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/gen_crc64table.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 88 insertions(+) create mode 100644 lib/crc/gen_crc64table.c (limited to 'lib/crc/gen_crc64table.c') diff --git a/lib/crc/gen_crc64table.c b/lib/crc/gen_crc64table.c new file mode 100644 index 000000000..f2be9f62b --- /dev/null +++ b/lib/crc/gen_crc64table.c @@ -0,0 +1,88 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This host program runs at kernel build time and generates the lookup tables + * used by the generic CRC64 code. + * + * Copyright 2018 SUSE Linux. + * Author: Coly Li + */ +#include +#include + +#define CRC64_ECMA182_POLY 0x42F0E1EBA9EA3693ULL +#define CRC64_NVME_POLY 0x9A6C9329AC4BC9B5ULL + +static uint64_t crc64_table[256] = {0}; +static uint64_t crc64_nvme_table[256] = {0}; + +static void generate_reflected_crc64_table(uint64_t table[256], uint64_t poly) +{ + uint64_t i, j, c, crc; + + for (i = 0; i < 256; i++) { + crc = 0ULL; + c = i; + + for (j = 0; j < 8; j++) { + if ((crc ^ (c >> j)) & 1) + crc = (crc >> 1) ^ poly; + else + crc >>= 1; + } + table[i] = crc; + } +} + +static void generate_crc64_table(uint64_t table[256], uint64_t poly) +{ + uint64_t i, j, c, crc; + + for (i = 0; i < 256; i++) { + crc = 0; + c = i << 56; + + for (j = 0; j < 8; j++) { + if ((crc ^ c) & 0x8000000000000000ULL) + crc = (crc << 1) ^ poly; + else + crc <<= 1; + c <<= 1; + } + + table[i] = crc; + } +} + +static void output_table(uint64_t table[256]) +{ + int i; + + for (i = 0; i < 256; i++) { + printf("\t0x%016" PRIx64 "ULL", table[i]); + if (i & 0x1) + printf(",\n"); + else + printf(", "); + } + printf("};\n"); +} + +static void print_crc64_tables(void) +{ + printf("/* this file is generated - do not edit */\n\n"); + printf("#include \n"); + printf("#include \n\n"); + printf("static const u64 ____cacheline_aligned crc64table[256] = {\n"); + output_table(crc64_table); + + printf("\nstatic const u64 ____cacheline_aligned crc64nvmetable[256] = {\n"); + output_table(crc64_nvme_table); +} + +int main(int argc, char *argv[]) +{ + generate_crc64_table(crc64_table, CRC64_ECMA182_POLY); + generate_reflected_crc64_table(crc64_nvme_table, CRC64_NVME_POLY); + print_crc64_tables(); + return 0; +} -- cgit v1.3.1