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/kunit/string-stream.h | 62 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 lib/kunit/string-stream.h (limited to 'lib/kunit/string-stream.h') diff --git a/lib/kunit/string-stream.h b/lib/kunit/string-stream.h new file mode 100644 index 000000000..7be2450c7 --- /dev/null +++ b/lib/kunit/string-stream.h @@ -0,0 +1,62 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * C++ stream style string builder used in KUnit for building messages. + * + * Copyright (C) 2019, Google LLC. + * Author: Brendan Higgins + */ + +#ifndef _KUNIT_STRING_STREAM_H +#define _KUNIT_STRING_STREAM_H + +#include +#include +#include + +struct string_stream_fragment { + struct list_head node; + char *fragment; +}; + +struct string_stream { + size_t length; + struct list_head fragments; + /* length and fragments are protected by this lock */ + spinlock_t lock; + gfp_t gfp; + bool append_newlines; +}; + +struct kunit; + +struct string_stream *kunit_alloc_string_stream(struct kunit *test, gfp_t gfp); +void kunit_free_string_stream(struct kunit *test, struct string_stream *stream); + +struct string_stream *alloc_string_stream(gfp_t gfp); +void free_string_stream(struct string_stream *stream); + +int __printf(2, 3) string_stream_add(struct string_stream *stream, + const char *fmt, ...); + +int __printf(2, 0) string_stream_vadd(struct string_stream *stream, + const char *fmt, + va_list args); + +void string_stream_clear(struct string_stream *stream); + +char *string_stream_get_string(struct string_stream *stream); + +int string_stream_append(struct string_stream *stream, + struct string_stream *other); + +bool string_stream_is_empty(struct string_stream *stream); + +void string_stream_destroy(struct string_stream *stream); + +static inline void string_stream_set_append_newlines(struct string_stream *stream, + bool append_newlines) +{ + stream->append_newlines = append_newlines; +} + +#endif /* _KUNIT_STRING_STREAM_H */ -- cgit v1.3.1