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 --- sound/soc/sof/sof-utils.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 sound/soc/sof/sof-utils.c (limited to 'sound/soc/sof/sof-utils.c') diff --git a/sound/soc/sof/sof-utils.c b/sound/soc/sof/sof-utils.c new file mode 100644 index 000000000..f70089317 --- /dev/null +++ b/sound/soc/sof/sof-utils.c @@ -0,0 +1,76 @@ +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) +// +// This file is provided under a dual BSD/GPLv2 license. When using or +// redistributing this file, you may do so under either license. +// +// Copyright(c) 2018-2022 Intel Corporation +// +// Author: Keyon Jie +// + +#include +#include +#include +#include +#include +#include "sof-utils.h" + +/* + * Generic buffer page table creation. + * Take the each physical page address and drop the least significant unused + * bits from each (based on PAGE_SIZE). Then pack valid page address bits + * into compressed page table. + */ + +int snd_sof_create_page_table(struct device *dev, + struct snd_dma_buffer *dmab, + unsigned char *page_table, size_t size) +{ + int i, pages; + + pages = snd_sgbuf_aligned_pages(size); + + dev_dbg(dev, "generating page table for %p size 0x%zx pages %d\n", + dmab->area, size, pages); + + for (i = 0; i < pages; i++) { + /* + * The number of valid address bits for each page is 20. + * idx determines the byte position within page_table + * where the current page's address is stored + * in the compressed page_table. + * This can be calculated by multiplying the page number by 2.5. + */ + u32 idx = (5 * i) >> 1; + u32 pfn = snd_sgbuf_get_addr(dmab, i * PAGE_SIZE) >> PAGE_SHIFT; + u8 *pg_table; + + pg_table = (u8 *)(page_table + idx); + + /* + * pagetable compression: + * byte 0 byte 1 byte 2 byte 3 byte 4 byte 5 + * ___________pfn 0__________ __________pfn 1___________ _pfn 2... + * .... .... .... .... .... .... .... .... .... .... .... + * It is created by: + * 1. set current location to 0, PFN index i to 0 + * 2. put pfn[i] at current location in Little Endian byte order + * 3. calculate an intermediate value as + * x = (pfn[i+1] << 4) | (pfn[i] & 0xf) + * 4. put x at offset (current location + 2) in LE byte order + * 5. increment current location by 5 bytes, increment i by 2 + * 6. continue to (2) + */ + if (i & 1) + put_unaligned_le32((pg_table[0] & 0xf) | pfn << 4, + pg_table); + else + put_unaligned_le32(pfn, pg_table); + } + + return pages; +} +EXPORT_SYMBOL(snd_sof_create_page_table); + +MODULE_LICENSE("Dual BSD/GPL"); +MODULE_DESCRIPTION("SOF utils"); -- cgit v1.3.1