From 64460af009888ede363c6284cef706c3e04cec24 Mon Sep 17 00:00:00 2001 From: Kuen-Han Tsai Date: Mon, 9 Mar 2026 20:04:47 +0800 Subject: Revert "usb: legacy: ncm: Fix NPE in gncm_bind" commit f2524c0e6ff0a5f72f1e1a32441c69d3b56430c4 upstream. This reverts commit fde0634ad9856b3943a2d1a8cc8de174a63ac840. This commit is being reverted as part of a series-wide revert. By deferring the net_device allocation to the bind() phase, a single function instance will spawn multiple network devices if it is symlinked to multiple USB configurations. This causes regressions for userspace tools (like the postmarketOS DHCP daemon) that rely on reading the interface name (e.g., "usb0") from configfs. Currently, configfs returns the template "usb%d", causing the userspace network setup to fail. Crucially, because this patch breaks the 1:1 mapping between the function instance and the network device, this naming issue cannot simply be patched. Configfs only exposes a single 'ifname' attribute per instance, making it impossible to accurately report the actual interface name when multiple underlying network devices can exist for that single instance. All configurations tied to the same function instance are meant to share a single network device. Revert this change to restore the 1:1 mapping by allocating the network device at the instance level (alloc_inst). Reported-by: David Heidelberg Closes: https://lore.kernel.org/linux-usb/70b558ea-a12e-4170-9b8e-c951131249af@ixit.cz/ Fixes: 56a512a9b410 ("usb: gadget: f_ncm: align net_device lifecycle with bind/unbind") Cc: stable Signed-off-by: Kuen-Han Tsai Link: https://patch.msgid.link/20260309-f-ncm-revert-v2-2-ea2afbc7d9b2@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/legacy/ncm.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/drivers/usb/gadget/legacy/ncm.c b/drivers/usb/gadget/legacy/ncm.c index e8d565534053..0f1b45e3abd1 100644 --- a/drivers/usb/gadget/legacy/ncm.c +++ b/drivers/usb/gadget/legacy/ncm.c @@ -15,10 +15,8 @@ /* #define DEBUG */ /* #define VERBOSE_DEBUG */ -#include #include #include -#include #include #include "u_ether.h" @@ -131,7 +129,6 @@ static int gncm_bind(struct usb_composite_dev *cdev) struct usb_gadget *gadget = cdev->gadget; struct f_ncm_opts *ncm_opts; int status; - u8 mac[ETH_ALEN]; f_ncm_inst = usb_get_function_instance("ncm"); if (IS_ERR(f_ncm_inst)) @@ -139,15 +136,11 @@ static int gncm_bind(struct usb_composite_dev *cdev) ncm_opts = container_of(f_ncm_inst, struct f_ncm_opts, func_inst); - ncm_opts->net_opts.qmult = qmult; - if (host_addr && mac_pton(host_addr, mac)) { - memcpy(&ncm_opts->net_opts.host_mac, mac, ETH_ALEN); + gether_set_qmult(ncm_opts->net, qmult); + if (!gether_set_host_addr(ncm_opts->net, host_addr)) pr_info("using host ethernet address: %s", host_addr); - } - if (dev_addr && mac_pton(dev_addr, mac)) { - memcpy(&ncm_opts->net_opts.dev_mac, mac, ETH_ALEN); + if (!gether_set_dev_addr(ncm_opts->net, dev_addr)) pr_info("using self ethernet address: %s", dev_addr); - } /* Allocate string descriptor numbers ... note that string * contents can be overridden by the composite_dev glue. -- cgit v1.2.3