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 --- lib/crc/crc64-main.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 lib/crc/crc64-main.c (limited to 'lib/crc/crc64-main.c') diff --git a/lib/crc/crc64-main.c b/lib/crc/crc64-main.c new file mode 100644 index 000000000..133703601 --- /dev/null +++ b/lib/crc/crc64-main.c @@ -0,0 +1,93 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Normal 64-bit CRC calculation. + * + * This is a basic crc64 implementation following ECMA-182 specification, + * which can be found from, + * https://www.ecma-international.org/publications/standards/Ecma-182.htm + * + * Dr. Ross N. Williams has a great document to introduce the idea of CRC + * algorithm, here the CRC64 code is also inspired by the table-driven + * algorithm and detail example from this paper. This paper can be found + * from, + * http://www.ross.net/crc/download/crc_v3.txt + * + * crc64table[256] is the lookup table of a table-driven 64-bit CRC + * calculation, which is generated by gen_crc64table.c in kernel build + * time. The polynomial of crc64 arithmetic is from ECMA-182 specification + * as well, which is defined as, + * + * x^64 + x^62 + x^57 + x^55 + x^54 + x^53 + x^52 + x^47 + x^46 + x^45 + + * x^40 + x^39 + x^38 + x^37 + x^35 + x^33 + x^32 + x^31 + x^29 + x^27 + + * x^24 + x^23 + x^22 + x^21 + x^19 + x^17 + x^13 + x^12 + x^10 + x^9 + + * x^7 + x^4 + x + 1 + * + * crc64nvmetable[256] uses the CRC64 polynomial from the NVME NVM Command Set + * Specification and uses least-significant-bit first bit order: + * + * x^64 + x^63 + x^61 + x^59 + x^58 + x^56 + x^55 + x^52 + x^49 + x^48 + x^47 + + * x^46 + x^44 + x^41 + x^37 + x^36 + x^34 + x^32 + x^31 + x^28 + x^26 + x^23 + + * x^22 + x^19 + x^16 + x^13 + x^12 + x^10 + x^9 + x^6 + x^4 + x^3 + 1 + * + * Copyright 2018 SUSE Linux. + * Author: Coly Li + */ + +#include +#include +#include +#include + +#include "crc64table.h" + +static inline u64 __maybe_unused +crc64_be_generic(u64 crc, const u8 *p, size_t len) +{ + while (len--) + crc = (crc << 8) ^ crc64table[(crc >> 56) ^ *p++]; + return crc; +} + +static inline u64 __maybe_unused +crc64_nvme_generic(u64 crc, const u8 *p, size_t len) +{ + while (len--) + crc = (crc >> 8) ^ crc64nvmetable[(crc & 0xff) ^ *p++]; + return crc; +} + +#ifdef CONFIG_CRC64_ARCH +#include "crc64.h" /* $(SRCARCH)/crc64.h */ +#else +#define crc64_be_arch crc64_be_generic +#define crc64_nvme_arch crc64_nvme_generic +#endif + +u64 crc64_be(u64 crc, const void *p, size_t len) +{ + return crc64_be_arch(crc, p, len); +} +EXPORT_SYMBOL_GPL(crc64_be); + +u64 crc64_nvme(u64 crc, const void *p, size_t len) +{ + return ~crc64_nvme_arch(~crc, p, len); +} +EXPORT_SYMBOL_GPL(crc64_nvme); + +#ifdef crc64_mod_init_arch +static int __init crc64_mod_init(void) +{ + crc64_mod_init_arch(); + return 0; +} +subsys_initcall(crc64_mod_init); + +static void __exit crc64_mod_exit(void) +{ +} +module_exit(crc64_mod_exit); +#endif + +MODULE_DESCRIPTION("CRC64 library functions"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1