From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- fs/minix/bitmap.c | 269 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 269 insertions(+) create mode 100644 fs/minix/bitmap.c (limited to 'fs/minix/bitmap.c') diff --git a/fs/minix/bitmap.c b/fs/minix/bitmap.c new file mode 100644 index 000000000..abec43833 --- /dev/null +++ b/fs/minix/bitmap.c @@ -0,0 +1,269 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/minix/bitmap.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +/* + * Modified for 680x0 by Hamish Macdonald + * Fixed for 680x0 by Andreas Schwab + */ + +/* bitmap.c contains the code that handles the inode and block bitmaps */ + +#include "minix.h" +#include +#include +#include + +static DEFINE_SPINLOCK(bitmap_lock); + +/* + * bitmap consists of blocks filled with 16bit words + * bit set == busy, bit clear == free + * endianness is a mess, but for counting zero bits it really doesn't matter... + */ +static __u32 count_free(struct buffer_head *map[], unsigned blocksize, __u32 numbits) +{ + __u32 sum = 0; + unsigned blocks = DIV_ROUND_UP(numbits, blocksize * 8); + + while (blocks--) { + unsigned words = blocksize / 2; + __u16 *p = (__u16 *)(*map++)->b_data; + while (words--) + sum += 16 - hweight16(*p++); + } + + return sum; +} + +void minix_free_block(struct inode *inode, unsigned long block) +{ + struct super_block *sb = inode->i_sb; + struct minix_sb_info *sbi = minix_sb(sb); + struct buffer_head *bh; + int k = sb->s_blocksize_bits + 3; + unsigned long bit, zone; + + if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) { + printk("Trying to free block not in datazone\n"); + return; + } + zone = block - sbi->s_firstdatazone + 1; + bit = zone & ((1<>= k; + if (zone >= sbi->s_zmap_blocks) { + printk("minix_free_block: nonexistent bitmap buffer\n"); + return; + } + bh = sbi->s_zmap[zone]; + spin_lock(&bitmap_lock); + if (!minix_test_and_clear_bit(bit, bh->b_data)) + printk("minix_free_block (%s:%lu): bit already cleared\n", + sb->s_id, block); + spin_unlock(&bitmap_lock); + mark_buffer_dirty(bh); + return; +} + +int minix_new_block(struct inode * inode) +{ + struct minix_sb_info *sbi = minix_sb(inode->i_sb); + int bits_per_zone = 8 * inode->i_sb->s_blocksize; + int i; + + for (i = 0; i < sbi->s_zmap_blocks; i++) { + struct buffer_head *bh = sbi->s_zmap[i]; + int j; + + spin_lock(&bitmap_lock); + j = minix_find_first_zero_bit(bh->b_data, bits_per_zone); + if (j < bits_per_zone) { + minix_set_bit(j, bh->b_data); + spin_unlock(&bitmap_lock); + mark_buffer_dirty(bh); + j += i * bits_per_zone + sbi->s_firstdatazone-1; + if (j < sbi->s_firstdatazone || j >= sbi->s_nzones) + break; + return j; + } + spin_unlock(&bitmap_lock); + } + return 0; +} + +unsigned long minix_count_free_blocks(struct super_block *sb) +{ + struct minix_sb_info *sbi = minix_sb(sb); + u32 bits = sbi->s_nzones - sbi->s_firstdatazone + 1; + + return (count_free(sbi->s_zmap, sb->s_blocksize, bits) + << sbi->s_log_zone_size); +} + +struct minix_inode * +minix_V1_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh) +{ + int block; + struct minix_sb_info *sbi = minix_sb(sb); + struct minix_inode *p; + + if (!ino || ino > sbi->s_ninodes) { + printk("Bad inode number on dev %s: %ld is out of range\n", + sb->s_id, (long)ino); + return NULL; + } + ino--; + block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks + + ino / MINIX_INODES_PER_BLOCK; + *bh = sb_bread(sb, block); + if (!*bh) { + printk("Unable to read inode block\n"); + return NULL; + } + p = (void *)(*bh)->b_data; + return p + ino % MINIX_INODES_PER_BLOCK; +} + +struct minix2_inode * +minix_V2_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh) +{ + int block; + struct minix_sb_info *sbi = minix_sb(sb); + struct minix2_inode *p; + int minix2_inodes_per_block = sb->s_blocksize / sizeof(struct minix2_inode); + + *bh = NULL; + if (!ino || ino > sbi->s_ninodes) { + printk("Bad inode number on dev %s: %ld is out of range\n", + sb->s_id, (long)ino); + return NULL; + } + ino--; + block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks + + ino / minix2_inodes_per_block; + *bh = sb_bread(sb, block); + if (!*bh) { + printk("Unable to read inode block\n"); + return NULL; + } + p = (void *)(*bh)->b_data; + return p + ino % minix2_inodes_per_block; +} + +/* Clear the link count and mode of a deleted inode on disk. */ + +static void minix_clear_inode(struct inode *inode) +{ + struct buffer_head *bh = NULL; + + if (INODE_VERSION(inode) == MINIX_V1) { + struct minix_inode *raw_inode; + raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh); + if (raw_inode) { + raw_inode->i_nlinks = 0; + raw_inode->i_mode = 0; + } + } else { + struct minix2_inode *raw_inode; + raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh); + if (raw_inode) { + raw_inode->i_nlinks = 0; + raw_inode->i_mode = 0; + } + } + if (bh) { + mark_buffer_dirty(bh); + brelse (bh); + } +} + +void minix_free_inode(struct inode * inode) +{ + struct super_block *sb = inode->i_sb; + struct minix_sb_info *sbi = minix_sb(inode->i_sb); + struct buffer_head *bh; + int k = sb->s_blocksize_bits + 3; + unsigned long ino, bit; + + ino = inode->i_ino; + if (ino < 1 || ino > sbi->s_ninodes) { + printk("minix_free_inode: inode 0 or nonexistent inode\n"); + return; + } + bit = ino & ((1<>= k; + if (ino >= sbi->s_imap_blocks) { + printk("minix_free_inode: nonexistent imap in superblock\n"); + return; + } + + minix_clear_inode(inode); /* clear on-disk copy */ + + bh = sbi->s_imap[ino]; + spin_lock(&bitmap_lock); + if (!minix_test_and_clear_bit(bit, bh->b_data)) + printk("minix_free_inode: bit %lu already cleared\n", bit); + spin_unlock(&bitmap_lock); + mark_buffer_dirty(bh); +} + +struct inode *minix_new_inode(const struct inode *dir, umode_t mode) +{ + struct super_block *sb = dir->i_sb; + struct minix_sb_info *sbi = minix_sb(sb); + struct inode *inode = new_inode(sb); + struct buffer_head * bh; + int bits_per_zone = 8 * sb->s_blocksize; + unsigned long j; + int i; + + if (!inode) + return ERR_PTR(-ENOMEM); + j = bits_per_zone; + bh = NULL; + spin_lock(&bitmap_lock); + for (i = 0; i < sbi->s_imap_blocks; i++) { + bh = sbi->s_imap[i]; + j = minix_find_first_zero_bit(bh->b_data, bits_per_zone); + if (j < bits_per_zone) + break; + } + if (!bh || j >= bits_per_zone) { + spin_unlock(&bitmap_lock); + iput(inode); + return ERR_PTR(-ENOSPC); + } + if (minix_test_and_set_bit(j, bh->b_data)) { /* shouldn't happen */ + spin_unlock(&bitmap_lock); + printk("minix_new_inode: bit already set\n"); + iput(inode); + return ERR_PTR(-ENOSPC); + } + spin_unlock(&bitmap_lock); + mark_buffer_dirty(bh); + j += i * bits_per_zone; + if (!j || j > sbi->s_ninodes) { + iput(inode); + return ERR_PTR(-EFSCORRUPTED); + } + inode_init_owner(&nop_mnt_idmap, inode, dir, mode); + inode->i_ino = j; + simple_inode_init_ts(inode); + inode->i_blocks = 0; + memset(&minix_i(inode)->u, 0, sizeof(minix_i(inode)->u)); + insert_inode_hash(inode); + mark_inode_dirty(inode); + + return inode; +} + +unsigned long minix_count_free_inodes(struct super_block *sb) +{ + struct minix_sb_info *sbi = minix_sb(sb); + u32 bits = sbi->s_ninodes + 1; + + return count_free(sbi->s_imap, sb->s_blocksize, bits); +} -- cgit v1.3.1