Backtrace stopped: previous frame identical to this frame (corrupt stack?) , even with fresh qemu and linux build

[Chan Kim]

Hello all,

Really strange thing happening here.. I can't see the full stack trace with
'bt' command in gdb.
So I tried with fresh linux-5.10.122 source and qemu-6.2.0 source and it's
happening too!
(it's happening when I do combinations with linux 5.10.0 and qemu-5.1.0. But
it's not happening with linux-5.4.21)

I would be grateful if somebody could check if this happens to other people
or just me.

1. download linux-5.1.122 tarball from https://www.kernel.org/ 
2. uncompress it and set env variable ARCH=arm64,
CROSS_COMPILE=aarch64-none-elf- , do "make defconfig" and "make -j`nproc`
Image"
3. download qemu-6.2.0 from https://www.qemu.org/
4. uncompress it and do "mkdir build" "cd build" "../configure
--target-list=aarch64-softmmu --enable-debug"
5. run qemu and wait for debugger to attach.
qemu-6.2.0/build/aarch64-softmmu/qemu-system-aarch64 -machine
virt,gic-version=max,secure=off,virtualization=true -cpu max -kernel
linux-5.10.112/arch/arm64/boot/Image -m 2G -nographic -netdev
user,id=vnet,hostfwd=:127.0.0.1:0-:22,tftp=/srv/tftp -device
virtio-net-pci,netdev=vnet -machine iommu=smmuv3 --append "root=/dev/ram
init=/init nokaslr earlycon ip=dhcp hugepages=16" -s -S
6. run debugger, do "aarch64-none-elf-gdb linux-6.10.112/vmlinux -x
gdb_script"
(gdb_script content : 
target remote :1234
layout src
b start_kernel
b __driver_attach
)

Now, in gdb, when you press 'c' twice, it'll stop at the first
__driver_attach. (first one stops at start_kernel).
When you are at __attach_driver, type 'bt'. See if you see the full function
stack trace.
This is what I see. 
(gdb) bt
#0  __driver_attach (dev=0xffff000002582810, data=0xffff800011dc2358
<dummy_regulator_driver+40>)
    at drivers/base/dd.c:1060
#1  0xffff8000107a3ed0 in bus_for_each_dev (bus=<optimized out>,
start=<optimized out>,
    data=0xffff800011dc2358 <dummy_regulator_driver+40>,
fn=0xffff8000107a6f60 <__driver_attach>)
    at drivers/base/bus.c:305
#2  0xd6d78000107a5c58 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

I used to see more thatn 20 stacks trace but strangely I see only two. 
I can still see many stacks for linux-5.4.21 that I was working with in the
past. 
Could anyone check if this happens to anyone?
I think if I add BLK_DEV_RAM and set initramfs.cpio.gz in the linux build,
the kernel will boot ok to the shell prompt.
Only the gdb can't show the stack levels.

My OS : ubuntu-20.04  5.13.0-35-generic

$ aarch64-none-elf-gdb --version
GNU gdb (GNU Toolchain for the A-profile Architecture 10.2-2020.11
(arm-10.16)) 10.1.90.20201028-git
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Thank you.
Chan Kim