1-dmitry.osipenko@collabora.com> Content-Language: en-US In-Reply-To: <20250403142633.484660-1-dmitry.osipenko@collabora.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ZohoMailClient: External On 4/3/25 17:26, Dmitry Osipenko wrote: > We switched to use refcount_t for vmaps and missed to change the vunmap > code to properly unset the vmap pointer, which is now cleared while vmap's > refcount > 0. Clear the cached vmap pointer only when refcounting drops to > zero to fix the bug. > > Fixes: e1fc39a92332 ("drm/shmem-helper: Use refcount_t for vmap_use_count") > Reported-by: Lucas De Marchi > Closes: https://lore.kernel.org/dri-devel/20250403105053.788b0f6e@collabora.com/T/#m3dca6d81bedc8d6146a56b82694624fbc6fa4c96 > Signed-off-by: Dmitry Osipenko > --- > drivers/gpu/drm/drm_gem_shmem_helper.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > index 2d924d547a51..aa43265f4f4f 100644 > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > @@ -415,11 +415,11 @@ void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem, > > if (refcount_dec_and_test(&shmem->vmap_use_count)) { > vunmap(shmem->vaddr); > + shmem->vaddr = NULL; > + > drm_gem_shmem_unpin_locked(shmem); > } > } > - > - shmem->vaddr = NULL; > } > EXPORT_SYMBOL_GPL(drm_gem_shmem_vunmap_locked); > Applied to misc-next -- Best regards, Dmitry