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/req.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 fs/fuse/req.c (limited to 'fs/fuse/req.c') diff --git a/fs/fuse/req.c b/fs/fuse/req.c new file mode 100644 index 000000000..a01ee743d --- /dev/null +++ b/fs/fuse/req.c @@ -0,0 +1,99 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include "dev.h" +#include "fuse_i.h" + +static int fuse_fill_creds(struct fuse_mount *fm, struct fuse_args *args, struct mnt_idmap *idmap) +{ + struct fuse_conn *fc = fm->fc; + bool no_idmap = !fm->sb || (fm->sb->s_iflags & SB_I_NOIDMAP); + kuid_t fsuid = mapped_fsuid(idmap, fc->user_ns); + kgid_t fsgid = mapped_fsgid(idmap, fc->user_ns); + + args->pid = pid_nr_ns(task_pid(current), fc->pid_ns); + + if (args->force) { + if (args->nocreds) + return 0; + + if (no_idmap) { + args->uid = from_kuid_munged(fc->user_ns, current_fsuid()); + args->gid = from_kgid_munged(fc->user_ns, current_fsgid()); + } else { + args->uid = FUSE_INVALID_UIDGID; + args->gid = FUSE_INVALID_UIDGID; + } + return 0; + } + + WARN_ON(args->nocreds); + /* + * Keep the old behavior when idmappings support was not + * declared by a FUSE server. + * + * For those FUSE servers who support idmapped mounts, we send UID/GID + * only along with "inode creation" fuse requests, otherwise idmap == + * &invalid_mnt_idmap and req->in.h.{u,g}id will be equal to + * FUSE_INVALID_UIDGID. + */ + if (no_idmap) { + fsuid = current_fsuid(); + fsgid = current_fsgid(); + } + args->uid = from_kuid(fc->user_ns, fsuid); + args->gid = from_kgid(fc->user_ns, fsgid); + + if (no_idmap && unlikely(args->uid == ((uid_t)-1) || args->gid == ((gid_t)-1))) + return -EOVERFLOW; + + return 0; +} + +static int fuse_req_prep(struct fuse_mount *fm, struct fuse_args *args, struct mnt_idmap *idmap) +{ + if (!args->force && fm->fc->conn_error) + return -ECONNREFUSED; + + return fuse_fill_creds(fm, args, idmap); +} + +ssize_t __fuse_simple_request(struct mnt_idmap *idmap, struct fuse_mount *fm, + struct fuse_args *args) +{ + struct fuse_conn *fc = fm->fc; + int err = fuse_req_prep(fm, args, idmap); + + if (err) + return err; + + return fuse_chan_send(fc->chan, args); +} + +int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args, gfp_t gfp_flags) +{ + struct fuse_conn *fc = fm->fc; + int err; + + WARN_ON(args->force && !args->nocreds); + + err = fuse_req_prep(fm, args, &invalid_mnt_idmap); + if (err) + return err; + + return fuse_chan_send_bg(fc->chan, args, gfp_flags); +} +EXPORT_SYMBOL_GPL(fuse_simple_background); + +int fuse_simple_notify_reply(struct fuse_mount *fm, struct fuse_args *args, u64 unique) +{ + struct fuse_conn *fc = fm->fc; + int err; + + WARN_ON(args->force && !args->nocreds); + + err = fuse_req_prep(fm, args, &invalid_mnt_idmap); + if (err) + return err; + + return fuse_chan_send_notify_reply(fc->chan, args, unique); +} -- cgit v1.3.1