kernel/linux.git/drivers/net/usb/usbnet.c, branch linux-7.0.y

qmi_wwan: allow max_mtu above hard_mtu to control rx_urb_size

2026-03-07T00:31:41+00:00

Commit c7159e960f14 ("usbnet: limit max_mtu based on device's hard_mtu") capped net->max_mtu to the device's hard_mtu in usbnet_probe(). While this correctly prevents oversized packets on standard USB network devices, it breaks the qmi_wwan driver. qmi_wwan relies on userspace (e.g. ModemManager) setting a large MTU on the wwan0 interface to configure rx_urb_size via usbnet_change_mtu(). QMI modems negotiate USB transfer sizes of 16,383 or 32,767 bytes, and the USB receive buffers must be sized accordingly. With max_mtu capped to hard_mtu (~1500 bytes), userspace can no longer raise the MTU, the receive buffers remain small, and download speeds drop from >300 Mbps to ~0.8 Mbps. Introduce a FLAG_NOMAXMTU driver flag that allows individual usbnet drivers to opt out of the max_mtu cap. Set this flag in qmi_wwan's driver_info structures to restore the previous behavior for QMI devices, while keeping the safety fix in place for all other usbnet drivers. Fixes: c7159e960f14 ("usbnet: limit max_mtu based on device's hard_mtu") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/CAPh3n803k8JcBPV5qEzUB-oKzWkAs-D5CU7z=Vd_nLRCr5ZqQg@mail.gmail.com/ Reported-by: Koen Vandeputte Tested-by: Daniele Palmas Signed-off-by: Laurent Vivier Link: https://patch.msgid.link/20260304134338.1785002-1-lvivier@redhat.com Signed-off-by: Jakub Kicinski

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

Merge tag 'mm-nonmm-stable-2026-02-12-10-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-02-12T20:13:01+00:00

Pull non-MM updates from Andrew Morton: - "ocfs2: give ocfs2 the ability to reclaim suballocator free bg" saves disk space by teaching ocfs2 to reclaim suballocator block group space (Heming Zhao) - "Add ARRAY_END(), and use it to fix off-by-one bugs" adds the ARRAY_END() macro and uses it in various places (Alejandro Colomar) - "vmcoreinfo: support VMCOREINFO_BYTES larger than PAGE_SIZE" makes the vmcore code future-safe, if VMCOREINFO_BYTES ever exceeds the page size (Pnina Feder) - "kallsyms: Prevent invalid access when showing module buildid" cleans up kallsyms code related to module buildid and fixes an invalid access crash when printing backtraces (Petr Mladek) - "Address page fault in ima_restore_measurement_list()" fixes a kexec-related crash that can occur when booting the second-stage kernel on x86 (Harshit Mogalapalli) - "kho: ABI headers and Documentation updates" updates the kexec handover ABI documentation (Mike Rapoport) - "Align atomic storage" adds the __aligned attribute to atomic_t and atomic64_t definitions to get natural alignment of both types on csky, m68k, microblaze, nios2, openrisc and sh (Finn Thain) - "kho: clean up page initialization logic" simplifies the page initialization logic in kho_restore_page() (Pratyush Yadav) - "Unload linux/kernel.h" moves several things out of kernel.h and into more appropriate places (Yury Norov) - "don't abuse task_struct.group_leader" removes the usage of ->group_leader when it is "obviously unnecessary" (Oleg Nesterov) - "list private v2 & luo flb" adds some infrastructure improvements to the live update orchestrator (Pasha Tatashin) * tag 'mm-nonmm-stable-2026-02-12-10-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (107 commits) watchdog/hardlockup: simplify perf event probe and remove per-cpu dependency procfs: fix missing RCU protection when reading real_parent in do_task_stat() watchdog/softlockup: fix sample ring index wrap in need_counting_irqs() kcsan, compiler_types: avoid duplicate type issues in BPF Type Format kho: fix doc for kho_restore_pages() tests/liveupdate: add in-kernel liveupdate test liveupdate: luo_flb: introduce File-Lifecycle-Bound global state liveupdate: luo_file: Use private list list: add kunit test for private list primitives list: add primitives for private list manipulations delayacct: fix uapi timespec64 definition panic: add panic_force_cpu= parameter to redirect panic to a specific CPU netclassid: use thread_group_leader(p) in update_classid_task() RDMA/umem: don't abuse current->group_leader drm/pan*: don't abuse current->group_leader drm/amd: kill the outdated "Only the pthreads threading model is supported" checks drm/amdgpu: don't abuse current->group_leader android/binder: use same_thread_group(proc->tsk, current) in binder_mmap() android/binder: don't abuse current->group_leader kho: skip memoryless NUMA nodes when reserving scratch areas ...

net: usb: introduce usbnet_mii_ioctl helper function

2026-02-04T03:41:19+00:00

Many USB network drivers use identical code to pass ioctl requests on to the MII layer. Reduce code duplication by refactoring this code into a helper function. Reviewed-by: Vadim Fedorenko (v1) Reviewed-by: Andrew Lunn (v3) Signed-off-by: Ethan Nelson-Moore Reviewed-by: Andy Shevchenko Link: https://patch.msgid.link/20260203013517.26170-1-enelsonmoore@gmail.com Signed-off-by: Jakub Kicinski

kernel.h: drop hex.h and update all hex.h users

2026-01-21T03:44:19+00:00

Remove from and update all users/callers of hex.h interfaces to directly #include as part of the process of putting kernel.h on a diet. Removing hex.h from kernel.h means that 36K C source files don't have to pay the price of parsing hex.h for the roughly 120 C source files that need it. This change has been build-tested with allmodconfig on most ARCHes. Also, all users/callers of in the entire source tree have been updated if needed (if not already #included). Link: https://lkml.kernel.org/r/20251215005206.2362276-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap Reviewed-by: Andy Shevchenko Cc: Ingo Molnar Cc: Yury Norov (NVIDIA) Signed-off-by: Andrew Morton

usbnet: limit max_mtu based on device's hard_mtu

2026-01-21T02:58:54+00:00

The usbnet driver initializes net->max_mtu to ETH_MAX_MTU before calling the device's bind() callback. When the bind() callback sets dev->hard_mtu based the device's actual capability (from CDC Ethernet's wMaxSegmentSize descriptor), max_mtu is never updated to reflect this hardware limitation). This allows userspace (DHCP or IPv6 RA) to configure MTU larger than the device can handle, leading to silent packet drops when the backend sends packet exceeding the device's buffer size. Fix this by limiting net->max_mtu to the device's hard_mtu after the bind callback returns. See https://gitlab.com/qemu-project/qemu/-/issues/3268 and https://bugs.passt.top/attachment.cgi?bugid=189 Fixes: f77f0aee4da4 ("net: use core MTU range checking in USB NIC drivers") Signed-off-by: Laurent Vivier Link: https://bugs.passt.top/show_bug.cgi?id=189 Reviewed-by: Stefano Brivio Link: https://patch.msgid.link/20260119075518.2774373-1-lvivier@redhat.com Signed-off-by: Jakub Kicinski

usbnet: fix crash due to missing BQL accounting after resume

2026-01-16T03:40:59+00:00

In commit 7ff14c52049e ("usbnet: Add support for Byte Queue Limits (BQL)"), it was missed that usbnet_resume() may enqueue SKBs using __skb_queue_tail() without reporting them to BQL. As a result, the next call to netdev_completed_queue() triggers a BUG_ON() in dql_completed(), since the SKBs queued during resume were never accounted for. This patch fixes the issue by adding a corresponding netdev_sent_queue() call in usbnet_resume() when SKBs are queued after suspend. Because dev->txq.lock is held at this point, no concurrent calls to netdev_sent_queue() from usbnet_start_xmit() can occur. The crash can be reproduced by generating network traffic (e.g. iperf3 -c ... -t 0), suspending the system, and then waking it up (e.g. rtcwake -m mem -s 5). When testing USB2 Android tethering (cdc_ncm), the system crashed within three suspend/resume cycles without this patch. With the patch applied, no crashes were observed after 90 cycles. Testing with an AX88179 USB Ethernet adapter also showed no crashes. Fixes: 7ff14c52049e ("usbnet: Add support for Byte Queue Limits (BQL)") Reported-by: Bard Liao Tested-by: Bard Liao Tested-by: Simon Schippers Signed-off-by: Simon Schippers Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260113075139.6735-1-simon.schippers@tu-dortmund.de Signed-off-by: Jakub Kicinski

usbnet: avoid a possible crash in dql_completed()

2025-12-29T18:23:34+00:00

syzbot reported a crash [1] in dql_completed() after recent usbnet BQL adoption. The reason for the crash is that netdev_reset_queue() is called too soon. It should be called after cancel_work_sync(&dev->bh_work) to make sure no more TX completion can happen. [1] kernel BUG at lib/dynamic_queue_limits.c:99 ! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 1 UID: 0 PID: 5197 Comm: udevd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:dql_completed+0xbe1/0xbf0 lib/dynamic_queue_limits.c:99 Call Trace: netdev_tx_completed_queue include/linux/netdevice.h:3864 [inline] netdev_completed_queue include/linux/netdevice.h:3894 [inline] usbnet_bh+0x793/0x1020 drivers/net/usb/usbnet.c:1601 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 bh_worker+0x2b1/0x600 kernel/workqueue.c:3611 tasklet_action+0xc/0x70 kernel/softirq.c:952 handle_softirqs+0x27d/0x850 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 Fixes: 7ff14c52049e ("usbnet: Add support for Byte Queue Limits (BQL)") Reported-by: syzbot+5b55e49f8bbd84631a9c@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/6945644f.a70a0220.207337.0113.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Cc: Simon Schippers Link: https://patch.msgid.link/20251219144459.692715-1-edumazet@google.com Signed-off-by: Paolo Abeni

net: usb: usbnet: adhere to style

2025-11-14T01:47:38+00:00

This satisfies the coding style. Signed-off-by: Oliver Neukum Link: https://patch.msgid.link/20251112102610.281565-1-oneukum@suse.com Signed-off-by: Jakub Kicinski

usbnet: Add support for Byte Queue Limits (BQL)

2025-11-11T01:28:38+00:00

In the current implementation, usbnet uses a fixed tx_qlen of: USB2: 60 * 1518 bytes = 91.08 KB USB3: 60 * 5 * 1518 bytes = 454.80 KB Such large transmit queues can be problematic, especially for cellular modems. For example, with a typical celluar link speed of 10 Mbit/s, a fully occupied USB3 transmit queue results in: 454.80 KB / (10 Mbit/s / 8 bit/byte) = 363.84 ms of additional latency. This patch adds support for Byte Queue Limits (BQL) [1] to dynamically manage the transmit queue size and reduce latency without sacrificing throughput. Testing was performed on various devices using the usbnet driver for packet transmission: - DELOCK 66045: USB3 to 2.5 GbE adapter (ax88179_178a) - DELOCK 61969: USB2 to 1 GbE adapter (asix) - Quectel RM520: 5G modem (qmi_wwan) - USB2 Android tethering (cdc_ncm) No performance degradation was observed for iperf3 TCP or UDP traffic, while latency for a prioritized ping application was significantly reduced. For example, using the USB3 to 2.5 GbE adapter, which was fully utilized by iperf3 UDP traffic, the prioritized ping was improved from 1.6 ms to 0.6 ms. With the same setup but with a 100 Mbit/s Ethernet connection, the prioritized ping was improved from 35 ms to 5 ms. [1] https://lwn.net/Articles/469652/ Signed-off-by: Simon Schippers Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20251106175615.26948-1-simon.schippers@tu-dortmund.de Signed-off-by: Jakub Kicinski