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/sysctl.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 fs/fuse/sysctl.c (limited to 'fs/fuse/sysctl.c') diff --git a/fs/fuse/sysctl.c b/fs/fuse/sysctl.c new file mode 100644 index 000000000..74eca5ce9 --- /dev/null +++ b/fs/fuse/sysctl.c @@ -0,0 +1,65 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/fuse/fuse_sysctl.c + * + * Sysctl interface to fuse parameters + */ +#include + +#include "sysctl.h" +#include "fuse_i.h" + +static struct ctl_table_header *fuse_table_header; + +/* Bound by fuse_init_out max_pages, which is a u16 */ +static unsigned int sysctl_fuse_max_pages_limit = 65535; + +/* + * fuse_init_out request timeouts are u16. + * This goes up to ~18 hours, which is plenty for a timeout. + */ +static unsigned int sysctl_fuse_req_timeout_limit = 65535; + +static const struct ctl_table fuse_sysctl_table[] = { + { + .procname = "max_pages_limit", + .data = &fuse_max_pages_limit, + .maxlen = sizeof(fuse_max_pages_limit), + .mode = 0644, + .proc_handler = proc_douintvec_minmax, + .extra1 = SYSCTL_ONE, + .extra2 = &sysctl_fuse_max_pages_limit, + }, + { + .procname = "default_request_timeout", + .data = &fuse_default_req_timeout, + .maxlen = sizeof(fuse_default_req_timeout), + .mode = 0644, + .proc_handler = proc_douintvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = &sysctl_fuse_req_timeout_limit, + }, + { + .procname = "max_request_timeout", + .data = &fuse_max_req_timeout, + .maxlen = sizeof(fuse_max_req_timeout), + .mode = 0644, + .proc_handler = proc_douintvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = &sysctl_fuse_req_timeout_limit, + }, +}; + +int fuse_sysctl_register(void) +{ + fuse_table_header = register_sysctl("fs/fuse", fuse_sysctl_table); + if (!fuse_table_header) + return -ENOMEM; + return 0; +} + +void fuse_sysctl_unregister(void) +{ + unregister_sysctl_table(fuse_table_header); + fuse_table_header = NULL; +} -- cgit v1.3.1