From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 704A530171C for ; Wed, 20 May 2026 14:46:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779288384; cv=none; b=epBbYg5XAGm3NOzm/SbfhHHmNbn5BNRoRiPE48RmVROx6flGmiCOr2BqUHPY7ORXR8x/uDQ4PWr3EDRWDJ5TjUTXnJIR6GrU4je3zGds3588Yir5gEWPnoQJ2NEsI612J0eG2d0j+5kWyrklG56cYhhwiIQMQL54GGTTIs5p1Tk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779288384; c=relaxed/simple; bh=5s1ob1axP2YyvOlMlJO+COIQ0RFrxi/frqiijfVuST8=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=HnzmKzbyifdqHM2bBdwYcGIPtoD+DbK757tt11DbD4qH1xMfNNMV8avmu8FpuAQPHz6NnnJ4K60kYmipWiwld56Bd+NfQRbqtjeX8Zt7p/hmLOFiIlW0LwWLlVe/rXwZQz7Pn35gukX0a1AOM2kweOKfWchfdjtau9Hq1RffBtg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lK9RUw7X; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="lK9RUw7X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E79F1F000E9; Wed, 20 May 2026 14:46:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779288383; bh=5PyQs+3e7JRPui4jjIPZloQVMMkpy2mhOLCmaXXInIY=; h=Subject:To:Cc:From:Date; b=lK9RUw7XBagKg6mCBYa+B42g1OFfcPZefyPZQFKaNvBnjetgfX8Yd/IDrABiBtepi 8oi6syzxG/WW12gCYdISoH7KbClXgpdX7CZZvy/5J4hS3/QZiszVBoN1HRjtHeRKI2 wlQY1FFeEaH5xnFIdRubgyhsQ5L19RPHclAe82oA= Subject: FAILED: patch "[PATCH] iommu/vt-d: Avoid NULL pointer dereference or refcount" failed to apply to 6.12-stable tree To: zhenzhong.duan@intel.com,baolu.lu@linux.intel.com,joerg.roedel@amd.com,kevin.tian@intel.com Cc: From: Date: Wed, 20 May 2026 16:46:18 +0200 Message-ID: <2026052018-tamper-duchess-b780@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 79ea2feb917b05366b49d85573c9c5331f043b2c # git commit -s git send-email --to '' --in-reply-to '2026052018-tamper-duchess-b780@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 79ea2feb917b05366b49d85573c9c5331f043b2c Mon Sep 17 00:00:00 2001 From: Zhenzhong Duan Date: Sat, 9 May 2026 10:43:46 +0800 Subject: [PATCH] iommu/vt-d: Avoid NULL pointer dereference or refcount corruption Commit 60f030f7418d ("iommu/vt-d: Avoid use of NULL after WARN_ON_ONCE") fixed a NULL pointer dereference in an unlikely situation partly. If dev_pasid is not found in the dev_pasids list, it remains NULL. However, the teardown operations are executed unconditionally, this lead to a NULL pointer dereference or refcount corruption. If the domain was never attached to this IOMMU, info will be NULL, which would cause an immediate dereference when checking --info->refcnt. Even if info is not NULL, decrementing the refcount without having removed a valid PASID might unbalance the count. This could lead to premature dropping of the refcount to 0, potentially causing a use-after-free for the remaining active devices sharing the domain. Fix it by returning early if dev_pasid is NULL, before executing the teardown operations. Issue found by AI review and suggested by Kevin Tian. https://sashiko.dev/#/patchset/20260421031347.1408890-1-zhenzhong.duan%40intel.com Fixes: 60f030f7418d ("iommu/vt-d: Avoid use of NULL after WARN_ON_ONCE") Cc: stable@vger.kernel.org Suggested-by: Kevin Tian Signed-off-by: Zhenzhong Duan Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/20260422033538.95000-1-zhenzhong.duan@intel.com Signed-off-by: Lu Baolu Signed-off-by: Joerg Roedel diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index a4b123c33022..4d0e65bc131d 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -3545,12 +3545,13 @@ void domain_remove_dev_pasid(struct iommu_domain *domain, } spin_unlock_irqrestore(&dmar_domain->lock, flags); + if (WARN_ON_ONCE(!dev_pasid)) + return; + cache_tag_unassign_domain(dmar_domain, dev, pasid); domain_detach_iommu(dmar_domain, iommu); - if (!WARN_ON_ONCE(!dev_pasid)) { - intel_iommu_debugfs_remove_dev_pasid(dev_pasid); - kfree(dev_pasid); - } + intel_iommu_debugfs_remove_dev_pasid(dev_pasid); + kfree(dev_pasid); } static int blocking_domain_set_dev_pasid(struct iommu_domain *domain,