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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/arm/mm/cache-nop.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/arm/mm/cache-nop.S')
| -rw-r--r-- | arch/arm/mm/cache-nop.S | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/arch/arm/mm/cache-nop.S b/arch/arm/mm/cache-nop.S new file mode 100644 index 000000000..f68dde201 --- /dev/null +++ b/arch/arm/mm/cache-nop.S @@ -0,0 +1,52 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#include <linux/linkage.h> +#include <linux/init.h> +#include <linux/cfi_types.h> +#include <asm/assembler.h> + +#include "proc-macros.S" + +/* + * These are all open-coded instead of aliased, to make clear + * what is going on here: all functions are stubbed out. + */ +SYM_TYPED_FUNC_START(nop_flush_icache_all) + ret lr +SYM_FUNC_END(nop_flush_icache_all) + +SYM_TYPED_FUNC_START(nop_flush_kern_cache_all) + ret lr +SYM_FUNC_END(nop_flush_kern_cache_all) + +SYM_TYPED_FUNC_START(nop_flush_user_cache_all) + ret lr +SYM_FUNC_END(nop_flush_user_cache_all) + +SYM_TYPED_FUNC_START(nop_flush_user_cache_range) + ret lr +SYM_FUNC_END(nop_flush_user_cache_range) + +SYM_TYPED_FUNC_START(nop_coherent_kern_range) + ret lr +SYM_FUNC_END(nop_coherent_kern_range) + +SYM_TYPED_FUNC_START(nop_coherent_user_range) + mov r0, 0 + ret lr +SYM_FUNC_END(nop_coherent_user_range) + +SYM_TYPED_FUNC_START(nop_flush_kern_dcache_area) + ret lr +SYM_FUNC_END(nop_flush_kern_dcache_area) + +SYM_TYPED_FUNC_START(nop_dma_flush_range) + ret lr +SYM_FUNC_END(nop_dma_flush_range) + +SYM_TYPED_FUNC_START(nop_dma_map_area) + ret lr +SYM_FUNC_END(nop_dma_map_area) + +SYM_TYPED_FUNC_START(nop_dma_unmap_area) + ret lr +SYM_FUNC_END(nop_dma_unmap_area) |