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/smb/client/unc.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) create mode 100644 fs/smb/client/unc.c (limited to 'fs/smb/client/unc.c') diff --git a/fs/smb/client/unc.c b/fs/smb/client/unc.c new file mode 100644 index 000000000..f6fc5e343 --- /dev/null +++ b/fs/smb/client/unc.c @@ -0,0 +1,69 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2020, Microsoft Corporation. + * + * Author(s): Steve French + * Suresh Jayaraman + * Jeff Layton + */ + +#include +#include +#include +#include +#include "cifsglob.h" +#include "cifsproto.h" + +/* extract the host portion of the UNC string */ +char *extract_hostname(const char *unc) +{ + const char *src; + char *dst, *delim; + unsigned int len; + + /* skip double chars at beginning of string */ + /* BB: check validity of these bytes? */ + if (strlen(unc) < 3) + return ERR_PTR(-EINVAL); + for (src = unc; *src && *src == '\\'; src++) + ; + if (!*src) + return ERR_PTR(-EINVAL); + + /* delimiter between hostname and sharename is always '\\' now */ + delim = strchr(src, '\\'); + if (!delim) + return ERR_PTR(-EINVAL); + + len = delim - src; + dst = kmalloc((len + 1), GFP_KERNEL); + if (dst == NULL) + return ERR_PTR(-ENOMEM); + + memcpy(dst, src, len); + dst[len] = '\0'; + + return dst; +} + +char *extract_sharename(const char *unc) +{ + const char *src; + char *delim, *dst; + + /* skip double chars at the beginning */ + src = unc + 2; + + /* share name is always preceded by '\\' now */ + delim = strchr(src, '\\'); + if (!delim) + return ERR_PTR(-EINVAL); + delim++; + + /* caller has to free the memory */ + dst = kstrdup(delim, GFP_KERNEL); + if (!dst) + return ERR_PTR(-ENOMEM); + + return dst; +} -- cgit v1.3.1