From nobody Mon Jun 8 07:24:54 2026 Received: from outbound.baidu.com (mx15.baidu.com [111.202.115.100]) by smtp.subspace.kernel.org (Postfix) with SMTP id 6B7A8375F8E for ; Mon, 1 Jun 2026 12:12:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=111.202.115.100 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780315982; cv=none; b=WRbd5DNMblVVHNJfy6nFw0NYyCeYICg4W95YwGqt5bL1A7v8NFpPI4OTsT9fni6yMjZ2eG5/C6O6nLZmqnJyESPZxdQRWvFryUH074JNpfIjn6iUhBrzub1QK2ZaSpZZVm7e/aOWt0UjHp2YYWxIlI8hL/FLj6mso9p63JXgjYw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780315982; c=relaxed/simple; bh=LZJ8Svuo7djBDxLwtuMAwakmdGCCC+ETcnBOs2yKNWI=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=WsnEWHJ4EiQqbTkxrlrTAtECLZFxaueGA2PDkWccUzlTElC3qTXnFCoRguGYLsPFqkpSMmP6Hnd4yfvgqn+FugHn6/HzoALCANhZxSLeWsIaUJVZ6N32HMiS3Wfon2nsiJ+rgN6tf6IWHpB8z2CdHJ72CP2b1B5DTfM24lFI/3k= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=baidu.com; spf=pass smtp.mailfrom=baidu.com; dkim=pass (2048-bit key) header.d=baidu.com header.i=@baidu.com header.b=OdYH6Aab; arc=none smtp.client-ip=111.202.115.100 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=baidu.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=baidu.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=baidu.com header.i=@baidu.com header.b="OdYH6Aab" X-MD-Sfrom: lirongqing@baidu.com X-MD-SrcIP: 172.31.50.47 From: lirongqing To: Joerg Roedel , Suravee Suthikulpanit , Will Deacon , Robin Murphy , , CC: Li RongQing Subject: [PATCH] iommu/amd: Fix undefined behavior in devid_write debugfs function Date: Mon, 1 Jun 2026 08:12:40 -0400 Message-ID: <20260601121240.2474-1-lirongqing@baidu.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: bjkjy-exc8.internal.baidu.com (172.31.50.52) To bjkjy-exc3.internal.baidu.com (172.31.50.47) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baidu.com; s=selector1; t=1780315968; bh=pmI+Zw4RALLO9MTnTkIO8f3Iqt538OVzYC3v96E48l0=; h=From:To:CC:Subject:Date:Message-ID:Content-Type; b=OdYH6AabmK1BNGv1pmmxDIjT6ndf62OqYhl7G6JP1Yyud4TcWz1zPsg9/i2AQ0xVU 6nAF03pqJYDEt490YaB2lA7UPNX860HRxVW5LnfK78RtDm1sdi9mtbxCAoBifIG5So NmXJAF6kFymPX9GOb6eZgmoOdhDHkJ3P3stPORrTv0CLt3nmyAJghsJaW/9Uy/Zhqw PW7vs02aRylUNsXZzBZpTJdfEIozJyOSMejDlAgERKdozJXIvFngHvCBCOJTfJjmiA 2pjeBcDTpvpyd4dS859S5WRkpSpaeoV6+6CIPReIaxiN+sZjfIzQvpXA8rLWVRE5ap giiP6Uy1VkxHQ== Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Li RongQing When for_each_pci_segment() loop completes without finding a matching segment, the pci_seg pointer is not NULL but points to an invalid memory location (the list head). Accessing pci_seg->id after the loop causes undefined behavior. Fix this by handling the successful case inside the loop and returning -EINVAL after the loop if no matching segment is found. Fixes: 2e98940f123d9 ("iommu/amd: Add support for device id user input") Signed-off-by: Li RongQing Reviewed-by: Ankit Soni --- drivers/iommu/amd/debugfs.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/drivers/iommu/amd/debugfs.c b/drivers/iommu/amd/debugfs.c index 4c53b63..5c573ec 100644 --- a/drivers/iommu/amd/debugfs.c +++ b/drivers/iommu/amd/debugfs.c @@ -176,19 +176,13 @@ static ssize_t devid_write(struct file *filp, const c= har __user *ubuf, kfree(srcid_ptr); return -ENODEV; } - break; - } - - if (pci_seg->id !=3D seg) { + sbdf =3D PCI_SEG_DEVID_TO_SBDF(seg, devid); kfree(srcid_ptr); - return -EINVAL; + return cnt; } =20 - sbdf =3D PCI_SEG_DEVID_TO_SBDF(seg, devid); - kfree(srcid_ptr); - - return cnt; + return -EINVAL; } =20 static int devid_show(struct seq_file *m, void *unused) --=20 2.9.4