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[95.21.2.212]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-499be3a3e2esm10640175e9.1.2026.08.21.07.48.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 21 Aug 2026 07:49:00 -0700 (PDT) Message-ID: <3b85e6e2-29d0-43ea-abe2-246f1148939a@gmail.com> Date: Fri, 21 Aug 2026 16:48:58 +0200 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 v4] Memory leak error in qxl unbind To: Greg KH Cc: Christian Koenig , Huang Rui , Matthew Auld , Matthew Brost , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-kernel-mentees@lists.linux.dev, stable@vger.kernel.org References: <20260809165326.164763-1-megia.oscar@gmail.com> <2026080941-edge-lurk-2146@gregkh> Content-Language: en-US, es-ES From: =?UTF-8?Q?Oscar_Megia_L=C3=B3pez?= In-Reply-To: <2026080941-edge-lurk-2146@gregkh> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 8/9/26 20:19, Greg KH wrote: > On Sun, Aug 09, 2026 at 06:53:14PM +0200, Óscar Megía López wrote: >> I discovered an OOM after run the script below >> (I updated it and added a sleep to allow enough time for the cache to >> recover): >> >> while [ 1 -eq 1 ]; do\ >> i=$((i+1)); echo 0000:00:01.0 > /sys/bus/pci/drivers/qxl/unbind;\ >> if (($i%1000==0)); then\ >> echo i=$i; free;\ >> grep nr_free_pages /proc/vmstat;\ >> grep -E "PageTables|VmallocUsed|Slab|Reclaimable" /proc/meminfo;\ >> sync; echo 3 > /proc/sys/vm/drop_caches;\ >> echo 1 > /proc/sys/vm/compact_memory;\ >> sleep 10s;\ >> free;\ >> grep nr_free_pages /proc/vmstat;\ >> grep -E "PageTables|VmallocUsed|Slab|Reclaimable" /proc/meminfo;\ >> uptime;\ >> fi;\ >> echo 0000:00:01.0 > /sys/bus/pci/drivers/qxl/bind;\ >> done >> >> The OOM isn't just a simple leak; it's a refcount corruption which renders >> the list_lru fix dead code after the first mid-init failure. >> >> Here's the chain: >> >> Bug 1: ttm_pool_type_init() does not check return from list_lru_init(). >> >> Fix: Check the return value from list_lru_init() and propagate the error. >> >> Bug 2: ttm_pool_fini() does not destroy list lru with list_lru_destroy(). >> >> Fix: Add list_lru_destroy() after ttm_pool_type_fini(). >> >> Bug 3: ttm_pool_mgr_init() does not check ttm_pool_type_init() return >> and does not free pool if returns error. >> >> Fix: Move up shrinker_alloc(), check ttm_pool_type_init() return and free >> pool types and shrinker if non-zero and return error. >> >> Bug 4: ttm_pool_mgr_fini() does not destroy the list_lru. >> >> Fix: Add list_lru_destroy() after ttm_pool_type_fini(). >> >> Fixed check for an empty shrinker_list. > Why is this not 4 different patches as part of a series? > >> This patch depends on patch ("[PATCH v3] drm/qxl: fix use-after-free in >> qxl_irq_handler on PCI"), link [1] below. > That's not going to age well in a changelog text :( I'm a newbie. What's the best way to add a patch it depends on? > > thanks, > > greg k-h