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/md/dm-vdo/permassert.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 drivers/md/dm-vdo/permassert.c (limited to 'drivers/md/dm-vdo/permassert.c') diff --git a/drivers/md/dm-vdo/permassert.c b/drivers/md/dm-vdo/permassert.c new file mode 100644 index 000000000..bf9eccea1 --- /dev/null +++ b/drivers/md/dm-vdo/permassert.c @@ -0,0 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2023 Red Hat + */ + +#include "permassert.h" + +#include "errors.h" +#include "logger.h" + +int vdo_assertion_failed(const char *expression_string, const char *file_name, + int line_number, const char *format, ...) +{ + va_list args; + + va_start(args, format); + + vdo_log_embedded_message(VDO_LOG_ERR, VDO_LOGGING_MODULE_NAME, "assertion \"", + format, args, "\" (%s) failed at %s:%d", + expression_string, file_name, line_number); + vdo_log_backtrace(VDO_LOG_ERR); + + va_end(args); + + return UDS_ASSERTION_FAILED; +} -- cgit v1.3.1