kernel/linux.git/drivers/usb/gadget/function/u_ether.c, branch v6.18.22

usb: gadget: u_ether: Fix NULL pointer deref in eth_get_drvinfo

2026-04-11T12:26:49+00:00

commit e002e92e88e12457373ed096b18716d97e7bbb20 upstream. Commit ec35c1969650 ("usb: gadget: f_ncm: Fix net_device lifecycle with device_move") reparents the gadget device to /sys/devices/virtual during unbind, clearing the gadget pointer. If the userspace tool queries on the surviving interface during this detached window, this leads to a NULL pointer dereference. Unable to handle kernel NULL pointer dereference Call trace: eth_get_drvinfo+0x50/0x90 ethtool_get_drvinfo+0x5c/0x1f0 __dev_ethtool+0xaec/0x1fe0 dev_ethtool+0x134/0x2e0 dev_ioctl+0x338/0x560 Add a NULL check for dev->gadget in eth_get_drvinfo(). When detached, skip copying the fw_version and bus_info strings, which is natively handled by ethtool_get_drvinfo for empty strings. Suggested-by: Val Packett Reported-by: Val Packett Closes: https://lore.kernel.org/linux-usb/10890524-cf83-4a71-b879-93e2b2cc1fcc@packett.cool/ Fixes: ec35c1969650 ("usb: gadget: f_ncm: Fix net_device lifecycle with device_move") Cc: stable Signed-off-by: Kuen-Han Tsai Link: https://patch.msgid.link/20260316-eth-null-deref-v1-1-07005f33be85@google.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: u_ether: Fix race between gether_disconnect and eth_stop

2026-04-11T12:26:49+00:00

commit e1eabb072c75681f78312c484ccfffb7430f206e upstream. A race condition between gether_disconnect() and eth_stop() leads to a NULL pointer dereference. Specifically, if eth_stop() is triggered concurrently while gether_disconnect() is tearing down the endpoints, eth_stop() attempts to access the cleared endpoint descriptor, causing the following NPE: Unable to handle kernel NULL pointer dereference Call trace: __dwc3_gadget_ep_enable+0x60/0x788 dwc3_gadget_ep_enable+0x70/0xe4 usb_ep_enable+0x60/0x15c eth_stop+0xb8/0x108 Because eth_stop() crashes while holding the dev->lock, the thread running gether_disconnect() fails to acquire the same lock and spins forever, resulting in a hardlockup: Core - Debugging Information for Hardlockup core(7) Call trace: queued_spin_lock_slowpath+0x94/0x488 _raw_spin_lock+0x64/0x6c gether_disconnect+0x19c/0x1e8 ncm_set_alt+0x68/0x1a0 composite_setup+0x6a0/0xc50 The root cause is that the clearing of dev->port_usb in gether_disconnect() is delayed until the end of the function. Move the clearing of dev->port_usb to the very beginning of gether_disconnect() while holding dev->lock. This cuts off the link immediately, ensuring eth_stop() will see dev->port_usb as NULL and safely bail out. Fixes: 2b3d942c4878 ("usb ethernet gadget: split out network core") Cc: stable Signed-off-by: Kuen-Han Tsai Link: https://patch.msgid.link/20260311-gether-disconnect-npe-v1-1-454966adf7c7@google.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_ncm: Fix net_device lifecycle with device_move

2026-03-19T15:08:28+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"

2026-03-19T15:08:28+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"

2026-03-19T15:08:28+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

2026-03-12T11:09:25+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

2026-03-12T11:09:25+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