| From | Linus Torvalds <> | Date | Wed, 20 Jul 2022 10:09:37 -0700 | Subject | Re: [patch 00/38] x86/retbleed: Call depth tracking mitigation |
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On Wed, Jul 20, 2022 at 9:57 AM Steven Rostedt <rostedt@goodmis.org> wrote: > > [ 2.488712] WARNING: CPU: 0 PID: 0 at arch/x86/kernel/alternative.c:558 apply_returns+0xa3/0x1ec
That warning is kind of annoying, in how it doesn't actually give any information about where the problem is.
I do note that we only fix up JMP32_INSN_OPCODE, and I wonder if we have a "jmp __x86_return_thunk" that is close enough to the return thunk that it actually uses a byte offset?
But that WARN_ON_ONCE() should probably be changed to actually give some information about where the problem is.
The silly thing is, there's even debug output in that function that you could enable, but it will enable output for the *normal* case, not for the WARN_ON_ONCE() case or the "we didn't do anything" case. That seems a bit backwards.
Linus
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