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/f2fs/hash.c | 137 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 137 insertions(+) create mode 100644 fs/f2fs/hash.c (limited to 'fs/f2fs/hash.c') diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c new file mode 100644 index 000000000..14082fe5e --- /dev/null +++ b/fs/f2fs/hash.c @@ -0,0 +1,137 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * fs/f2fs/hash.c + * + * Copyright (c) 2012 Samsung Electronics Co., Ltd. + * http://www.samsung.com/ + * + * Portions of this code from linux/fs/ext3/hash.c + * + * Copyright (C) 2002 by Theodore Ts'o + */ +#include +#include +#include +#include +#include + +#include "f2fs.h" + +/* + * Hashing code copied from ext3 + */ +#define DELTA 0x9E3779B9 + +static void TEA_transform(unsigned int buf[4], unsigned int const in[]) +{ + __u32 sum = 0; + __u32 b0 = buf[0], b1 = buf[1]; + __u32 a = in[0], b = in[1], c = in[2], d = in[3]; + int n = 16; + + do { + sum += DELTA; + b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b); + b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d); + } while (--n); + + buf[0] += b0; + buf[1] += b1; +} + +static void str2hashbuf(const unsigned char *msg, size_t len, + unsigned int *buf, int num) +{ + unsigned pad, val; + int i; + + pad = (__u32)len | ((__u32)len << 8); + pad |= pad << 16; + + val = pad; + if (len > num * 4) + len = num * 4; + for (i = 0; i < len; i++) { + if ((i % 4) == 0) + val = pad; + val = msg[i] + (val << 8); + if ((i % 4) == 3) { + *buf++ = val; + val = pad; + num--; + } + } + if (--num >= 0) + *buf++ = val; + while (--num >= 0) + *buf++ = pad; +} + +static u32 TEA_hash_name(const u8 *p, size_t len) +{ + __u32 in[8], buf[4]; + + /* Initialize the default seed for the hash checksum functions */ + buf[0] = 0x67452301; + buf[1] = 0xefcdab89; + buf[2] = 0x98badcfe; + buf[3] = 0x10325476; + + while (1) { + str2hashbuf(p, len, in, 4); + TEA_transform(buf, in); + p += 16; + if (len <= 16) + break; + len -= 16; + } + return buf[0] & ~F2FS_HASH_COL_BIT; +} + +/* + * Compute @fname->hash. For all directories, @fname->disk_name must be set. + * For casefolded directories, @fname->usr_fname must be set, and also + * @fname->cf_name if the filename is valid Unicode and is not "." or "..". + */ +void f2fs_hash_filename(const struct inode *dir, struct f2fs_filename *fname) +{ + const u8 *name = fname->disk_name.name; + size_t len = fname->disk_name.len; + + WARN_ON_ONCE(!name); + + if (name_is_dot_dotdot(name, len)) { + fname->hash = 0; + return; + } + +#if IS_ENABLED(CONFIG_UNICODE) + if (IS_CASEFOLDED(dir)) { + /* + * If the casefolded name is provided, hash it instead of the + * on-disk name. If the casefolded name is *not* provided, that + * should only be because the name wasn't valid Unicode or was + * "." or "..", so fall back to treating the name as an opaque + * byte sequence. Note that to handle encrypted directories, + * the fallback must use usr_fname (plaintext) rather than + * disk_name (ciphertext). + */ + WARN_ON_ONCE(!fname->usr_fname->name); + if (fname->cf_name.name) { + name = fname->cf_name.name; + len = fname->cf_name.len; + } else { + name = fname->usr_fname->name; + len = fname->usr_fname->len; + } + if (IS_ENCRYPTED(dir)) { + struct qstr tmp = QSTR_INIT(name, len); + + fname->hash = + cpu_to_le32(fscrypt_fname_siphash(dir, &tmp)); + return; + } + } +#endif + fname->hash = cpu_to_le32(TEA_hash_name(name, len)); +} -- cgit v1.3.1