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 --- tools/lib/thermal/sampling.c | 77 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 tools/lib/thermal/sampling.c (limited to 'tools/lib/thermal/sampling.c') diff --git a/tools/lib/thermal/sampling.c b/tools/lib/thermal/sampling.c new file mode 100644 index 000000000..f67c1f9ea --- /dev/null +++ b/tools/lib/thermal/sampling.c @@ -0,0 +1,77 @@ +// SPDX-License-Identifier: LGPL-2.1+ +// Copyright (C) 2022, Linaro Ltd - Daniel Lezcano +#include +#include +#include +#include + +#include +#include "thermal_nl.h" + +static int handle_thermal_sample(struct nl_msg *n, void *arg) +{ + struct nlmsghdr *nlh = nlmsg_hdr(n); + struct genlmsghdr *genlhdr = genlmsg_hdr(nlh); + struct nlattr *attrs[THERMAL_GENL_ATTR_MAX + 1]; + struct thermal_handler_param *thp = arg; + struct thermal_handler *th = thp->th; + + arg = thp->arg; + + genlmsg_parse(nlh, 0, attrs, THERMAL_GENL_ATTR_MAX, NULL); + + switch (genlhdr->cmd) { + + case THERMAL_GENL_SAMPLING_TEMP: + return th->ops->sampling.tz_temp( + nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]), + nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TEMP]), arg); + default: + return THERMAL_ERROR; + } +} + +thermal_error_t thermal_sampling_handle(struct thermal_handler *th, void *arg) +{ + struct thermal_handler_param thp = { .th = th, .arg = arg }; + + if (!th) + return THERMAL_ERROR; + + if (nl_cb_set(th->cb_sampling, NL_CB_VALID, NL_CB_CUSTOM, + handle_thermal_sample, &thp)) + return THERMAL_ERROR; + + return nl_recvmsgs(th->sk_sampling, th->cb_sampling); +} + +int thermal_sampling_fd(struct thermal_handler *th) +{ + if (!th) + return -1; + + return nl_socket_get_fd(th->sk_sampling); +} + +thermal_error_t thermal_sampling_exit(struct thermal_handler *th) +{ + if (nl_unsubscribe_thermal(th->sk_sampling, th->cb_sampling, + THERMAL_GENL_SAMPLING_GROUP_NAME)) + return THERMAL_ERROR; + + nl_thermal_disconnect(th->sk_sampling, th->cb_sampling); + + return THERMAL_SUCCESS; +} + +thermal_error_t thermal_sampling_init(struct thermal_handler *th) +{ + if (nl_thermal_connect(&th->sk_sampling, &th->cb_sampling)) + return THERMAL_ERROR; + + if (nl_subscribe_thermal(th->sk_sampling, th->cb_sampling, + THERMAL_GENL_SAMPLING_GROUP_NAME)) + return THERMAL_ERROR; + + return THERMAL_SUCCESS; +} -- cgit v1.3.1