kernel/linux.git/net/sched, branch v6.18.33

net/sched: sch_pie: annotate more data-races in pie_dump_stats()

2026-05-23T11:07:14+00:00

[ Upstream commit 6d4106e8df94c0c52cf3ca6a6a0d01567fb3844e ] My prior patch missed few READ_ONCE()/WRITE_ONCE() annotations. Fixes: 5154561d9b11 ("net/sched: sch_pie: annotate data-races in pie_dump_stats()") Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260430080056.35104-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net/sched: cls_flower: revert unintended changes

2026-05-23T11:07:14+00:00

[ Upstream commit 1e01abec856593e02cd69fd95b784c10dd46880c ] While applying the blamed commit 4ca07b9239bd ("net: mctp i2c: check length before marking flow active"), I unintentionally included unrelated and unacceptable changes. Revert them. Fixes: 4ca07b9239bd ("net: mctp i2c: check length before marking flow active") Reported-by: Jeremy Kerr Closes: https://lore.kernel.org/netdev/bd8704fe0bd53e278add5cde4873256656623e2e.camel@codeconstruct.com.au/ Signed-off-by: Paolo Abeni Link: https://patch.msgid.link/043026a53ff84da88b17648c4b0d17f0331749cb.1777447863.git.pabeni@redhat.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net/sched: sch_cake: annotate data-races in cake_dump_stats() (V)

2026-05-23T11:07:12+00:00

[ Upstream commit a6c95b833dc17e84d16a8ac0f40fd0931616a52d ] cake_dump_stats() runs without qdisc spinlock being held. In this final patch, I add READ_ONCE()/WRITE_ONCE() annotations for cparams.target and cparams.interval. Fixes: 046f6fd5daef ("sched: Add Common Applications Kept Enhanced (cake) qdisc") Signed-off-by: Eric Dumazet Acked-by: "Toke Høiland-Jørgensen" Link: https://patch.msgid.link/20260427083606.459355-6-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net/sched: sch_cake: annotate data-races in cake_dump_stats() (III)

2026-05-23T11:07:11+00:00

[ Upstream commit 276a98a434964088fccd4745db5b34d6e831e358 ] cake_dump_stats() runs without qdisc spinlock being held. In this third patch, I add READ_ONCE()/WRITE_ONCE() annotations for the following fields: - packets - tin_dropped - tin_ecn_mark - ack_drops - peak_delay - avge_delay - base_delay Other annotations are added in following patches, to ease code review. Fixes: 046f6fd5daef ("sched: Add Common Applications Kept Enhanced (cake) qdisc") Signed-off-by: Eric Dumazet Acked-by: "Toke Høiland-Jørgensen" Link: https://patch.msgid.link/20260427083606.459355-4-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: mctp i2c: check length before marking flow active

2026-05-23T11:07:10+00:00

[ Upstream commit 4ca07b9239bd0478ae586632a2ed72be37ed8407 ] Currently, mctp_i2c_get_tx_flow_state() is called before the packet length sanity check. This function marks a new flow as active in the MCTP core. If the sanity check fails, mctp_i2c_xmit() returns early without calling mctp_i2c_lock_nest(). This results in a mismatched locking state: the flow is active, but the I2C bus lock was never acquired for it. When the flow is later released, mctp_i2c_release_flow() will see the active state and queue an unlock marker. The TX thread will then decrement midev->i2c_lock_count from 0, causing it to underflow to -1. This underflow permanently breaks the driver's locking logic, allowing future transmissions to occur without holding the I2C bus lock, leading to bus collisions and potential hardware hangs. Move the mctp_i2c_get_tx_flow_state() call to after the length sanity check to ensure we only transition the flow state if we are actually going to proceed with the transmission and locking. Fixes: f5b8abf9fc3d ("mctp i2c: MCTP I2C binding driver") Signed-off-by: William A. Kennington III Acked-by: Jeremy Kerr Link: https://patch.msgid.link/20260423074741.201460-1-william@wkennington.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net/sched: taprio: fix NULL pointer dereference in class dump

2026-05-23T11:07:09+00:00

[ Upstream commit 3d07ca5c0fae311226f737963984bd94bb159a87 ] When a TAPRIO child qdisc is deleted via RTM_DELQDISC, taprio_graft() is called with new == NULL and stores NULL into q->qdiscs[cl - 1]. Subsequent RTM_GETTCLASS dump operations walk all classes via taprio_walk() and call taprio_dump_class(), which calls taprio_leaf() returning the NULL pointer, then dereferences it to read child->handle, causing a kernel NULL pointer dereference. The bug is reachable with namespace-scoped CAP_NET_ADMIN on any kernel with CONFIG_NET_SCH_TAPRIO enabled. On systems with unprivileged user namespaces enabled, an unprivileged local user can trigger a kernel panic by creating a taprio qdisc inside a new network namespace, grafting an explicit child qdisc, deleting it, and requesting a class dump. The RTM_GETTCLASS dump itself requires no capability. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000007: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f] RIP: 0010:taprio_dump_class (net/sched/sch_taprio.c:2478) Call Trace: tc_fill_tclass (net/sched/sch_api.c:1966) qdisc_class_dump (net/sched/sch_api.c:2326) taprio_walk (net/sched/sch_taprio.c:2514) tc_dump_tclass_qdisc (net/sched/sch_api.c:2352) tc_dump_tclass_root (net/sched/sch_api.c:2370) tc_dump_tclass (net/sched/sch_api.c:2431) rtnl_dumpit (net/core/rtnetlink.c:6864) netlink_dump (net/netlink/af_netlink.c:2325) rtnetlink_rcv_msg (net/core/rtnetlink.c:6959) netlink_rcv_skb (net/netlink/af_netlink.c:2550) Fix this by substituting &noop_qdisc when new is NULL in taprio_graft(), a common pattern used by other qdiscs (e.g., multiq_graft()) to ensure the q->qdiscs[] slots are never NULL. This makes control-plane dump paths safe without requiring individual NULL checks. Since the data-plane paths (taprio_enqueue and taprio_dequeue_from_txq) previously had explicit NULL guards that would drop/skip the packet cleanly, update those checks to test for &noop_qdisc instead. Without this, packets would reach taprio_enqueue_one() which increments the root qdisc's qlen and backlog before calling the child's enqueue; noop_qdisc drops the packet but those counters are never rolled back, permanently inflating the root qdisc's statistics. After this change *old can be a valid qdisc, NULL, or &noop_qdisc. Only call qdisc_put(*old) in the first case to avoid decreasing noop_qdisc's refcount, which was never increased. Fixes: 665338b2a7a0 ("net/sched: taprio: dump class stats for the actual q->qdiscs[]") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Acked-by: Jamal Hadi Salim Tested-by: Weiming Shi Link: https://patch.msgid.link/20260422161958.2517539-3-bestswngs@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net/sched: sch_fq_pie: annotate data-races in fq_pie_dump_stats()

2026-05-23T11:07:09+00:00

[ Upstream commit 59b145771c7982cfe9020d4e9e22da92d6b5ae31 ] fq_codel_dump_stats() acquires the qdisc spinlock a bit too late. Move this acquisition before we fill tc_fq_pie_xstats with live data. Alternative would be to add READ_ONCE() and WRITE_ONCE() annotations, but the spinlock is needed anyway to scan q->new_flows and q->old_flows. Fixes: ec97ecf1ebe4 ("net: sched: add Flow Queue PIE packet scheduler") Signed-off-by: Eric Dumazet Reviewed-by: Jamal Hadi Salim Link: https://patch.msgid.link/20260423063527.2568262-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net/sched: sch_choke: annotate data-races in choke_dump_stats()

2026-05-23T11:07:09+00:00

[ Upstream commit d3aeb889dcbd78e95f500d383799a23d949796e0 ] choke_dump_stats() only runs with RTNL held. It reads fields that can be changed in qdisc fast path. Add READ_ONCE()/WRITE_ONCE() annotations. Fixes: edb09eb17ed8 ("net: sched: do not acquire qdisc spinlock in qdisc/class stats dump") Signed-off-by: Eric Dumazet Reviewed-by: Jamal Hadi Salim Link: https://patch.msgid.link/20260423062839.2524324-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net/sched: netem: check for negative latency and jitter

2026-05-23T11:07:08+00:00

[ Upstream commit 90be9fedb218ee95a1cf59050d1306fbfb0e8b87 ] Reject requests with negative latency or jitter. A negative value added to current timestamp (u64) wraps to an enormous time_to_send, disabling dequeue. The original UAPI used u32 for these values; the conversion to 64-bit time values via TCA_NETEM_LATENCY64 and TCA_NETEM_JITTER64 allowed signed values to reach the kernel without validation. Jitter is already silently clamped by an abs() in netem_change(); that abs() can be removed in a follow-up once this rejection is in place. Fixes: 99803171ef04 ("netem: add uapi to express delay and jitter in nanoseconds") Signed-off-by: Stephen Hemminger Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260418032027.900913-7-stephen@networkplumber.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net/sched: netem: fix slot delay calculation overflow

2026-05-23T11:07:08+00:00

[ Upstream commit 51e94e1e2fef351c74d69eb53666df808d26af95 ] get_slot_next() computes a random delay between min_delay and max_delay using: get_random_u32() * (max_delay - min_delay) >> 32 This overflows signed 64-bit arithmetic when the delay range exceeds approximately 2.1 seconds (2^31 nanoseconds), producing a negative result that effectively disables slot-based pacing. This is a realistic configuration for WAN emulation (e.g., slot 1s 5s). Use mul_u64_u32_shr() which handles the widening multiply without overflow. Fixes: 0a9fe5c375b5 ("netem: slotting with non-uniform distribution") Signed-off-by: Stephen Hemminger Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260418032027.900913-6-stephen@networkplumber.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin