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/sysfile.c | 164 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 164 insertions(+) create mode 100644 fs/ocfs2/sysfile.c (limited to 'fs/ocfs2/sysfile.c') diff --git a/fs/ocfs2/sysfile.c b/fs/ocfs2/sysfile.c new file mode 100644 index 000000000..67e492f4b --- /dev/null +++ b/fs/ocfs2/sysfile.c @@ -0,0 +1,164 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * sysfile.c + * + * Initialize, read, write, etc. system files. + * + * Copyright (C) 2002, 2004 Oracle. All rights reserved. + */ + +#include +#include +#include + +#include + +#include "ocfs2.h" + +#include "alloc.h" +#include "dir.h" +#include "inode.h" +#include "journal.h" +#include "sysfile.h" + +#include "buffer_head_io.h" + +static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb, + int type, + u32 slot); + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +static struct lock_class_key ocfs2_sysfile_cluster_lock_key[NUM_SYSTEM_INODES]; +#endif + +static inline int is_global_system_inode(int type) +{ + return type >= OCFS2_FIRST_ONLINE_SYSTEM_INODE && + type <= OCFS2_LAST_GLOBAL_SYSTEM_INODE; +} + +static struct inode **get_local_system_inode(struct ocfs2_super *osb, + int type, + u32 slot) +{ + int index; + struct inode **local_system_inodes, **free = NULL; + + BUG_ON(slot == OCFS2_INVALID_SLOT); + BUG_ON(type < OCFS2_FIRST_LOCAL_SYSTEM_INODE || + type > OCFS2_LAST_LOCAL_SYSTEM_INODE); + + spin_lock(&osb->osb_lock); + local_system_inodes = osb->local_system_inodes; + spin_unlock(&osb->osb_lock); + + if (unlikely(!local_system_inodes)) { + local_system_inodes = + kzalloc(array3_size(sizeof(struct inode *), + NUM_LOCAL_SYSTEM_INODES, + osb->max_slots), + GFP_NOFS); + if (!local_system_inodes) { + mlog_errno(-ENOMEM); + /* + * return NULL here so that ocfs2_get_sytem_file_inodes + * will try to create an inode and use it. We will try + * to initialize local_system_inodes next time. + */ + return NULL; + } + + spin_lock(&osb->osb_lock); + if (osb->local_system_inodes) { + /* Someone has initialized it for us. */ + free = local_system_inodes; + local_system_inodes = osb->local_system_inodes; + } else + osb->local_system_inodes = local_system_inodes; + spin_unlock(&osb->osb_lock); + kfree(free); + } + + index = (slot * NUM_LOCAL_SYSTEM_INODES) + + (type - OCFS2_FIRST_LOCAL_SYSTEM_INODE); + + return &local_system_inodes[index]; +} + +struct inode *ocfs2_get_system_file_inode(struct ocfs2_super *osb, + int type, + u32 slot) +{ + struct inode *inode = NULL; + struct inode **arr = NULL; + + /* avoid the lookup if cached in local system file array */ + if (is_global_system_inode(type)) { + arr = &(osb->global_system_inodes[type]); + } else + arr = get_local_system_inode(osb, type, slot); + + if (arr && ((inode = *arr) != NULL)) { + /* get a ref in addition to the array ref */ + inode = igrab(inode); + BUG_ON(!inode); + + return inode; + } + + /* this gets one ref thru iget */ + inode = _ocfs2_get_system_file_inode(osb, type, slot); + + /* add one more if putting into array for first time */ + if (inode && arr && !*arr && !cmpxchg(&(*arr), NULL, inode)) { + inode = igrab(inode); + BUG_ON(!inode); + } + return inode; +} + +static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb, + int type, + u32 slot) +{ + char namebuf[40]; + struct inode *inode = NULL; + u64 blkno; + int len, status = 0; + + len = ocfs2_sprintf_system_inode_name(namebuf, + sizeof(namebuf), + type, slot); + + status = ocfs2_lookup_ino_from_name(osb->sys_root_inode, + namebuf, len, &blkno); + if (status < 0) { + goto bail; + } + + inode = ocfs2_iget(osb, blkno, OCFS2_FI_FLAG_SYSFILE, type); + if (IS_ERR(inode)) { + mlog_errno(PTR_ERR(inode)); + inode = NULL; + goto bail; + } +#ifdef CONFIG_DEBUG_LOCK_ALLOC + if (type == LOCAL_USER_QUOTA_SYSTEM_INODE || + type == LOCAL_GROUP_QUOTA_SYSTEM_INODE || + type == JOURNAL_SYSTEM_INODE) { + /* Ignore inode lock on these inodes as the lock does not + * really belong to any process and lockdep cannot handle + * that */ + OCFS2_I(inode)->ip_inode_lockres.l_lockdep_map.key = NULL; + } else { + lockdep_init_map(&OCFS2_I(inode)->ip_inode_lockres. + l_lockdep_map, + ocfs2_system_inodes[type].si_name, + &ocfs2_sysfile_cluster_lock_key[type], 0); + } +#endif +bail: + + return inode; +} + -- cgit v1.3.1