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/ocfs2/locks.c | 125 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 fs/ocfs2/locks.c (limited to 'fs/ocfs2/locks.c') diff --git a/fs/ocfs2/locks.c b/fs/ocfs2/locks.c new file mode 100644 index 000000000..6de944818 --- /dev/null +++ b/fs/ocfs2/locks.c @@ -0,0 +1,125 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * locks.c + * + * Userspace file locking support + * + * Copyright (C) 2007 Oracle. All rights reserved. + */ + +#include +#include +#include + +#include + +#include "ocfs2.h" + +#include "dlmglue.h" +#include "file.h" +#include "inode.h" +#include "locks.h" + +static int ocfs2_do_flock(struct file *file, struct inode *inode, + int cmd, struct file_lock *fl) +{ + int ret = 0, level = 0, trylock = 0; + struct ocfs2_file_private *fp = file->private_data; + struct ocfs2_lock_res *lockres = &fp->fp_flock; + + if (lock_is_write(fl)) + level = 1; + if (!IS_SETLKW(cmd)) + trylock = 1; + + mutex_lock(&fp->fp_mutex); + + if (lockres->l_flags & OCFS2_LOCK_ATTACHED && + lockres->l_level > LKM_NLMODE) { + int old_level = 0; + struct file_lock request; + + if (lockres->l_level == LKM_EXMODE) + old_level = 1; + + if (level == old_level) + goto out; + + /* + * Converting an existing lock is not guaranteed to be + * atomic, so we can get away with simply unlocking + * here and allowing the lock code to try at the new + * level. + */ + + locks_init_lock(&request); + request.c.flc_type = F_UNLCK; + request.c.flc_flags = FL_FLOCK; + locks_lock_file_wait(file, &request); + + ocfs2_file_unlock(file); + } + + ret = ocfs2_file_lock(file, level, trylock); + if (ret) { + if (ret == -EAGAIN && trylock) + ret = -EWOULDBLOCK; + else + mlog_errno(ret); + goto out; + } + + ret = locks_lock_file_wait(file, fl); + if (ret) + ocfs2_file_unlock(file); + +out: + mutex_unlock(&fp->fp_mutex); + + return ret; +} + +static int ocfs2_do_funlock(struct file *file, int cmd, struct file_lock *fl) +{ + int ret; + struct ocfs2_file_private *fp = file->private_data; + + mutex_lock(&fp->fp_mutex); + ocfs2_file_unlock(file); + ret = locks_lock_file_wait(file, fl); + mutex_unlock(&fp->fp_mutex); + + return ret; +} + +/* + * Overall flow of ocfs2_flock() was influenced by gfs2_flock(). + */ +int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl) +{ + struct inode *inode = file->f_mapping->host; + struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); + + if (!(fl->c.flc_flags & FL_FLOCK)) + return -ENOLCK; + + if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) || + ocfs2_mount_local(osb)) + return locks_lock_file_wait(file, fl); + + if (lock_is_unlock(fl)) + return ocfs2_do_funlock(file, cmd, fl); + else + return ocfs2_do_flock(file, inode, cmd, fl); +} + +int ocfs2_lock(struct file *file, int cmd, struct file_lock *fl) +{ + struct inode *inode = file->f_mapping->host; + struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); + + if (!(fl->c.flc_flags & FL_POSIX)) + return -ENOLCK; + + return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl); +} -- cgit v1.3.1