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 --- fs/jfs/jfs_debug.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) create mode 100644 fs/jfs/jfs_debug.c (limited to 'fs/jfs/jfs_debug.c') diff --git a/fs/jfs/jfs_debug.c b/fs/jfs/jfs_debug.c new file mode 100644 index 000000000..44b62b3c3 --- /dev/null +++ b/fs/jfs/jfs_debug.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) International Business Machines Corp., 2000-2004 + * Portions Copyright (C) Christoph Hellwig, 2001-2002 + */ + +#include +#include +#include +#include +#include +#include +#include "jfs_incore.h" +#include "jfs_filsys.h" +#include "jfs_debug.h" + +#ifdef PROC_FS_JFS /* see jfs_debug.h */ + +#ifdef CONFIG_JFS_DEBUG +static int jfs_loglevel_proc_show(struct seq_file *m, void *v) +{ + seq_printf(m, "%d\n", jfsloglevel); + return 0; +} + +static int jfs_loglevel_proc_open(struct inode *inode, struct file *file) +{ + return single_open(file, jfs_loglevel_proc_show, NULL); +} + +static ssize_t jfs_loglevel_proc_write(struct file *file, + const char __user *buffer, size_t count, loff_t *ppos) +{ + char c; + + if (get_user(c, buffer)) + return -EFAULT; + + /* yes, I know this is an ASCIIism. --hch */ + if (c < '0' || c > '9') + return -EINVAL; + jfsloglevel = c - '0'; + return count; +} + +static const struct proc_ops jfs_loglevel_proc_ops = { + .proc_open = jfs_loglevel_proc_open, + .proc_read = seq_read, + .proc_lseek = seq_lseek, + .proc_release = single_release, + .proc_write = jfs_loglevel_proc_write, +}; +#endif + +void jfs_proc_init(void) +{ + struct proc_dir_entry *base; + + base = proc_mkdir("fs/jfs", NULL); + if (!base) + return; + +#ifdef CONFIG_JFS_STATISTICS + proc_create_single("lmstats", 0, base, jfs_lmstats_proc_show); + proc_create_single("txstats", 0, base, jfs_txstats_proc_show); + proc_create_single("xtstat", 0, base, jfs_xtstat_proc_show); + proc_create_single("mpstat", 0, base, jfs_mpstat_proc_show); +#endif +#ifdef CONFIG_JFS_DEBUG + proc_create_single("TxAnchor", 0, base, jfs_txanchor_proc_show); + proc_create("loglevel", 0, base, &jfs_loglevel_proc_ops); +#endif +} + +void jfs_proc_clean(void) +{ + remove_proc_subtree("fs/jfs", NULL); +} + +#endif /* PROC_FS_JFS */ -- cgit v1.3.1