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 --- drivers/misc/altera-stapl/altera-comp.c | 128 ++++++++++++++++++++++++++++++++ 1 file changed, 128 insertions(+) create mode 100644 drivers/misc/altera-stapl/altera-comp.c (limited to 'drivers/misc/altera-stapl/altera-comp.c') diff --git a/drivers/misc/altera-stapl/altera-comp.c b/drivers/misc/altera-stapl/altera-comp.c new file mode 100644 index 000000000..4a63f51cc --- /dev/null +++ b/drivers/misc/altera-stapl/altera-comp.c @@ -0,0 +1,128 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * altera-comp.c + * + * altera FPGA driver + * + * Copyright (C) Altera Corporation 1998-2001 + * Copyright (C) 2010 NetUP Inc. + * Copyright (C) 2010 Igor M. Liplianin + */ + +#include +#include "altera-exprt.h" + +#define SHORT_BITS 16 +#define CHAR_BITS 8 +#define DATA_BLOB_LENGTH 3 +#define MATCH_DATA_LENGTH 8192 +#define ALTERA_REQUEST_SIZE 1024 +#define ALTERA_BUFFER_SIZE (MATCH_DATA_LENGTH + ALTERA_REQUEST_SIZE) + +static u32 altera_bits_req(u32 n) +{ + u32 result = SHORT_BITS; + + if (n == 0) + result = 1; + else { + /* Look for the highest non-zero bit position */ + while ((n & (1 << (SHORT_BITS - 1))) == 0) { + n <<= 1; + --result; + } + } + + return result; +} + +static u32 altera_read_packed(u8 *buffer, u32 bits, u32 *bits_avail, + u32 *in_index) +{ + u32 result = 0; + u32 shift = 0; + u32 databyte = 0; + + while (bits > 0) { + databyte = buffer[*in_index]; + result |= (((databyte >> (CHAR_BITS - *bits_avail)) + & (0xff >> (CHAR_BITS - *bits_avail))) << shift); + + if (bits <= *bits_avail) { + result &= (0xffff >> (SHORT_BITS - (bits + shift))); + *bits_avail -= bits; + bits = 0; + } else { + ++(*in_index); + shift += *bits_avail; + bits -= *bits_avail; + *bits_avail = CHAR_BITS; + } + } + + return result; +} + +u32 altera_shrink(u8 *in, u32 in_length, u8 *out, u32 out_length, s32 version) +{ + u32 i, j, data_length = 0L; + u32 offset, length; + u32 match_data_length = MATCH_DATA_LENGTH; + u32 bits_avail = CHAR_BITS; + u32 in_index = 0L; + + if (version > 0) + --match_data_length; + + for (i = 0; i < out_length; ++i) + out[i] = 0; + + /* Read number of bytes in data. */ + for (i = 0; i < sizeof(in_length); ++i) { + data_length = data_length | ( + altera_read_packed(in, + CHAR_BITS, + &bits_avail, + &in_index) << (i * CHAR_BITS)); + } + + if (data_length > out_length) { + data_length = 0L; + return data_length; + } + + i = 0; + while (i < data_length) { + /* A 0 bit indicates literal data. */ + if (altera_read_packed(in, 1, &bits_avail, + &in_index) == 0) { + for (j = 0; j < DATA_BLOB_LENGTH; ++j) { + if (i < data_length) { + out[i] = (u8)altera_read_packed(in, + CHAR_BITS, + &bits_avail, + &in_index); + i++; + } + } + } else { + /* A 1 bit indicates offset/length to follow. */ + offset = altera_read_packed(in, altera_bits_req((s16) + (i > match_data_length ? + match_data_length : i)), + &bits_avail, + &in_index); + length = altera_read_packed(in, CHAR_BITS, + &bits_avail, + &in_index); + for (j = 0; j < length; ++j) { + if (i < data_length) { + out[i] = out[i - offset]; + i++; + } + } + } + } + + return data_length; +} -- cgit v1.3.1