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authorJosh Poimboeuf <jpoimboe@redhat.com>2020-04-25 12:03:08 +0200
committerIngo Molnar <mingo@kernel.org>2020-04-25 12:22:29 +0200
commit98d0c8ebf77e0ba7c54a9ae05ea588f0e9e3f46e (patch)
tree3d3bfb9a7258948eb9af32f6a0388a6fe27fe4f2
parentx86/unwind/orc: Don't skip the first frame for inactive tasks (diff)
downloadlinux-98d0c8ebf77e0ba7c54a9ae05ea588f0e9e3f46e.tar.xz
linux-98d0c8ebf77e0ba7c54a9ae05ea588f0e9e3f46e.zip
x86/unwind/orc: Prevent unwinding before ORC initialization
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/069d1499ad606d85532eb32ce39b2441679667d5.1587808742.git.jpoimboe@redhat.com
-rw-r--r--arch/x86/kernel/unwind_orc.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index e9f5a20c69c6..cb11567361cc 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -148,9 +148,6 @@ 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;
@@ -591,6 +588,9 @@ 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;