From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com [115.124.30.132]) (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 1EDB93233F4 for ; Wed, 15 Apr 2026 09:50:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.132 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776246641; cv=none; b=oJPJPbP0V+J2vU0zCFIEalH8K3vnE5jBDew+JIR5aD3feOyNoPiklRt+QfOH0XoAfQUg0vN8SvTQ6qqBwjHFc4XnYy1WoxZJe26dnRuHlXxNaM5H9QzeGG4o46nE2ueYFK4lQAZwJToxkYPamVWvEGuNhlKi/N+7pYimQcdy1YA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776246641; c=relaxed/simple; bh=Na3ynCYv05nuk4wg7pwsJ2ux5izRFSMzOdJJ3jiP7UE=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=k661YyvQoLvfpVm8yZeTVstRLfnXiJvjeXxXefhCzpLEiE86BMNXVEGdVbdZkw37KYbWlzELVY5Zli82HyJwxTxwZH65if9kQLtChIDTehXhU2LNGBlQxuRvW4VMbCba7gv7VSO3/bZg3Q6Efd5eTS17LfG/T08i6rVT7HLSva8= 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=yls1HZOS; arc=none smtp.client-ip=115.124.30.132 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="yls1HZOS" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1776246635; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=OlI6MOChUhyVGR/3erRzPfG1tIlWmX7mMb855eECKVw=; b=yls1HZOSP7PEUNq2S4HotCf6DfbkbF21u+5ZHeMZBX1zHyrYuqPlZHZXMHEhmj51/bnEqYDiXdTfEo017Q0991Pp8h/UTc8Y07s3r8YjYny0FYf1YQ7q+MpS2hYGZ5xE/T7wWs1ksDRhyr2y0M51+IjmUlDFKl3X3iWGQPUDjvU= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R201e4;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_---0X14IUcA_1776246630; Received: from localhost(mailfrom:kanie@linux.alibaba.com fp:SMTPD_---0X14IUcA_1776246630 cluster:ay36) by smtp.aliyun-inc.com; Wed, 15 Apr 2026 17:50:35 +0800 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 Subject: [PATCH v2] dmaengine: idxd: Fix use-after-free of idxd_wq Date: Wed, 15 Apr 2026 17:50:30 +0800 Message-Id: <20260415095030.42183-1-kanie@linux.alibaba.com> X-Mailer: git-send-email 2.32.0.3.g01195cf9f Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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)); -- 2.32.0.3.g01195cf9f