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 --- crypto/crc32.c | 129 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 129 insertions(+) create mode 100644 crypto/crc32.c (limited to 'crypto/crc32.c') diff --git a/crypto/crc32.c b/crypto/crc32.c new file mode 100644 index 000000000..489cbed94 --- /dev/null +++ b/crypto/crc32.c @@ -0,0 +1,129 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2012 Xyratex Technology Limited + */ + +/* + * This is crypto api shash wrappers to crc32_le. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define CHKSUM_BLOCK_SIZE 1 +#define CHKSUM_DIGEST_SIZE 4 + +/** No default init with ~0 */ +static int crc32_cra_init(struct crypto_tfm *tfm) +{ + u32 *key = crypto_tfm_ctx(tfm); + + *key = 0; + + return 0; +} + +/* + * Setting the seed allows arbitrary accumulators and flexible XOR policy + * If your algorithm starts with ~0, then XOR with ~0 before you set + * the seed. + */ +static int crc32_setkey(struct crypto_shash *hash, const u8 *key, + unsigned int keylen) +{ + u32 *mctx = crypto_shash_ctx(hash); + + if (keylen != sizeof(u32)) + return -EINVAL; + *mctx = get_unaligned_le32(key); + return 0; +} + +static int crc32_init(struct shash_desc *desc) +{ + u32 *mctx = crypto_shash_ctx(desc->tfm); + u32 *crcp = shash_desc_ctx(desc); + + *crcp = *mctx; + + return 0; +} + +static int crc32_update(struct shash_desc *desc, const u8 *data, + unsigned int len) +{ + u32 *crcp = shash_desc_ctx(desc); + + *crcp = crc32_le(*crcp, data, len); + return 0; +} + +/* No final XOR 0xFFFFFFFF, like crc32_le */ +static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out) +{ + put_unaligned_le32(crc32_le(*crcp, data, len), out); + return 0; +} + +static int crc32_finup(struct shash_desc *desc, const u8 *data, + unsigned int len, u8 *out) +{ + return __crc32_finup(shash_desc_ctx(desc), data, len, out); +} + +static int crc32_final(struct shash_desc *desc, u8 *out) +{ + u32 *crcp = shash_desc_ctx(desc); + + put_unaligned_le32(*crcp, out); + return 0; +} + +static int crc32_digest(struct shash_desc *desc, const u8 *data, + unsigned int len, u8 *out) +{ + return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len, out); +} + +static struct shash_alg alg = { + .setkey = crc32_setkey, + .init = crc32_init, + .update = crc32_update, + .final = crc32_final, + .finup = crc32_finup, + .digest = crc32_digest, + .descsize = sizeof(u32), + .digestsize = CHKSUM_DIGEST_SIZE, + + .base.cra_name = "crc32", + .base.cra_driver_name = "crc32-lib", + .base.cra_priority = 100, + .base.cra_flags = CRYPTO_ALG_OPTIONAL_KEY, + .base.cra_blocksize = CHKSUM_BLOCK_SIZE, + .base.cra_ctxsize = sizeof(u32), + .base.cra_module = THIS_MODULE, + .base.cra_init = crc32_cra_init, +}; + +static int __init crc32_mod_init(void) +{ + return crypto_register_shash(&alg); +} + +static void __exit crc32_mod_fini(void) +{ + crypto_unregister_shash(&alg); +} + +module_init(crc32_mod_init); +module_exit(crc32_mod_fini); + +MODULE_AUTHOR("Alexander Boyko "); +MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_CRYPTO("crc32"); -- cgit v1.3.1