From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- lib/dim/dim.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 88 insertions(+) create mode 100644 lib/dim/dim.c (limited to 'lib/dim/dim.c') diff --git a/lib/dim/dim.c b/lib/dim/dim.c new file mode 100644 index 000000000..97c3d084e --- /dev/null +++ b/lib/dim/dim.c @@ -0,0 +1,88 @@ +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB +/* + * Copyright (c) 2019, Mellanox Technologies inc. All rights reserved. + */ + +#include + +bool dim_on_top(struct dim *dim) +{ + switch (dim->tune_state) { + case DIM_PARKING_ON_TOP: + case DIM_PARKING_TIRED: + return true; + case DIM_GOING_RIGHT: + return (dim->steps_left > 1) && (dim->steps_right == 1); + default: /* DIM_GOING_LEFT */ + return (dim->steps_right > 1) && (dim->steps_left == 1); + } +} +EXPORT_SYMBOL(dim_on_top); + +void dim_turn(struct dim *dim) +{ + switch (dim->tune_state) { + case DIM_PARKING_ON_TOP: + case DIM_PARKING_TIRED: + break; + case DIM_GOING_RIGHT: + dim->tune_state = DIM_GOING_LEFT; + dim->steps_left = 0; + break; + case DIM_GOING_LEFT: + dim->tune_state = DIM_GOING_RIGHT; + dim->steps_right = 0; + break; + } +} +EXPORT_SYMBOL(dim_turn); + +void dim_park_on_top(struct dim *dim) +{ + dim->steps_right = 0; + dim->steps_left = 0; + dim->tired = 0; + dim->tune_state = DIM_PARKING_ON_TOP; +} +EXPORT_SYMBOL(dim_park_on_top); + +void dim_park_tired(struct dim *dim) +{ + dim->steps_right = 0; + dim->steps_left = 0; + dim->tune_state = DIM_PARKING_TIRED; +} +EXPORT_SYMBOL(dim_park_tired); + +bool dim_calc_stats(const struct dim_sample *start, + const struct dim_sample *end, + struct dim_stats *curr_stats) +{ + /* u32 holds up to 71 minutes, should be enough */ + u32 delta_us = ktime_us_delta(end->time, start->time); + u32 npkts = BIT_GAP(BITS_PER_TYPE(u32), end->pkt_ctr, start->pkt_ctr); + u32 nbytes = BIT_GAP(BITS_PER_TYPE(u32), end->byte_ctr, + start->byte_ctr); + u32 ncomps = BIT_GAP(BITS_PER_TYPE(u32), end->comp_ctr, + start->comp_ctr); + + if (!delta_us) + return false; + + curr_stats->ppms = DIV_ROUND_UP(npkts * USEC_PER_MSEC, delta_us); + curr_stats->bpms = DIV_ROUND_UP(nbytes * USEC_PER_MSEC, delta_us); + curr_stats->epms = DIV_ROUND_UP(DIM_NEVENTS * USEC_PER_MSEC, + delta_us); + curr_stats->cpms = DIV_ROUND_UP(ncomps * USEC_PER_MSEC, delta_us); + if (curr_stats->epms != 0) + curr_stats->cpe_ratio = DIV_ROUND_DOWN_ULL( + curr_stats->cpms * 100, curr_stats->epms); + else + curr_stats->cpe_ratio = 0; + + return true; +} +EXPORT_SYMBOL(dim_calc_stats); + +MODULE_DESCRIPTION("Dynamic Interrupt Moderation (DIM) library"); +MODULE_LICENSE("Dual BSD/GPL"); -- cgit v1.3.1