linux.git/net/sched/sch_sfq.c, branch master

net/sched: Handle TC_ACT_REDIRECT from qdisc filter chains

2026-07-21T01:16:43Z

When a TC filter attached to a qdisc filter chain returns TC_ACT_REDIRECT (ex: via an eBPF program calling bpf_redirect() or an act_bpf action), the redirect was silently lost i.e no qdisc classify function handled TC_ACT_REDIRECT, so the packet fell through the switch and was enqueued normally instead of being redirected. This has been broken since bpf_redirect() was introduced for TC in commit 27b29f63058d ("bpf: add bpf_redirect() helper"). We got lucky for a long time because bpf_net_context was a per-CPU variable that was always available. commit 401cb7dae813 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.") turned bpf_net_context into a task_struct member that is only set up by explicit callers. Without a caller setting it up, bpf_redirect() itself crashes with a NULL pointer dereference in bpf_net_ctx_get_ri(). However, even with bpf_net_context available, TC_ACT_REDIRECT from qdisc filter chains cannot be honored without adding skb_do_redirect() calls to every qdisc classify function, which would require changes across net/sched/. Isolate it to ebpf core where it belongs. Instead, add a tcf_classify_qdisc() inline helper in pkt_cls.h, as a wrapper around tcf_classify() for use by qdisc classify functions and tcf_qevent_handle(). When the classify verdict is TC_ACT_REDIRECT, the wrapper converts it to TC_ACT_SHOT, dropping the packet rather than letting it continue silently. Dropping is preferred over letting the packet through because the user immediately sees packet loss. Silently passing the packet through would hide the problem and leave the user wondering why their redirect is not working. The clsact fast path, tc_run() continues to call tcf_classify() directly and is unaffected: TC_ACT_REDIRECT is returned as-is and handled by sch_handle_egress/ingress() calling skb_do_redirect() as before. Fixes: 27b29f63058d ("bpf: add bpf_redirect() helper") Fixes: 401cb7dae813 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.") Tested-by: Victor Nogueira Signed-off-by: Jamal Hadi Salim Signed-off-by: Daniel Borkmann Reviewed-by: Sebastian Andrzej Siewior Link: https://patch.msgid.link/20260706185609.330006-3-daniel@iogearbox.net Signed-off-by: Jakub Kicinski

net/sched: annotate data-races around sch->qstats.backlog

2026-05-12T01:28:07Z

Add qstats_backlog_sub() and qstats_backlog_add() helpers and use them instead of open-coding them. These helpers use WRITE_ONCE() to prevent store-tearing. Also use WRITE_ONCE() in fq_reset() and qdisc_reset() when sch->qstats.backlog is cleared. Signed-off-by: Eric Dumazet Acked-by: Toke Høiland-Jørgensen Link: https://patch.msgid.link/20260510091455.4039245-4-edumazet@google.com Signed-off-by: Jakub Kicinski

net/sched: add qdisc_qlen_inc() and qdisc_qlen_dec()

2026-05-12T01:28:07Z

Helpers to increment or decrement sch->q.qlen, with appropriate WRITE_ONCE() to prevent store tearing. Add other WRITE_ONCE() when sch->q.qlen is changed. Signed-off-by: Eric Dumazet Acked-by: Toke Høiland-Jørgensen Link: https://patch.msgid.link/20260510091455.4039245-3-edumazet@google.com Signed-off-by: Jakub Kicinski

net/sched: sch_sfq: annotate data-races from sfq_dump_class_stats()

2026-05-07T00:46:05Z

sfq_dump_class_stats() runs locklessly, add needed READ_ONCE() and WRITE_ONCE() annotations. Fixes: edb09eb17ed8 ("net: sched: do not acquire qdisc spinlock in qdisc/class stats dump") Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260505091133.2452510-1-edumazet@google.com Signed-off-by: Jakub Kicinski

net: sched: sfq: convert to qdisc drop reasons

2026-02-28T23:31:34Z

Convert SFQ to use the new qdisc-specific drop reason infrastructure. This patch demonstrates how to convert a flow-based qdisc to use the new enum qdisc_drop_reason. As part of this conversion: - Add QDISC_DROP_MAXFLOWS for flow table exhaustion - Rename FQ_FLOW_LIMIT to generic FLOW_LIMIT, now shared by FQ and SFQ - Use QDISC_DROP_OVERLIMIT for sfq_drop() when overall limit exceeded - Use QDISC_DROP_FLOW_LIMIT for per-flow depth limit exceeded The FLOW_LIMIT reason is now a common drop reason for per-flow limits, applicable to both FQ and SFQ qdiscs. Signed-off-by: Jesper Dangaard Brouer Reviewed-by: Toke Høiland-Jørgensen Link: https://patch.msgid.link/177211345946.3011628.12770616071857185664.stgit@firesoul Signed-off-by: Jakub Kicinski

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

2026-02-22T01:09:51Z

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

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28Z

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 'net-6.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2025-06-12T16:50:36Z

Pull networking fixes from Jakub Kicinski: "Including fixes from bluetooth and wireless. Current release - regressions: - af_unix: allow passing cred for embryo without SO_PASSCRED/SO_PASSPIDFD Current release - new code bugs: - eth: airoha: correct enable mask for RX queues 16-31 - veth: prevent NULL pointer dereference in veth_xdp_rcv when peer disappears under traffic - ipv6: move fib6_config_validate() to ip6_route_add(), prevent invalid routes Previous releases - regressions: - phy: phy_caps: don't skip better duplex match on non-exact match - dsa: b53: fix untagged traffic sent via cpu tagged with VID 0 - Revert "wifi: mwifiex: Fix HT40 bandwidth issue.", it caused transient packet loss, exact reason not fully understood, yet Previous releases - always broken: - net: clear the dst when BPF is changing skb protocol (IPv4 <> IPv6) - sched: sfq: fix a potential crash on gso_skb handling - Bluetooth: intel: improve rx buffer posting to avoid causing issues in the firmware - eth: intel: i40e: make reset handling robust against multiple requests - eth: mlx5: ensure FW pages are always allocated on the local NUMA node, even when device is configure to 'serve' another node - wifi: ath12k: fix GCC_GCC_PCIE_HOT_RST definition for WCN7850, prevent kernel crashes - wifi: ath11k: avoid burning CPU in ath11k_debugfs_fw_stats_request() for 3 sec if fw_stats_done is not set" * tag 'net-6.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (70 commits) selftests: drv-net: rss_ctx: Add test for ntuple rules targeting default RSS context net: ethtool: Don't check if RSS context exists in case of context 0 af_unix: Allow passing cred for embryo without SO_PASSCRED/SO_PASSPIDFD. ipv6: Move fib6_config_validate() to ip6_route_add(). net: drv: netdevsim: don't napi_complete() from netpoll net/mlx5: HWS, Add error checking to hws_bwc_rule_complex_hash_node_get() veth: prevent NULL pointer dereference in veth_xdp_rcv net_sched: remove qdisc_tree_flush_backlog() net_sched: ets: fix a race in ets_qdisc_change() net_sched: tbf: fix a race in tbf_change() net_sched: red: fix a race in __red_change() net_sched: prio: fix a race in prio_tune() net_sched: sch_sfq: reject invalid perturb period net: phy: phy_caps: Don't skip better duplex macth on non-exact match MAINTAINERS: Update Kuniyuki Iwashima's email address. selftests: net: add test case for NAT46 looping back dst net: clear the dst when changing skb protocol net/mlx5e: Fix number of lanes to UNKNOWN when using data_rate_oper net/mlx5e: Fix leak of Geneve TLV option object net/mlx5: HWS, make sure the uplink is the last destination ...

net_sched: sch_sfq: reject invalid perturb period

2025-06-12T15:03:08Z

Gerrard Tai reported that SFQ perturb_period has no range check yet, and this can be used to trigger a race condition fixed in a separate patch. We want to make sure ctl->perturb_period * HZ will not overflow and is positive. Tested: tc qd add dev lo root sfq perturb -10 # negative value : error Error: sch_sfq: invalid perturb period. tc qd add dev lo root sfq perturb 1000000000 # too big : error Error: sch_sfq: invalid perturb period. tc qd add dev lo root sfq perturb 2000000 # acceptable value tc -s -d qd sh dev lo qdisc sfq 8005: root refcnt 2 limit 127p quantum 64Kb depth 127 flows 128 divisor 1024 perturb 2000000sec Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Gerrard Tai Signed-off-by: Eric Dumazet Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20250611083501.1810459-1-edumazet@google.com Signed-off-by: Jakub Kicinski

net_sched: sch_sfq: fix a potential crash on gso_skb handling

2025-06-09T21:21:36Z

SFQ has an assumption of always being able to queue at least one packet. However, after the blamed commit, sch->q.len can be inflated by packets in sch->gso_skb, and an enqueue() on an empty SFQ qdisc can be followed by an immediate drop. Fix sfq_drop() to properly clear q->tail in this situation. Tested: ip netns add lb ip link add dev to-lb type veth peer name in-lb netns lb ethtool -K to-lb tso off # force qdisc to requeue gso_skb ip netns exec lb ethtool -K in-lb gro on # enable NAPI ip link set dev to-lb up ip -netns lb link set dev in-lb up ip addr add dev to-lb 192.168.20.1/24 ip -netns lb addr add dev in-lb 192.168.20.2/24 tc qdisc replace dev to-lb root sfq limit 100 ip netns exec lb netserver netperf -H 192.168.20.2 -l 100 & netperf -H 192.168.20.2 -l 100 & netperf -H 192.168.20.2 -l 100 & netperf -H 192.168.20.2 -l 100 & Fixes: a53851e2c321 ("net: sched: explicit locking in gso_cpu fallback") Reported-by: Marcus Wichelmann Closes: https://lore.kernel.org/netdev/9da42688-bfaa-4364-8797-e9271f3bdaef@hetzner-cloud.de/ Signed-off-by: Eric Dumazet Reviewed-by: Toke Høiland-Jørgensen Link: https://patch.msgid.link/20250606165127.3629486-1-edumazet@google.com Signed-off-by: Jakub Kicinski