From 1b4bd44645ac105ef48e9277fd970b071915712d Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Sat, 25 Apr 2020 05:03:08 -0500 Subject: [PATCH] x86/unwind/orc: Prevent unwinding before ORC initialization 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 Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Dave Jones Cc: Jann Horn Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vince Weaver Link: https://lore.kernel.org/r/069d1499ad606d85532eb32ce39b2441679667d5.1587808742.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/unwind_orc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index 4419a16..aba048f 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -142,9 +142,6 @@ static struct orc_entry *orc_find(unsigned long ip) { 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; -- 2.7.4