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/zstd/common/bits.h | 150 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 150 insertions(+) create mode 100644 lib/zstd/common/bits.h (limited to 'lib/zstd/common/bits.h') diff --git a/lib/zstd/common/bits.h b/lib/zstd/common/bits.h new file mode 100644 index 000000000..c5faaa3d7 --- /dev/null +++ b/lib/zstd/common/bits.h @@ -0,0 +1,150 @@ +/* SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause */ +/* + * Copyright (c) Meta Platforms, Inc. and affiliates. + * All rights reserved. + * + * This source code is licensed under both the BSD-style license (found in the + * LICENSE file in the root directory of this source tree) and the GPLv2 (found + * in the COPYING file in the root directory of this source tree). + * You may select, at your option, one of the above-listed licenses. + */ + +#ifndef ZSTD_BITS_H +#define ZSTD_BITS_H + +#include "mem.h" + +MEM_STATIC unsigned ZSTD_countTrailingZeros32_fallback(U32 val) +{ + assert(val != 0); + { + static const U32 DeBruijnBytePos[32] = {0, 1, 28, 2, 29, 14, 24, 3, + 30, 22, 20, 15, 25, 17, 4, 8, + 31, 27, 13, 23, 21, 19, 16, 7, + 26, 12, 18, 6, 11, 5, 10, 9}; + return DeBruijnBytePos[((U32) ((val & -(S32) val) * 0x077CB531U)) >> 27]; + } +} + +MEM_STATIC unsigned ZSTD_countTrailingZeros32(U32 val) +{ + assert(val != 0); +#if (__GNUC__ >= 4) + return (unsigned)__builtin_ctz(val); +#else + return ZSTD_countTrailingZeros32_fallback(val); +#endif +} + +MEM_STATIC unsigned ZSTD_countLeadingZeros32_fallback(U32 val) +{ + assert(val != 0); + { + static const U32 DeBruijnClz[32] = {0, 9, 1, 10, 13, 21, 2, 29, + 11, 14, 16, 18, 22, 25, 3, 30, + 8, 12, 20, 28, 15, 17, 24, 7, + 19, 27, 23, 6, 26, 5, 4, 31}; + val |= val >> 1; + val |= val >> 2; + val |= val >> 4; + val |= val >> 8; + val |= val >> 16; + return 31 - DeBruijnClz[(val * 0x07C4ACDDU) >> 27]; + } +} + +MEM_STATIC unsigned ZSTD_countLeadingZeros32(U32 val) +{ + assert(val != 0); +#if (__GNUC__ >= 4) + return (unsigned)__builtin_clz(val); +#else + return ZSTD_countLeadingZeros32_fallback(val); +#endif +} + +MEM_STATIC unsigned ZSTD_countTrailingZeros64(U64 val) +{ + assert(val != 0); +#if (__GNUC__ >= 4) && defined(__LP64__) + return (unsigned)__builtin_ctzll(val); +#else + { + U32 mostSignificantWord = (U32)(val >> 32); + U32 leastSignificantWord = (U32)val; + if (leastSignificantWord == 0) { + return 32 + ZSTD_countTrailingZeros32(mostSignificantWord); + } else { + return ZSTD_countTrailingZeros32(leastSignificantWord); + } + } +#endif +} + +MEM_STATIC unsigned ZSTD_countLeadingZeros64(U64 val) +{ + assert(val != 0); +#if (__GNUC__ >= 4) + return (unsigned)(__builtin_clzll(val)); +#else + { + U32 mostSignificantWord = (U32)(val >> 32); + U32 leastSignificantWord = (U32)val; + if (mostSignificantWord == 0) { + return 32 + ZSTD_countLeadingZeros32(leastSignificantWord); + } else { + return ZSTD_countLeadingZeros32(mostSignificantWord); + } + } +#endif +} + +MEM_STATIC unsigned ZSTD_NbCommonBytes(size_t val) +{ + if (MEM_isLittleEndian()) { + if (MEM_64bits()) { + return ZSTD_countTrailingZeros64((U64)val) >> 3; + } else { + return ZSTD_countTrailingZeros32((U32)val) >> 3; + } + } else { /* Big Endian CPU */ + if (MEM_64bits()) { + return ZSTD_countLeadingZeros64((U64)val) >> 3; + } else { + return ZSTD_countLeadingZeros32((U32)val) >> 3; + } + } +} + +MEM_STATIC unsigned ZSTD_highbit32(U32 val) /* compress, dictBuilder, decodeCorpus */ +{ + assert(val != 0); + return 31 - ZSTD_countLeadingZeros32(val); +} + +/* ZSTD_rotateRight_*(): + * Rotates a bitfield to the right by "count" bits. + * https://en.wikipedia.org/w/index.php?title=Circular_shift&oldid=991635599#Implementing_circular_shifts + */ +MEM_STATIC +U64 ZSTD_rotateRight_U64(U64 const value, U32 count) { + assert(count < 64); + count &= 0x3F; /* for fickle pattern recognition */ + return (value >> count) | (U64)(value << ((0U - count) & 0x3F)); +} + +MEM_STATIC +U32 ZSTD_rotateRight_U32(U32 const value, U32 count) { + assert(count < 32); + count &= 0x1F; /* for fickle pattern recognition */ + return (value >> count) | (U32)(value << ((0U - count) & 0x1F)); +} + +MEM_STATIC +U16 ZSTD_rotateRight_U16(U16 const value, U32 count) { + assert(count < 16); + count &= 0x0F; /* for fickle pattern recognition */ + return (value >> count) | (U16)(value << ((0U - count) & 0x0F)); +} + +#endif /* ZSTD_BITS_H */ -- cgit v1.3.1