If a ftrace callback does not supply its own recursion protection and
does not set the RECURSION_SAFE flag in its ftrace_ops, then ftrace will
make a helper trampoline to do so before calling the callback instead of
just calling the callback directly.
The default for ftrace_ops is going to change. It will expect that handlers
provide their own recursion protection, unless its ftrace_ops states
otherwise.
Link: https://lkml.kernel.org/r/20201028115612.990886844@goodmis.org
Link: https://lkml.kernel.org/r/20201106023546.720372267@goodmis.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Meyer <thomas@m3y3r.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
struct ftrace_ops *op,
struct pt_regs *regs)
{
struct ftrace_ops *op,
struct pt_regs *regs)
{
unsigned long flags;
struct pstore_ftrace_record rec = {};
struct pstore_record record = {
unsigned long flags;
struct pstore_ftrace_record rec = {};
struct pstore_record record = {
if (unlikely(oops_in_progress))
return;
if (unlikely(oops_in_progress))
return;
+ bit = ftrace_test_recursion_trylock();
+ if (bit < 0)
+ return;
+
local_irq_save(flags);
rec.ip = ip;
local_irq_save(flags);
rec.ip = ip;
psinfo->write(&record);
local_irq_restore(flags);
psinfo->write(&record);
local_irq_restore(flags);
+ ftrace_test_recursion_unlock(bit);
}
static struct ftrace_ops pstore_ftrace_ops __read_mostly = {
}
static struct ftrace_ops pstore_ftrace_ops __read_mostly = {