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 --- drivers/clk/sprd/div.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) create mode 100644 drivers/clk/sprd/div.c (limited to 'drivers/clk/sprd/div.c') diff --git a/drivers/clk/sprd/div.c b/drivers/clk/sprd/div.c new file mode 100644 index 000000000..cd57163a7 --- /dev/null +++ b/drivers/clk/sprd/div.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Spreadtrum divider clock driver +// +// Copyright (C) 2017 Spreadtrum, Inc. +// Author: Chunyan Zhang + +#include + +#include "div.h" + +static int sprd_div_determine_rate(struct clk_hw *hw, + struct clk_rate_request *req) +{ + struct sprd_div *cd = hw_to_sprd_div(hw); + + return divider_determine_rate(&cd->common.hw, req, NULL, cd->div.width, 0); +} + +unsigned long sprd_div_helper_recalc_rate(struct sprd_clk_common *common, + const struct sprd_div_internal *div, + unsigned long parent_rate) +{ + unsigned long val; + unsigned int reg; + + regmap_read(common->regmap, common->reg + div->offset, ®); + val = reg >> div->shift; + val &= (1 << div->width) - 1; + + return divider_recalc_rate(&common->hw, parent_rate, val, NULL, 0, + div->width); +} +EXPORT_SYMBOL_GPL(sprd_div_helper_recalc_rate); + +static unsigned long sprd_div_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct sprd_div *cd = hw_to_sprd_div(hw); + + return sprd_div_helper_recalc_rate(&cd->common, &cd->div, parent_rate); +} + +int sprd_div_helper_set_rate(const struct sprd_clk_common *common, + const struct sprd_div_internal *div, + unsigned long rate, + unsigned long parent_rate) +{ + unsigned long val; + unsigned int reg; + + val = divider_get_val(rate, parent_rate, NULL, + div->width, 0); + + regmap_read(common->regmap, common->reg + div->offset, ®); + reg &= ~GENMASK(div->width + div->shift - 1, div->shift); + + regmap_write(common->regmap, common->reg + div->offset, + reg | (val << div->shift)); + + return 0; + +} +EXPORT_SYMBOL_GPL(sprd_div_helper_set_rate); + +static int sprd_div_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct sprd_div *cd = hw_to_sprd_div(hw); + + return sprd_div_helper_set_rate(&cd->common, &cd->div, + rate, parent_rate); +} + +const struct clk_ops sprd_div_ops = { + .recalc_rate = sprd_div_recalc_rate, + .determine_rate = sprd_div_determine_rate, + .set_rate = sprd_div_set_rate, +}; +EXPORT_SYMBOL_GPL(sprd_div_ops); -- cgit v1.3.1