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 --- include/crypto/utils.h | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 include/crypto/utils.h (limited to 'include/crypto/utils.h') diff --git a/include/crypto/utils.h b/include/crypto/utils.h new file mode 100644 index 000000000..2594f4577 --- /dev/null +++ b/include/crypto/utils.h @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Cryptographic utilities + * + * Copyright (c) 2023 Herbert Xu + */ +#ifndef _CRYPTO_UTILS_H +#define _CRYPTO_UTILS_H + +#include +#include +#include + +void __crypto_xor(u8 *dst, const u8 *src1, const u8 *src2, unsigned int size); + +static inline void crypto_xor(u8 *dst, const u8 *src, unsigned int size) +{ + if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && + __builtin_constant_p(size) && + (size % sizeof(unsigned long)) == 0) { + unsigned long *d = (unsigned long *)dst; + unsigned long *s = (unsigned long *)src; + unsigned long l; + + while (size > 0) { + l = get_unaligned(d) ^ get_unaligned(s++); + put_unaligned(l, d++); + size -= sizeof(unsigned long); + } + } else { + __crypto_xor(dst, dst, src, size); + } +} + +static inline void crypto_xor_cpy(u8 *dst, const u8 *src1, const u8 *src2, + unsigned int size) +{ + if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && + __builtin_constant_p(size) && + (size % sizeof(unsigned long)) == 0) { + unsigned long *d = (unsigned long *)dst; + unsigned long *s1 = (unsigned long *)src1; + unsigned long *s2 = (unsigned long *)src2; + unsigned long l; + + while (size > 0) { + l = get_unaligned(s1++) ^ get_unaligned(s2++); + put_unaligned(l, d++); + size -= sizeof(unsigned long); + } + } else { + __crypto_xor(dst, src1, src2, size); + } +} + +noinline unsigned long __crypto_memneq(const void *a, const void *b, size_t size); + +/** + * crypto_memneq - Compare two areas of memory without leaking + * timing information. + * + * @a: One area of memory + * @b: Another area of memory + * @size: The size of the area. + * + * Returns 0 when data is equal, 1 otherwise. + */ +static inline int crypto_memneq(const void *a, const void *b, size_t size) +{ + return __crypto_memneq(a, b, size) != 0UL ? 1 : 0; +} + +#endif /* _CRYPTO_UTILS_H */ -- cgit v1.3.1