diff options
| author | Miroslav Benes <mbenes@suse.cz> | 2019-10-16 13:33:13 +0200 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2019-11-04 15:33:15 +0100 |
| commit | 7162431dcf72032835d369c8d7b51311df407938 (patch) | |
| tree | 194454e629a477bba5410fc5eab3303c5c089de4 /kernel/livepatch | |
| parent | Linux 5.4-rc6 (diff) | |
| download | linux-7162431dcf72032835d369c8d7b51311df407938.tar.xz linux-7162431dcf72032835d369c8d7b51311df407938.zip | |
ftrace: Introduce PERMANENT ftrace_ops flag
Livepatch uses ftrace for redirection to new patched functions. It means
that if ftrace is disabled, all live patched functions are disabled as
well. Toggling global 'ftrace_enabled' sysctl thus affect it directly.
It is not a problem per se, because only administrator can set sysctl
values, but it still may be surprising.
Introduce PERMANENT ftrace_ops flag to amend this. If the
FTRACE_OPS_FL_PERMANENT is set on any ftrace ops, the tracing cannot be
disabled by disabling ftrace_enabled. Equally, a callback with the flag
set cannot be registered if ftrace_enabled is disabled.
Link: http://lkml.kernel.org/r/20191016113316.13415-2-mbenes@suse.cz
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/livepatch')
| -rw-r--r-- | kernel/livepatch/patch.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c index bd43537702bd..b552cf2d85f8 100644 --- a/kernel/livepatch/patch.c +++ b/kernel/livepatch/patch.c @@ -196,7 +196,8 @@ static int klp_patch_func(struct klp_func *func) ops->fops.func = klp_ftrace_handler; ops->fops.flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_DYNAMIC | - FTRACE_OPS_FL_IPMODIFY; + FTRACE_OPS_FL_IPMODIFY | + FTRACE_OPS_FL_PERMANENT; list_add(&ops->node, &klp_ops); |