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 --- include/sound/util_mem.h | 51 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 include/sound/util_mem.h (limited to 'include/sound/util_mem.h') diff --git a/include/sound/util_mem.h b/include/sound/util_mem.h new file mode 100644 index 000000000..01310e089 --- /dev/null +++ b/include/sound/util_mem.h @@ -0,0 +1,51 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef __SOUND_UTIL_MEM_H +#define __SOUND_UTIL_MEM_H + +#include +/* + * Copyright (C) 2000 Takashi Iwai + * + * Generic memory management routines for soundcard memory allocation + */ + +/* + * memory block + */ +struct snd_util_memblk { + unsigned int size; /* size of this block */ + unsigned int offset; /* zero-offset of this block */ + struct list_head list; /* link */ +}; + +#define snd_util_memblk_argptr(blk) (void*)((char*)(blk) + sizeof(struct snd_util_memblk)) + +/* + * memory management information + */ +struct snd_util_memhdr { + unsigned int size; /* size of whole data */ + struct list_head block; /* block linked-list header */ + int nblocks; /* # of allocated blocks */ + unsigned int used; /* used memory size */ + int block_extra_size; /* extra data size of chunk */ + struct mutex block_mutex; /* lock */ +}; + +/* + * prototypes + */ +struct snd_util_memhdr *snd_util_memhdr_new(int memsize); +void snd_util_memhdr_free(struct snd_util_memhdr *hdr); +struct snd_util_memblk *snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size); +int snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk); +int snd_util_mem_avail(struct snd_util_memhdr *hdr); + +/* functions without mutex */ +struct snd_util_memblk *__snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size); +void __snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk); +struct snd_util_memblk *__snd_util_memblk_new(struct snd_util_memhdr *hdr, + unsigned int units, + struct list_head *prev); + +#endif /* __SOUND_UTIL_MEM_H */ -- cgit v1.3.1