[PATCH-4.19-stable 0/2] Backport ENCODE_FRAME_POINTER hint

[Dmitry Safonov]

On 4.19.93 the following warning was observed with CONFIG_FRAME_POINTER:
> WARNING: kernel stack frame pointer at 00000000bceb5183 in Coronavirus:3282 has bad value           (null)
>  unwind stack type:0 next_sp:          (null) mask:0x2 graph_idx:0
>  000000009630aa47: ffffc9000126fdb0 (0xffffc9000126fdb0)
>  0000000020360f53: ffffffff81038e33 (__save_stack_trace+0xcb/0xee)
>  00000000675081f2: 0000000000000000 ...
>  0000000043198fe7: ffffc9000126c000 (0xffffc9000126c000)
>  0000000008a46231: ffffc90001270000 (0xffffc90001270000)
[..]

It turns to be missing %rbp hint was making frame pointer unwinder
a bit tipsy.
The observed is WARN_ONCE(), so it one time per boot, but imho, worth to
have in stable too.

Peter Zijlstra (2):
  x86/stackframe: Move ENCODE_FRAME_POINTER to asm/frame.h
  x86/stackframe, x86/ftrace: Add pt_regs frame annotations

 arch/x86/entry/calling.h     | 15 -----------
 arch/x86/entry/entry_32.S    | 16 ------------
 arch/x86/include/asm/frame.h | 49 ++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/ftrace_32.S  |  3 +++
 arch/x86/kernel/ftrace_64.S  |  3 +++
 5 files changed, 55 insertions(+), 31 deletions(-)

-- 
2.25.0