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 --- arch/powerpc/boot/swab.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 arch/powerpc/boot/swab.h (limited to 'arch/powerpc/boot/swab.h') diff --git a/arch/powerpc/boot/swab.h b/arch/powerpc/boot/swab.h new file mode 100644 index 000000000..11d2069fb --- /dev/null +++ b/arch/powerpc/boot/swab.h @@ -0,0 +1,30 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _PPC_BOOT_SWAB_H_ +#define _PPC_BOOT_SWAB_H_ + +static inline u16 swab16(u16 x) +{ + return ((x & (u16)0x00ffU) << 8) | + ((x & (u16)0xff00U) >> 8); +} + +static inline u32 swab32(u32 x) +{ + return ((x & (u32)0x000000ffUL) << 24) | + ((x & (u32)0x0000ff00UL) << 8) | + ((x & (u32)0x00ff0000UL) >> 8) | + ((x & (u32)0xff000000UL) >> 24); +} + +static inline u64 swab64(u64 x) +{ + return (u64)((x & (u64)0x00000000000000ffULL) << 56) | + (u64)((x & (u64)0x000000000000ff00ULL) << 40) | + (u64)((x & (u64)0x0000000000ff0000ULL) << 24) | + (u64)((x & (u64)0x00000000ff000000ULL) << 8) | + (u64)((x & (u64)0x000000ff00000000ULL) >> 8) | + (u64)((x & (u64)0x0000ff0000000000ULL) >> 24) | + (u64)((x & (u64)0x00ff000000000000ULL) >> 40) | + (u64)((x & (u64)0xff00000000000000ULL) >> 56); +} +#endif /* _PPC_BOOT_SWAB_H_ */ -- cgit v1.3.1