kernel/linux.git/drivers/usb/gadget/function/u_ether.c, branch v6.19.11

usb: gadget: f_ncm: Fix net_device lifecycle with device_move

2026-03-19T15:15:06+00:00

commit ec35c1969650e7cb6c8a91020e568ed46e3551b0 upstream. The network device outlived its parent gadget device during disconnection, resulting in dangling sysfs links and null pointer dereference problems. A prior attempt to solve this by removing SET_NETDEV_DEV entirely [1] was reverted due to power management ordering concerns and a NO-CARRIER regression. A subsequent attempt to defer net_device allocation to bind [2] broke 1:1 mapping between function instance and network device, making it impossible for configfs to report the resolved interface name. This results in a regression where the DHCP server fails on pmOS. Use device_move to reparent the net_device between the gadget device and /sys/devices/virtual/ across bind/unbind cycles. This preserves the network interface across USB reconnection, allowing the DHCP server to retain their binding. Introduce gether_attach_gadget()/gether_detach_gadget() helpers and use __free(detach_gadget) macro to undo attachment on bind failure. The bind_count ensures device_move executes only on the first bind. [1] https://lore.kernel.org/lkml/f2a4f9847617a0929d62025748384092e5f35cce.camel@crapouillou.net/ [2] https://lore.kernel.org/linux-usb/795ea759-7eaf-4f78-81f4-01ffbf2d7961@ixit.cz/ Fixes: 40d133d7f542 ("usb: gadget: f_ncm: convert to new function interface with backward compatibility") Cc: stable Signed-off-by: Kuen-Han Tsai Link: https://patch.msgid.link/20260309-f-ncm-revert-v2-7-ea2afbc7d9b2@google.com Signed-off-by: Greg Kroah-Hartman

Revert "usb: gadget: u_ether: add gether_opts for config caching"

2026-03-19T15:15:06+00:00

commit 3131c1aff7cdffb96239f06f98e16188cbc2083f upstream. This reverts commit e065c6a7e46c2ee9c677fdbf50035323d2de1215. 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-v2-6-ea2afbc7d9b2@google.com Signed-off-by: Greg Kroah-Hartman

Revert "usb: gadget: u_ether: Add auto-cleanup helper for freeing net_device"

2026-03-19T15:15:06+00:00

commit 46662d3a1ad40282ba9f753cccc6f909ec4468cc upstream. This reverts commit 0c0981126b99288ed354d3d414c8a5fd42ac9e25. 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-v2-4-ea2afbc7d9b2@google.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: u_ether: Add auto-cleanup helper for freeing net_device

2026-03-12T11:09:26+00:00

[ Upstream commit 0c0981126b99288ed354d3d414c8a5fd42ac9e25 ] The net_device in the u_ether framework currently requires explicit calls to unregister and free the device. Introduce gether_unregister_free_netdev() and the corresponding auto-cleanup macro. This ensures that if a net_device is registered, it is properly unregistered and the associated work queue is flushed before the memory is freed. This is a preparatory patch to simplify error handling paths in gadget drivers by removing the need for explicit goto labels for net_device cleanup. Signed-off-by: Kuen-Han Tsai Link: https://patch.msgid.link/20251230-ncm-refactor-v1-2-793e347bc7a7@google.com Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 56a512a9b410 ("usb: gadget: f_ncm: align net_device lifecycle with bind/unbind") Signed-off-by: Sasha Levin

usb: gadget: u_ether: add gether_opts for config caching

2026-03-12T11:09:26+00:00

[ Upstream commit e065c6a7e46c2ee9c677fdbf50035323d2de1215 ] Currently, the net_device is allocated when the function instance is created (e.g., in ncm_alloc_inst()). While this allows userspace to configure the device early, it decouples the net_device lifecycle from the actual USB connection state (bind/unbind). The goal is to defer net_device creation to the bind callback to properly align the lifecycle with its parent gadget device. However, deferring net_device allocation would prevent userspace from configuring parameters (like interface name or MAC address) before the net_device exists. Introduce a new structure, struct gether_opts, associated with the usb_function_instance, to cache settings independently of the net_device. These settings include the interface name pattern, MAC addresses (device and host), queue multiplier, and address assignment type. New helper functions are added: - gether_setup_opts_default(): Initializes struct gether_opts with defaults, including random MAC addresses. - gether_apply_opts(): Applies the cached options from a struct gether_opts to a valid net_device. To expose these options to userspace, new configfs macros (USB_ETHER_OPTS_ITEM and USB_ETHER_OPTS_ATTR_*) are defined in u_ether_configfs.h. These attributes are part of the function instance's configfs group. This refactoring is a preparatory step. It allows the subsequent patch to safely move the net_device allocation from the instance creation phase to the bind phase without losing the ability to pre-configure the interface via configfs. Signed-off-by: Kuen-Han Tsai Link: https://patch.msgid.link/20251230-ncm-refactor-v1-1-793e347bc7a7@google.com Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 56a512a9b410 ("usb: gadget: f_ncm: align net_device lifecycle with bind/unbind") Signed-off-by: Sasha Levin

usb: gadget: u_ether: Set is_suspend flag if remote wakeup fails

2025-02-19T14:18:41+00:00

Currently while UDC suspends, u_ether attempts to remote wakeup the host if there are any pending transfers. However, if remote wakeup fails, the UDC remains suspended but the is_suspend flag is not set. And since is_suspend flag isn't set, the subsequent eth_start_xmit() would queue USB requests to suspended UDC. To fix this, bail out from gether_suspend() only if remote wakeup operation is successful. Cc: stable Fixes: 0a1af6dfa077 ("usb: gadget: f_ecm: Add suspend/resume and remote wakeup support") Signed-off-by: Prashanth K Link: https://lore.kernel.org/r/20250212100840.3812153-1-prashanth.k@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman

Merge 6.10-rc6 into usb-next

2024-07-01T11:59:29+00:00

We need the USB fixes in here as well for some follow-on patches. Signed-off-by: Greg Kroah-Hartman

Revert "usb: gadget: u_ether: Replace netif_stop_queue with netif_device_detach"

2024-06-27T14:24:25+00:00

This reverts commit f49449fbc21e7e9550a5203902d69c8ae7dfd918. This commit breaks u_ether on some setups (at least Merrifield). The fix "usb: gadget: u_ether: Re-attach netif device to mirror detachment" party restores u-ether. However the netif usb: remains up even usb is switched from device to host mode. This creates problems for user space as the interface remains in the routing table while not realy present and network managers (connman) not detecting a network change. Various attempts to find the root cause were unsuccesful up to now. Therefore revert until a solution is found. Link: https://lore.kernel.org/linux-usb/20231006141231.7220-1-hgajjar@de.adit-jv.com/ Reported-by: Andy Shevchenko Reported-by: Ferry Toth Fixes: f49449fbc21e ("usb: gadget: u_ether: Replace netif_stop_queue with netif_device_detach") Cc: stable@vger.kernel.org Signed-off-by: Ferry Toth Link: https://lore.kernel.org/r/20240620204832.24518-3-ftoth@exalondelft.nl Signed-off-by: Greg Kroah-Hartman

Revert "usb: gadget: u_ether: Re-attach netif device to mirror detachment"

2024-06-27T14:24:25+00:00

This reverts commit 76c945730cdffb572c7767073cc6515fd3f646b4. Prerequisite revert for the reverting of the original commit f49449fbc21e. Fixes: 76c945730cdf ("usb: gadget: u_ether: Re-attach netif device to mirror detachment") Fixes: f49449fbc21e ("usb: gadget: u_ether: Replace netif_stop_queue with netif_device_detach") Reported-by: Ferry Toth Cc: stable@vger.kernel.org Signed-off-by: Ferry Toth Link: https://lore.kernel.org/r/20240620204832.24518-2-ftoth@exalondelft.nl Signed-off-by: Greg Kroah-Hartman

usb: gadget: add missing MODULE_DESCRIPTION() macros

2024-06-20T17:18:19+00:00

make allmodconfig && make W=1 C=1 reports: WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/libcomposite.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_acm.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_ss_lb.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/u_serial.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_serial.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_obex.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/u_ether.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_ncm.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_ecm.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_phonet.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_eem.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_ecm_subset.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_rndis.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_mass_storage.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_fs.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_uac1.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_uac1_legacy.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_uac2.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_uvc.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_midi.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_midi2.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_hid.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_printer.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/function/usb_f_tcm.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/legacy/g_zero.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/legacy/g_midi.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/usb/gadget/legacy/g_dbgp.o Add the missing invocations of the MODULE_DESCRIPTION() macro. Signed-off-by: Jeff Johnson Link: https://lore.kernel.org/r/20240605-md-drivers-usb-gadget-v1-1-29847a46aad3@quicinc.com Signed-off-by: Greg Kroah-Hartman