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 2AF4E33A9E2; Sat, 12 Sep 2026 15:27:29 +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=1789226850; cv=none; b=QBcBD0s9JwTQIS7Qka2M887qIDpJnvn/mDuiYhzQrOuTZr8lGNuvw6HA0QiJzgCheRf3yXp/5FEK7UXlS1nrC3Ddnd5gFLpjItRThU0IUniiF8Wc+m+G0//VUE9dEUA/cc9d66Ptj89gBSd0s/Ev0C4ej4+8joZZcJFnw0T1oAU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789226850; c=relaxed/simple; bh=NjCwr4sBFcmaUE/fvuzZh+319looUStTZlU63Ya2/1g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=CpY1vfGjlkGkwI9xzTqAx+vbz0SzwlLtL7Up1WT+xOeffZRjAeYqexmovuwJeOi7PKaX0lxrWnfY/vTVTCYZVtpaY8JfnnDvvOA6PM8J8nfBcl2T3w144Lkut0A5MpXoX68fKWXWilfTeJrRwyF1N0skkSuX5jNtD96i/Ns/bbQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=KUJ2xeUC; 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="KUJ2xeUC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BDE091F000FF; Sat, 12 Sep 2026 15:27:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789226849; bh=dO+ttp/VSaQiQ0o2rvtoCgXcAfSImK4C/UVjG44pTUM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=KUJ2xeUCy9v+b6P+nCWa1JqPHyCfF0G3Tl2CqSiioX25w1qBedazXg7+o1TUck1s9 fn9XKwukvdvK3MZMCoBOjmeUsrTZIXV7EF5wKCS2XWIuQv0cosWiPxPCheJbubwGws jopbDsVaLBZCCXouiYinnkGG/KVO+YQKIhQxZxWk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xu Yang , Andy Shevchenko Subject: [PATCH 6.1 0018/1191] device property: fix infinite loop in fwnode_for_each_child_node() Date: Sat, 12 Sep 2026 08:45:46 +0200 Message-ID: <20260912065548.520026892@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065548.086904252@linuxfoundation.org> References: <20260912065548.086904252@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xu Yang commit 1900692555826753adab8799a1a8d50bb1ee200c upstream. When iterate over children of a fwnode that has a secondary fwnode, fwnode_get_next_child_node() can enter an infinite loop if the secondary fwnode has more than one child. Parent Child (Primary fwnode) FWa: {FWa1, FWa2, FWa3} (Secondary fwnode) FWb: {FWb1, FWb2} In this case: ┌─> fwnode_get_next_child_node(FWa, FWa1) │ - fwnode_call_ptr_op(FWa, get_next_child_node, FWa1) returns FWa2 │ │ ... │ │ fwnode_get_next_child_node(FWa, FWa3) │ - fwnode_call_ptr_op(FWa, get_next_child_node, FWa3) returns NULL │ - fwnode_call_ptr_op(FWb, get_next_child_node, FWa3) returns FWb1 │ │ fwnode_get_next_child_node(FWa, FWb1) │ - fwnode_call_ptr_op(FWa, get_next_child_node, FWb1) returns FWa1 └────┘ This cause fwnode_for_each_child_node() to loop indefinitely, reapeatedly output {FWa1, FWa2, FWa3, FWb1, FWa1, ...}. The root cause is that when the current child (FWb1) belongs to the secondary fwnode, calling get_next_child_node() on the parimary fwnode incorrectly returns the first child (FWa1) again instead of NULL. Fix this by dynamically checking the parent fwnode of the current child before calling get_next_child_node(). This approach follows the pattern established in commit b5b41ab6b0c1 ("device property: Check fwnode->secondary in fwnode_graph_get_next_endpoint()"). Fixes: 2692c614f8f0 ("device property: Allow secondary lookup in fwnode_get_next_child_node()") Cc: stable@vger.kernel.org Signed-off-by: Xu Yang Tested-by: Andy Shevchenko Signed-off-by: Andy Shevchenko Tested-by: Xu Yang Link: https://patch.msgid.link/20260611203537.1786399-2-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/base/property.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) --- a/drivers/base/property.c +++ b/drivers/base/property.c @@ -749,18 +749,31 @@ struct fwnode_handle * fwnode_get_next_child_node(const struct fwnode_handle *fwnode, struct fwnode_handle *child) { + const struct fwnode_handle *parent; + struct fwnode_handle *child_parent __free(fwnode_handle) = NULL; struct fwnode_handle *next; - if (IS_ERR_OR_NULL(fwnode)) + /* + * If this function is in a loop and the previous iteration returned + * an child from fwnode->secondary, then we need to use the secondary + * as parent rather than @fwnode. + */ + if (child) { + child_parent = fwnode_get_parent(child); + parent = child_parent; + } else { + parent = fwnode; + } + if (IS_ERR_OR_NULL(parent)) return NULL; /* Try to find a child in primary fwnode */ - next = fwnode_call_ptr_op(fwnode, get_next_child_node, child); + next = fwnode_call_ptr_op(parent, get_next_child_node, child); if (next) return next; /* When no more children in primary, continue with secondary */ - return fwnode_call_ptr_op(fwnode->secondary, get_next_child_node, child); + return fwnode_get_next_child_node(parent->secondary, NULL); } EXPORT_SYMBOL_GPL(fwnode_get_next_child_node);