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 AC98440BCDA; Fri, 4 Sep 2026 05:08:48 +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=1788498529; cv=none; b=dqUx0S5pfgHU+mnxCXfnrjwiqZFMo7nJMW3gZ7whJQgjUde5GTRYuR1wYgtMD/Rg1Bv1g0QMk/i2B2x/aZQnYeRCgrRRBQZ9bircJK3i+x4yzwJwsUbNinVO+d+273QdphZ989xe4qSaeSPR32voSYxpJfsALnJMFS72eSeRmB0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788498529; c=relaxed/simple; bh=lvzD/nzs9fHXm4QUiOFGt/yNK6nTFNpq0c5YNk/PyRQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=QPEJaYfsoygCfW7QI3Pxxq7e8pvh6sO+6fISKljBDUiv79OTH9qyvn5mpuAuNIvwW3ETMu+l+NrhESWl2ORftOGmCOxOm4HJqSll7TCsMHOg1XQXmzcVHOcEUa/JKFqgWkIbbhRBR69JG2bP0yBwCVkDa1MLa12B6kxFn03O/Hg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PY0f1rXX; 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="PY0f1rXX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC6681F00A3D; Fri, 4 Sep 2026 05:08:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788498528; bh=ZZzybR5d/VYgUbLIXNuRtz0tYlqxc88Qoh71mCfIQbY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=PY0f1rXXMPZ8JiL8Fh8s1aJiuZkrfvg8x+2UHQoyeMvf41OrR0npYWTvLQIkNCcYv kBpxmkBGVm0oIvCmy0jQY47maf7sVLaWShLd94E9H+2Qu5TA6jNygjm52lE4VARY29 OhQ9mVDWPZgX/iyYtu7261u6LkPWiX3ptjEk656o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xu Yang , Andy Shevchenko Subject: [PATCH 7.2 096/713] device property: fix infinite loop in fwnode_for_each_child_node() Date: Fri, 4 Sep 2026 06:51:04 +0200 Message-ID: <20260904045805.990557492@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045803.810145556@linuxfoundation.org> References: <20260904045803.810145556@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 7.2-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 @@ -807,18 +807,31 @@ 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);