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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/lib/muldi3.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/lib/muldi3.S')
| -rw-r--r-- | arch/arm/lib/muldi3.S | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/arch/arm/lib/muldi3.S b/arch/arm/lib/muldi3.S new file mode 100644 index 000000000..8362fe6c0 --- /dev/null +++ b/arch/arm/lib/muldi3.S @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * linux/arch/arm/lib/muldi3.S + * + * Author: Nicolas Pitre + * Created: Oct 19, 2005 + * Copyright: Monta Vista Software, Inc. + */ + +#include <linux/linkage.h> +#include <asm/assembler.h> + +#ifdef __ARMEB__ +#define xh r0 +#define xl r1 +#define yh r2 +#define yl r3 +#else +#define xl r0 +#define xh r1 +#define yl r2 +#define yh r3 +#endif + +ENTRY(__muldi3) +ENTRY(__aeabi_lmul) + + mul xh, yl, xh + mla xh, xl, yh, xh + mov ip, xl, lsr #16 + mov yh, yl, lsr #16 + bic xl, xl, ip, lsl #16 + bic yl, yl, yh, lsl #16 + mla xh, yh, ip, xh + mul yh, xl, yh + mul xl, yl, xl + mul ip, yl, ip + adds xl, xl, yh, lsl #16 + adc xh, xh, yh, lsr #16 + adds xl, xl, ip, lsl #16 + adc xh, xh, ip, lsr #16 + ret lr + +ENDPROC(__muldi3) +ENDPROC(__aeabi_lmul) |