kernel/linux.git/drivers/net/tun.c, branch v7.2-rc1

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2026-06-11T21:33:35+00:00

Cross-merge networking fixes after downstream PR (net-7.1-rc8). Conflicts: drivers/net/ethernet/wangxun/txgbe/txgbe_aml.c f67aead16e85 ("net: txgbe: rework service event handling") 57d39faed4c9 ("net: txgbe: improve functions of AML 40G devices") net/rds/info.c 512db8267b73 ("rds: mark snapshot pages dirty in rds_info_getsockopt()") 6e94eeb2a2a6 ("rds: convert to getsockopt_iter") Adjacent changes: include/net/sock.h 1ee90b77b727 ("net: guard timestamp cmsgs to real error queue skbs") f0de88303d5e ("net: make is_skb_wmem() available to modules") Signed-off-by: Jakub Kicinski

tun: zero the whole vnet header in tun_put_user()

2026-06-10T01:33:18+00:00

tun_put_user() declares an on-stack struct virtio_net_hdr_v1_hash_tunnel without zeroing it. For a non-tunnel skb, virtio_net_hdr_tnl_from_skb() only initializes the first 10 bytes (sizeof(struct virtio_net_hdr)), leaving bytes 10..23 (num_buffers and the hash/tunnel fields) as stack garbage. An unprivileged user can set the vnet header size to 24 with TUNSETVNETHDRSZ, so __tun_vnet_hdr_put() copies all 24 bytes of the partially-initialized struct to userspace, leaking 14 bytes of kernel stack on every read of a non-tunnel packet. Fix it the same way tun_get_user() already does by zeroing the whole header right after declaration. Fixes: 288f30435132 ("tun: enable gso over UDP tunnel support.") Reported-by: Weiming Shi Signed-off-by: Xiang Mei Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260607054428.3050243-1-xmei5@asu.edu Signed-off-by: Jakub Kicinski

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2026-05-28T21:02:21+00:00

Cross-merge networking fixes after downstream PR (net-7.1-rc6). Conflicts: drivers/net/phy/air_en8811h.c d895767c33781 ("net: phy: air_en8811h: add AN8811HB MCU assert/deassert support") dddfadd75197e ("net: phy: Add Airoha phy library for shared code") 5226bb6634cdf ("net: phy: air_phy_lib: Factorize BuckPBus register accessors") e08f0ea6daf2e ("net: phy: Rename Airoha common BuckPBus register accessors") net/sched/sch_netem.c a2f6ed7b4873 ("net/sched: netem: add per-impairment extended statistics") 9552b11e3eda ("net/sched: fix packet loop on netem when duplicate is on") Adjacent changes: drivers/dpll/zl3073x/core.c c1224569cef0 ("dpll: zl3073x: make frequency monitor a per-device attribute") 54e65df8cf18 ("dpll: zl3073x: report FFO as DPLL vs input reference offset") net/iucv/af_iucv.c 347fdd4df85f ("af_iucv: convert to getsockopt_iter") 3589d20a666c ("net/iucv: fix locking in .getsockopt") Signed-off-by: Jakub Kicinski

tun: free page on build_skb failure in tun_xdp_one()

2026-05-22T17:10:07+00:00

When build_skb() fails in tun_xdp_one(), the function sets ret to -ENOMEM and jumps to the out label, which returns without freeing the page that vhost_net_build_xdp() allocated for the frame. As with the short-frame rejection path, tun_sendmsg() discards the per-buffer error and still returns total_len, so vhost_tx_batch() takes the success path and never frees the page. Each build_skb() failure in a batch leaks one page-frag chunk. Free the page before taking the error path, matching the put_page() the other error exits of tun_xdp_one() already perform. Fixes: 043d222f93ab ("tuntap: accept an array of XDP buffs through sendmsg()") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Reviewed-by: Dongli Zhang Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260521163312.1479805-2-bestswngs@gmail.com Signed-off-by: Jakub Kicinski

tun: free page on short-frame rejection in tun_xdp_one()

2026-05-22T14:56:27+00:00

tun_xdp_one() returns -EINVAL on a frame shorter than ETH_HLEN without freeing the page that vhost_net_build_xdp() allocated for it. tun_sendmsg() discards that -EINVAL and still returns total_len, so vhost_tx_batch() takes the success path and never frees the page; each short frame in a batch leaks one page-frag chunk. A local process that can open /dev/net/tun and /dev/vhost-net can hit this path: it attaches a tun/tap device as the vhost-net backend and feeds TX descriptors whose length minus the virtio-net header is below ETH_HLEN. Each kick leaks the page-frag chunks for that batch, and a tight submission loop exhausts host memory and triggers an OOM panic. Free the page before returning -EINVAL, matching the XDP-program error path in the same function. Fixes: 049584807f1d ("tun: add missing verification for short frame") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Reviewed-by: Dongli Zhang Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260520160020.375349-2-bestswngs@gmail.com Signed-off-by: Jakub Kicinski

tun/tap & vhost-net: avoid ptr_ring tail-drop when a qdisc is present

2026-05-14T00:52:55+00:00

This commit prevents tail-drop when a qdisc is present and the ptr_ring becomes full. Once the ring reaches capacity after a produce attempt, the netdev queue is stopped instead of dropping subsequent packets. If no qdisc is present, the previous tail-drop behavior is preserved. If producing an entry fails anyway due to a race, tun_net_xmit() drops the packet. Such races are expected because LLTX is enabled and the transmit path operates without the usual locking. The __tun_wake_queue() function of the consumer races with the producer for waking/stopping the netdev queue, which could result in a stalled queue. Therefore, an smp_mb__after_atomic() is introduced that pairs with the smp_mb() of the consumer. It follows the principle of store buffering described in tools/memory-model/Documentation/recipes.txt: - The producer in tun_net_xmit() first sets __QUEUE_STATE_DRV_XOFF, followed by an smp_mb__after_atomic() (= smp_mb()), and then reads the ring with __ptr_ring_check_produce(). - The consumer in __tun_wake_queue() first writes zero to the ring in __ptr_ring_consume(), followed by an smp_mb(), and then reads the queue status with netif_tx_queue_stopped(). => Following the aforementioned principle, it is impossible for the producer to see a full ring (and therefore not wake the queue on the re-check) while the consumer simultaneously fails to see a stopped queue (and therefore also does not wake it). Benchmarks: The benchmarks show a slight regression in raw transmission performance when using two sending threads. Packet loss also occurs only in the two-thread sending case; no packet loss was observed with a single sending thread. Test setup: AMD Ryzen 5 5600X at 4.3 GHz, 3200 MHz RAM, isolated QEMU threads; Average over 50 runs @ 100,000,000 packets. SRSO and spectre v2 mitigations disabled. Note for tap+vhost-net: XDP drop program active in VM -> ~2.5x faster; slower for tap due to more syscalls (high utilization of entry_SYSRETQ_unsafe_stack in perf) +--------------------------+--------------+----------------+----------+ | 1 thread | Stock | Patched with | diff | | sending | | fq_codel qdisc | | +------------+-------------+--------------+----------------+----------+ | TAP | Received | 1.132 Mpps | 1.123 Mpps | -0.8% | | +-------------+--------------+----------------+----------+ | | Lost/s | 3.765 Mpps | 0 pps | | +------------+-------------+--------------+----------------+----------+ | TAP | Received | 3.857 Mpps | 3.901 Mpps | +1.1% | | +-------------+--------------+----------------+----------+ | +vhost-net | Lost/s | 0.802 Mpps | 0 pps | | +------------+-------------+--------------+----------------+----------+ +--------------------------+--------------+----------------+----------+ | 2 threads | Stock | Patched with | diff | | sending | | fq_codel qdisc | | +------------+-------------+--------------+----------------+----------+ | TAP | Received | 1.115 Mpps | 1.081 Mpps | -3.0% | | +-------------+--------------+----------------+----------+ | | Lost/s | 8.490 Mpps | 391 pps | | +------------+-------------+--------------+----------------+----------+ | TAP | Received | 3.664 Mpps | 3.555 Mpps | -3.0% | | +-------------+--------------+----------------+----------+ | +vhost-net | Lost/s | 5.330 Mpps | 938 pps | | +------------+-------------+--------------+----------------+----------+ Co-developed-by: Tim Gebauer Signed-off-by: Tim Gebauer Signed-off-by: Simon Schippers Acked-by: Michael S. Tsirkin Link: https://patch.msgid.link/20260510151529.43895-5-simon.schippers@tu-dortmund.de Signed-off-by: Jakub Kicinski

vhost-net: wake queue of tun/tap after ptr_ring consume

2026-05-14T00:52:55+00:00

Add tun_wake_queue() to tun.c and export it for use by vhost-net. The function validates that the file belongs to a tun/tap device and that the tfile exists, dereferences the tun_struct under RCU, and delegates to __tun_wake_queue(). vhost_net_buf_produce() now calls tun_wake_queue() after a successful batched consume of the ring to allow the netdev subqueue to be woken up. The point is to allow the queue to be stopped when it gets full, which is required for traffic shaping - implemented by the following "avoid ptr_ring tail-drop when a qdisc is present". Without the corresponding queue stopping, this patch alone causes no throughput regression for a tap+vhost-net setup sending to a qemu VM: 3.857 Mpps to 3.891 Mpps. Details: AMD Ryzen 5 5600X at 4.3 GHz, 3200 MHz RAM, isolated QEMU threads, XDP drop program active in VM, pktgen sender; Avg over 50 runs @ 100,000,000 packets. SRSO and spectre v2 mitigations disabled. Co-developed-by: Tim Gebauer Signed-off-by: Tim Gebauer Signed-off-by: Simon Schippers Acked-by: Michael S. Tsirkin Link: https://patch.msgid.link/20260510151529.43895-3-simon.schippers@tu-dortmund.de Signed-off-by: Jakub Kicinski

tun/tap: add ptr_ring consume helper with netdev queue wakeup

2026-05-14T00:52:55+00:00

Introduce tun_ring_consume() that wraps ptr_ring_consume() and calls __tun_wake_queue(). The latter wakes the stopped netdev subqueue once half of the ring capacity has been consumed, tracked via the new cons_cnt field in tun_file. As a safety net, the queue is also woken on the last consumed entry if it leaves the ring empty. The point is to allow the queue to be stopped when it gets full, which is required for traffic shaping - implemented by the following "avoid ptr_ring tail-drop when a qdisc is present". Some implementation details: - tun_ring_recv() replaces ptr_ring_consume() with tun_ring_consume() to properly wake the queue. - __tun_detach() locks the tx_ring.consumer_lock to avoid races with the consumer on the queue_index. - The ptr_ring_consume() call in tun_queue_purge() is not replaced with tun_ring_consume(). Instead, within the same tx_ring.consumer_lock in __tun_detach(), the netdev queue is woken for the ntfile taking it over, to avoid a possible stall. This does not matter for tun_detach_all(), as it is called during device teardown and no tfile takes over any queue. - Reset cons_cnt in tun_attach() so the half-ring wake threshold is valid for the new ring size after ptr_ring_resize(). - tun_queue_resize() wakes all queues after resizing with the proper tx_ring.consumer_lock and resets the cons_cnt to avoid a possible stale queue. - The aforementioned upcoming patch explains the pairing of the smp_mb() of __tun_wake_queue(). Without the corresponding queue stopping, this patch alone causes no regression for a tap setup sending to a qemu VM: 1.132 Mpps to 1.134 Mpps. Details: AMD Ryzen 5 5600X at 4.3 GHz, 3200 MHz RAM, isolated QEMU threads, pktgen sender; Avg over 50 runs @ 100,000,000 packets; SRSO and spectre v2 mitigations disabled. Co-developed-by: Tim Gebauer Signed-off-by: Tim Gebauer Signed-off-by: Simon Schippers Acked-by: Michael S. Tsirkin Link: https://patch.msgid.link/20260510151529.43895-2-simon.schippers@tu-dortmund.de Signed-off-by: Jakub Kicinski

net: change sk_filter_reason() to return the reason by value

2026-04-12T21:30:25+00:00

sk_filter_trim_cap will soon return the reason by value, do the same for sk_filter_reason(). $ scripts/bloat-o-meter -t vmlinux.old vmlinux.new add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-21 (-21) Function old new delta sock_queue_rcv_skb_reason 128 126 -2 tun_net_xmit 1146 1127 -19 Total: Before=29722661, After=29722640, chg -0.00% Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260409145625.2306224-4-edumazet@google.com Signed-off-by: Jakub Kicinski

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\