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| author | Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2026-09-04 10:43:19 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-09-04 07:58:36 -0700 |
| commit | 6668ed271eaefaa63e686bdfbedaeb7b8e492722 (patch) | |
| tree | 58e8288fead484f6755ad0815fc74c3742663761 /arch/mips/mm/tlb-funcs.S | |
| download | linux-stable-6668ed271eaefaa63e686bdfbedaeb7b8e492722.tar.gz linux-stable-6668ed271eaefaa63e686bdfbedaeb7b8e492722.zip | |
selftests/bpf: Reject graph kptr use after RCU unlockgrafted
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 <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'arch/mips/mm/tlb-funcs.S')
| -rw-r--r-- | arch/mips/mm/tlb-funcs.S | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/arch/mips/mm/tlb-funcs.S b/arch/mips/mm/tlb-funcs.S new file mode 100644 index 000000000..2705d7dcb --- /dev/null +++ b/arch/mips/mm/tlb-funcs.S @@ -0,0 +1,40 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Micro-assembler generated tlb handler functions. + * + * Copyright (C) 2013 Broadcom Corporation. + * + * Based on mm/page-funcs.c + * Copyright (C) 2012 MIPS Technologies, Inc. + * Copyright (C) 2012 Ralf Baechle <ralf@linux-mips.org> + */ +#include <linux/export.h> +#include <asm/asm.h> +#include <asm/regdef.h> + +#define FASTPATH_SIZE 128 + +LEAF(tlbmiss_handler_setup_pgd) +1: j 1b /* Dummy, will be replaced. */ + .space 64 +END(tlbmiss_handler_setup_pgd) +EXPORT(tlbmiss_handler_setup_pgd_end) +EXPORT_SYMBOL_GPL(tlbmiss_handler_setup_pgd) + +LEAF(handle_tlbm) + .space FASTPATH_SIZE * 4 +END(handle_tlbm) +EXPORT(handle_tlbm_end) + +LEAF(handle_tlbs) + .space FASTPATH_SIZE * 4 +END(handle_tlbs) +EXPORT(handle_tlbs_end) + +LEAF(handle_tlbl) + .space FASTPATH_SIZE * 4 +END(handle_tlbl) +EXPORT(handle_tlbl_end) |