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 --- sound/firewire/lib.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 72 insertions(+) create mode 100644 sound/firewire/lib.c (limited to 'sound/firewire/lib.c') diff --git a/sound/firewire/lib.c b/sound/firewire/lib.c new file mode 100644 index 000000000..654e1a605 --- /dev/null +++ b/sound/firewire/lib.c @@ -0,0 +1,72 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * miscellaneous helper functions + * + * Copyright (c) Clemens Ladisch + */ + +#include +#include +#include +#include +#include +#include "lib.h" + +#define ERROR_RETRY_DELAY_MS 20 + +/** + * snd_fw_transaction - send a request and wait for its completion + * @unit: the driver's unit on the target device + * @tcode: the transaction code + * @offset: the address in the target's address space + * @buffer: input/output data + * @length: length of @buffer + * @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the + * request only in that generation; use %FW_QUIET to suppress error + * messages + * + * Submits an asynchronous request to the target device, and waits for the + * response. The node ID and the current generation are derived from @unit. + * On a bus reset or an error, the transaction is retried a few times. + * Returns zero on success, or a negative error code. + */ +int snd_fw_transaction(struct fw_unit *unit, int tcode, + u64 offset, void *buffer, size_t length, + unsigned int flags) +{ + struct fw_device *device = fw_parent_device(unit); + int generation, rcode, tries = 0; + + generation = flags & FW_GENERATION_MASK; + for (;;) { + if (!(flags & FW_FIXED_GENERATION)) { + generation = device->generation; + smp_rmb(); /* node_id vs. generation */ + } + rcode = fw_run_transaction(device->card, tcode, + device->node_id, generation, + device->max_speed, offset, + buffer, length); + + if (rcode == RCODE_COMPLETE) + return 0; + + if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION)) + return -EAGAIN; + + if (rcode_is_permanent_error(rcode) || ++tries >= 3) { + if (!(flags & FW_QUIET)) + dev_err(&unit->device, + "transaction failed: %s\n", + fw_rcode_string(rcode)); + return -EIO; + } + + msleep(ERROR_RETRY_DELAY_MS); + } +} +EXPORT_SYMBOL(snd_fw_transaction); + +MODULE_DESCRIPTION("FireWire audio helper functions"); +MODULE_AUTHOR("Clemens Ladisch "); +MODULE_LICENSE("GPL"); -- cgit v1.3.1