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 --- fs/minix/itree_v2.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) create mode 100644 fs/minix/itree_v2.c (limited to 'fs/minix/itree_v2.c') diff --git a/fs/minix/itree_v2.c b/fs/minix/itree_v2.c new file mode 100644 index 000000000..9d00f31a2 --- /dev/null +++ b/fs/minix/itree_v2.c @@ -0,0 +1,75 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include "minix.h" + +enum {DIRECT = 7, DEPTH = 4}; /* Have triple indirect */ + +typedef u32 block_t; /* 32 bit, host order */ + +static inline unsigned long block_to_cpu(block_t n) +{ + return n; +} + +static inline block_t cpu_to_block(unsigned long n) +{ + return n; +} + +static inline block_t *i_data(struct inode *inode) +{ + return (block_t *)minix_i(inode)->u.i2_data; +} + +#define DIRCOUNT 7 +#define INDIRCOUNT(sb) (1 << ((sb)->s_blocksize_bits - 2)) + +static int block_to_path(struct inode * inode, long block, int offsets[DEPTH]) +{ + int n = 0; + struct super_block *sb = inode->i_sb; + + if (block < 0) { + printk("MINIX-fs: block_to_path: block %ld < 0 on dev %pg\n", + block, sb->s_bdev); + return 0; + } + if ((u64)block * (u64)sb->s_blocksize >= sb->s_maxbytes) + return 0; + + if (block < DIRCOUNT) { + offsets[n++] = block; + } else if ((block -= DIRCOUNT) < INDIRCOUNT(sb)) { + offsets[n++] = DIRCOUNT; + offsets[n++] = block; + } else if ((block -= INDIRCOUNT(sb)) < INDIRCOUNT(sb) * INDIRCOUNT(sb)) { + offsets[n++] = DIRCOUNT + 1; + offsets[n++] = block / INDIRCOUNT(sb); + offsets[n++] = block % INDIRCOUNT(sb); + } else { + block -= INDIRCOUNT(sb) * INDIRCOUNT(sb); + offsets[n++] = DIRCOUNT + 2; + offsets[n++] = (block / INDIRCOUNT(sb)) / INDIRCOUNT(sb); + offsets[n++] = (block / INDIRCOUNT(sb)) % INDIRCOUNT(sb); + offsets[n++] = block % INDIRCOUNT(sb); + } + return n; +} + +#include "itree_common.c" + +int V2_minix_get_block(struct inode * inode, long block, + struct buffer_head *bh_result, int create) +{ + return get_block(inode, block, bh_result, create); +} + +void V2_minix_truncate(struct inode * inode) +{ + truncate(inode); +} + +unsigned V2_minix_blocks(loff_t size, struct super_block *sb) +{ + return nblocks(size, sb); +} -- cgit v1.3.1