From: Josh Poimboeuf jpoimboe@redhat.com
commit 98d0c8ebf77e0ba7c54a9ae05ea588f0e9e3f46e upstream.
If the unwinder is called before the ORC data has been initialized, orc_find() returns NULL, and it tries to fall back to using frame pointers. This can cause some unexpected warnings during boot.
Move the 'orc_init' check from orc_find() to __unwind_init(), so that it doesn't even try to unwind from an uninitialized state.
Fixes: ee9f8fce9964 ("x86/unwind: Add the ORC unwinder") Reviewed-by: Miroslav Benes mbenes@suse.cz Signed-off-by: Josh Poimboeuf jpoimboe@redhat.com Signed-off-by: Ingo Molnar mingo@kernel.org Cc: Andy Lutomirski luto@kernel.org Cc: Dave Jones dsj@fb.com Cc: Jann Horn jannh@google.com Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Cc: Vince Weaver vincent.weaver@maine.edu Link: https://lore.kernel.org/r/069d1499ad606d85532eb32ce39b2441679667d5.158780874... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kernel/unwind_orc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -142,9 +142,6 @@ static struct orc_entry *orc_find(unsign { static struct orc_entry *orc;
- if (!orc_init) - return NULL; - if (ip == 0) return &null_orc_entry;
@@ -582,6 +579,9 @@ EXPORT_SYMBOL_GPL(unwind_next_frame); void __unwind_start(struct unwind_state *state, struct task_struct *task, struct pt_regs *regs, unsigned long *first_frame) { + if (!orc_init) + goto done; + memset(state, 0, sizeof(*state)); state->task = task;