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SubjectRe: [PATCH v2 09/11] x86/unwind/orc: Prevent unwinding before ORC initialization
On Sat, Apr 25, 2020 at 05:03:08AM -0500, Josh Poimboeuf wrote:
> 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")
> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
> Reviewed-by: Miroslav Benes <mbenes@suse.cz>

I got a weird error when sending this one:

4.7.1 Error: too much mail from 10.10.114.29

If anybody didn't get it, let me know and I can bounce it.

> ---
> 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 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;
>
> --
> 2.21.1
>

--
Josh

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