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/fuse/xattr.c | 214 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 214 insertions(+) create mode 100644 fs/fuse/xattr.c (limited to 'fs/fuse/xattr.c') diff --git a/fs/fuse/xattr.c b/fs/fuse/xattr.c new file mode 100644 index 000000000..cab2685ac --- /dev/null +++ b/fs/fuse/xattr.c @@ -0,0 +1,214 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * FUSE: Filesystem in Userspace + * Copyright (C) 2001-2016 Miklos Szeredi + */ + +#include "fuse_i.h" + +#include +#include + +int fuse_setxattr(struct inode *inode, const char *name, const void *value, + size_t size, int flags, unsigned int extra_flags) +{ + struct fuse_mount *fm = get_fuse_mount(inode); + FUSE_ARGS(args); + struct fuse_setxattr_in inarg; + int err; + + if (fm->fc->no_setxattr) + return -EOPNOTSUPP; + + memset(&inarg, 0, sizeof(inarg)); + inarg.size = size; + inarg.flags = flags; + inarg.setxattr_flags = extra_flags; + + args.opcode = FUSE_SETXATTR; + args.nodeid = get_node_id(inode); + args.in_numargs = 3; + args.in_args[0].size = fm->fc->setxattr_ext ? + sizeof(inarg) : FUSE_COMPAT_SETXATTR_IN_SIZE; + args.in_args[0].value = &inarg; + args.in_args[1].size = strlen(name) + 1; + args.in_args[1].value = name; + args.in_args[2].size = size; + args.in_args[2].value = value; + err = fuse_simple_request(fm, &args); + if (err == -ENOSYS) { + fm->fc->no_setxattr = 1; + err = -EOPNOTSUPP; + } + if (!err) + fuse_update_ctime(inode); + + return err; +} + +ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value, + size_t size) +{ + struct fuse_mount *fm = get_fuse_mount(inode); + FUSE_ARGS(args); + struct fuse_getxattr_in inarg; + struct fuse_getxattr_out outarg; + ssize_t ret; + + if (fm->fc->no_getxattr) + return -EOPNOTSUPP; + + memset(&inarg, 0, sizeof(inarg)); + inarg.size = size; + args.opcode = FUSE_GETXATTR; + args.nodeid = get_node_id(inode); + args.in_numargs = 2; + args.in_args[0].size = sizeof(inarg); + args.in_args[0].value = &inarg; + args.in_args[1].size = strlen(name) + 1; + args.in_args[1].value = name; + /* This is really two different operations rolled into one */ + args.out_numargs = 1; + if (size) { + args.out_argvar = true; + args.out_args[0].size = size; + args.out_args[0].value = value; + } else { + args.out_args[0].size = sizeof(outarg); + args.out_args[0].value = &outarg; + } + ret = fuse_simple_request(fm, &args); + if (!ret && !size) + ret = min_t(size_t, outarg.size, XATTR_SIZE_MAX); + if (ret == -ENOSYS) { + fm->fc->no_getxattr = 1; + ret = -EOPNOTSUPP; + } + return ret; +} + +static int fuse_verify_xattr_list(char *list, size_t size) +{ + size_t origsize = size; + + while (size) { + size_t thislen = strnlen(list, size); + + if (!thislen || thislen == size) + return -EIO; + + size -= thislen + 1; + list += thislen + 1; + } + + return origsize; +} + +ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size) +{ + struct inode *inode = d_inode(entry); + struct fuse_mount *fm = get_fuse_mount(inode); + FUSE_ARGS(args); + struct fuse_getxattr_in inarg; + struct fuse_getxattr_out outarg; + ssize_t ret; + + if (fuse_is_bad(inode)) + return -EIO; + + if (!fuse_allow_current_process(fm->fc)) + return -EACCES; + + if (fm->fc->no_listxattr) + return -EOPNOTSUPP; + + memset(&inarg, 0, sizeof(inarg)); + inarg.size = size; + args.opcode = FUSE_LISTXATTR; + args.nodeid = get_node_id(inode); + args.in_numargs = 1; + args.in_args[0].size = sizeof(inarg); + args.in_args[0].value = &inarg; + /* This is really two different operations rolled into one */ + args.out_numargs = 1; + if (size) { + args.out_argvar = true; + args.out_args[0].size = size; + args.out_args[0].value = list; + } else { + args.out_args[0].size = sizeof(outarg); + args.out_args[0].value = &outarg; + } + ret = fuse_simple_request(fm, &args); + if (!ret && !size) + ret = min_t(size_t, outarg.size, XATTR_LIST_MAX); + if (ret > 0 && size) + ret = fuse_verify_xattr_list(list, ret); + if (ret == -ENOSYS) { + fm->fc->no_listxattr = 1; + ret = -EOPNOTSUPP; + } + return ret; +} + +int fuse_removexattr(struct inode *inode, const char *name) +{ + struct fuse_mount *fm = get_fuse_mount(inode); + FUSE_ARGS(args); + int err; + + if (fm->fc->no_removexattr) + return -EOPNOTSUPP; + + args.opcode = FUSE_REMOVEXATTR; + args.nodeid = get_node_id(inode); + args.in_numargs = 2; + fuse_set_zero_arg0(&args); + args.in_args[1].size = strlen(name) + 1; + args.in_args[1].value = name; + err = fuse_simple_request(fm, &args); + if (err == -ENOSYS) { + fm->fc->no_removexattr = 1; + err = -EOPNOTSUPP; + } + if (!err) + fuse_update_ctime(inode); + + return err; +} + +static int fuse_xattr_get(const struct xattr_handler *handler, + struct dentry *dentry, struct inode *inode, + const char *name, void *value, size_t size) +{ + if (fuse_is_bad(inode)) + return -EIO; + + return fuse_getxattr(inode, name, value, size); +} + +static int fuse_xattr_set(const struct xattr_handler *handler, + struct mnt_idmap *idmap, + struct dentry *dentry, struct inode *inode, + const char *name, const void *value, size_t size, + int flags) +{ + if (fuse_is_bad(inode)) + return -EIO; + + if (!value) + return fuse_removexattr(inode, name); + + return fuse_setxattr(inode, name, value, size, flags, 0); +} + +static const struct xattr_handler fuse_xattr_handler = { + .prefix = "", + .get = fuse_xattr_get, + .set = fuse_xattr_set, +}; + +const struct xattr_handler * const fuse_xattr_handlers[] = { + &fuse_xattr_handler, + NULL +}; -- cgit v1.3.1