Re: boot flooded with unwind: Index not found

Russell King (Oracle)
2022-03-02T11:12:56Z

On Wed, Mar 02, 2022 at 11:09:49AM +0100, Corentin Labbe wrote:
> The crash disappeared (but the suspicious RCU usage is still here).

As the trace on those is:

[ 0.239629] unwind_backtrace from show_stack+0x10/0x14
[ 0.239654] show_stack from init_stack+0x1c54/0x2000

unwind_backtrace() and show_stack() are both C code, the compiler will
emit the unwind information for it. show_stack() isn't called from
assembly code, only from C code, so the next function's unwind
information should also be generated by the compiler.

However, init_stack is not a function - it's an array of unsigned long.
There is no way this should appear in the trace, and this suggests that
the unwind of show_stack() has gone wrong.

I don't see anything obvious in Ard's changes that would cause that
though.

Did it used to work fine with previous versions of linux-next - those
versions where we had Ard's "arm-vmap-stacks-v6" tag merged in
(commit 2fa394824493) and did this only appear when I merged
"arm-ftrace-for-rmk" (commit 74aaaa1e9bba) ? Did merging
"arm-ftrace-for-rmk" cause any change in your .config?

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