Messages in this thread | | | Date | Wed, 7 Oct 2020 09:54:50 -0500 | From | Josh Poimboeuf <> | Subject | Re: [PATCH] x86/unwind/orc: fix inactive tasks with sp in sp |
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-ENOPARSE on $SUBJECT.
Also please address it to x86@kernel.org, I think the tip maintainers can pick up the fix directly.
Also it might be a good idea to Cc the live-patching mailing list, I presume this causes a livepatch stall?
On Wed, Oct 07, 2020 at 10:19:09AM +0200, Jiri Slaby wrote: > gcc-10 optimizes the scheduler code differently than its predecessors, > depending on DEBUG_SECTION_MISMATCH=y config -- the config sets > -fno-inline-functions-called-once.
Weird. Was GCC ignoring this flag before?
> @@ -663,7 +656,13 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task, > } else { > struct inactive_task_frame *frame = (void *)task->thread.sp; > > - state->sp = task->thread.sp; > + /* > + * @ret_addr is in __schedule _before_ the @frame is pushed to > + * the stack, but @thread.sp is saved in __switch_to_asm only > + * _after_ saving the @frame, so subtract the @frame size, i.e. > + * add it to @thread.sp. > + */ > + state->sp = task->thread.sp + sizeof(*frame);
IMO, the code speaks for itself and the comment may be superfluous.
Otherwise it looks good to me. Thanks for fixing it!
-- Josh
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