From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-100.freemail.mail.aliyun.com (out30-100.freemail.mail.aliyun.com [115.124.30.100]) (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 D1F6D34DB72 for ; Sun, 20 Sep 2026 08:28:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.100 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789892927; cv=none; b=CiojfEJ87Dws/FOj4VZ+JVyxd4iV7FXNDC3CVs3ZB8lH//PEggz5wIYvtix9zVDnj9AD7i5b2BfmodUEU5RvsaO1v9SYd0UnNWuLLEx8orurbmmqtAWL+U6TU3TwhJDav65cFCuVE+VELz5K0Gq8yaNVme/LSouqv29pPg2twxI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789892927; c=relaxed/simple; bh=TWC6ZQPaZb0Cvk3H7O6j/aQMEgtQk2q2SNjR8jyYJeE=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=f9+xy0wc1/qxOsStHzu0fluqlnaS+gNvSNqa7k2pM7JtIJFKkFUNVtuhkys6v6EshvuxbnUIAU/8iGNMk29e684bI16DX8eDvaMwcGsHiHgNfl3RoE5knyCHYSBDDWp9wDGaQvwd8nhgNtvL8OLiKP1uHzRXMJ70ZoWSTsbJq6w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=MTzQ7/Um; arc=none smtp.client-ip=115.124.30.100 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="MTzQ7/Um" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1789892922; h=Message-ID:Date:MIME-Version:Subject:From:To:Content-Type; bh=H6PQ1Bn9SUjfUCfgHL+o5iRpfiaRAYs2eCR9et5btaE=; b=MTzQ7/UmgaJnPCZfRteKx3HSR1/vc9lBFcwwwl66M64CJv444IlU8vETbnQ4FkNif0ZCjxcaVLfurpyWaZICx9zLpg8c2PP91V4G66UcNs4VFWksVWbMM9fNGTDqakXjJTjGRIBdIyvCBDs7ojw8C3y3775DUDQnUSNdK9+dRMU= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R131e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam011083073210;MF=kanie@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0XBFVgaN_1789892920; Received: from 30.178.84.196(mailfrom:kanie@linux.alibaba.com fp:SMTPD_---0XBFVgaN_1789892920 cluster:ay36) by smtp.aliyun-inc.com; Sun, 20 Sep 2026 16:28:41 +0800 Message-ID: <19220f15-4215-4dc7-9ba7-64da0fceb864@linux.alibaba.com> Date: Sun, 20 Sep 2026 16:28:40 +0800 Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] dmaengine: idxd: Fix use-after-free of idxd_wq From: Guixin Liu To: Vinicius Costa Gomes , Dave Jiang , Vinod Koul , Frank Li Cc: dmaengine@vger.kernel.org, Xunlei Pang , oliver.yang@linux.alibaba.com References: <20260415095030.42183-1-kanie@linux.alibaba.com> In-Reply-To: <20260415095030.42183-1-kanie@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi idxd maintainers, could anyone merge this patch? Best Regards, Guixin Liu 在 2026/4/15 17:50, Guixin Liu 写道: > We found an idxd_wq use-after-free issue with kasan > when remove the idxd PCI device: > > BUG: KASAN: slab-use-after-free in idxd_device_drv_remove+0x1f8/0x240 [idxd] > Call Trace: > > dump_stack_lvl+0x32/0x50 > print_address_description.constprop.0+0x2c/0x390 > ? idxd_device_drv_remove+0x1f8/0x240 [idxd] > print_report+0xba/0x280 > ? kasan_addr_to_slab+0x9/0xa0 > ? idxd_device_drv_remove+0x1f8/0x240 [idxd] > kasan_report+0xab/0xe0 > ? idxd_device_drv_remove+0x1f8/0x240 [idxd] > idxd_device_drv_remove+0x1f8/0x240 [idxd] > device_release_driver_internal+0x391/0x560 > bus_remove_device+0x1f5/0x3f0 > device_del+0x392/0x990 > ? __pfx_device_del+0x10/0x10 > ? kobject_cleanup+0x117/0x360 > ? idxd_unregister_devices+0x229/0x320 [idxd] > device_unregister+0x13/0xa0 > idxd_remove+0x4f/0x1b0 [idxd] > pci_device_remove+0xa7/0x1d0 > device_release_driver_internal+0x391/0x560 > ? pci_pme_active+0x1e/0x450 > pci_stop_bus_device+0x10a/0x150 > pci_stop_and_remove_bus_device_locked+0x16/0x30 > remove_store+0xcf/0xe0 > > Freed by task 15535: > kasan_save_stack+0x1c/0x40 > kasan_set_track+0x21/0x30 > kasan_save_free_info+0x27/0x40 > ____kasan_slab_free+0x171/0x240 > slab_free_freelist_hook+0xde/0x190 > __kmem_cache_free+0x19e/0x310 > device_release+0x98/0x210 > kobject_cleanup+0x102/0x360 > idxd_unregister_devices+0xb3/0x320 [idxd] > dxd_remove+0x3f/0x1b0 [idxd] > pci_device_remove+0xa7/0x1d0 > device_release_driver_internal+0x391/0x560 > pci_stop_bus_device+0x10a/0x150 > pci_stop_and_remove_bus_device_locked+0x16/0x30 > remove_store+0xcf/0xe0 > > In the idxd_remove() flow, when execution reaches > idxd_unregister_devices(), all idxd_wq instances have already been > freed. Subsequently, when device_unregister(idxd_confdev(idxd)) is > executed, it calls into idxd_device_drv_remove() which accesses the > already-freed idxd_wq. This fix resolves the issue by calling > device_release_driver() before idxd_unregister_devices(). > > Fixes: 98da0106aac0d ("dmanegine: idxd: fix resource free ordering on driver removal") > Co-developed-by: Shuai Xue > Signed-off-by: Shuai Xue > Signed-off-by: Guixin Liu > --- > v1 -> v2: > 1. Call device_release_driver() in advance instead of swapping the order of > device_unregister() and idxd_unregister_devices(). > 2. Add Co-developed-by: Shuai Xue . > drivers/dma/idxd/init.c | 27 ++++++++++++++++++++++----- > 1 file changed, 22 insertions(+), 5 deletions(-) > > diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c > index f1cfc7790d95..3b0a0363ca65 100644 > --- a/drivers/dma/idxd/init.c > +++ b/drivers/dma/idxd/init.c > @@ -1293,13 +1293,30 @@ static void idxd_remove(struct pci_dev *pdev) > { > struct idxd_device *idxd = pci_get_drvdata(pdev); > > + /* > + * The idxd sub-driver's remove callback (idxd_device_drv_remove()) > + * iterates idxd->wqs[] and accesses wq objects. We must unbind the > + * sub-driver before idxd_unregister_devices() frees these objects, > + * otherwise a use-after-free occurs. > + * > + * We cannot simply reorder device_unregister(idxd_confdev) before > + * idxd_unregister_devices() because device_del() -> kobject_del() > + * recursively removes the parent's sysfs directory, which destroys > + * children's sysfs entries. Subsequent device_unregister() on the > + * children then fails with "sysfs group 'power' not found". > + * > + * Use device_release_driver() to only unbind the driver (triggering > + * idxd_device_drv_remove()) without touching sysfs. Then safely > + * unregister children before the parent. > + */ > + device_release_driver(idxd_confdev(idxd)); > idxd_unregister_devices(idxd); > + > /* > - * When ->release() is called for the idxd->conf_dev, it frees all the memory related > - * to the idxd context. The driver still needs those bits in order to do the rest of > - * the cleanup. However, we do need to unbound the idxd sub-driver. So take a ref > - * on the device here to hold off the freeing while allowing the idxd sub-driver > - * to unbind. > + * When ->release() is called for the idxd->conf_dev, it frees all the > + * memory related to the idxd context. The driver still needs those bits > + * in order to do the rest of the cleanup. So take a ref on the device > + * here to hold off the freeing. > */ > get_device(idxd_confdev(idxd)); > device_unregister(idxd_confdev(idxd));