Hi!
With kernels compiled with gcc-10, on two different machines (AMD Phenom2,
AMD 2990WX) I get the following panic during boot:

[    1.155797] smp: Bringing up secondary CPUs ...
[    1.159823] x86: Booting SMP configuration:
[    1.163720] .... node  #0, CPUs:      #1
[    0.760380] process: Switch to broadcast mode on CPU1
[    1.175723] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: start_secondary+0x177/0x180
[    1.179718] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.7.0-rc2 #1
[    1.179718] Hardware name: System manufacturer System Product Name/M4A77T, BIOS 2401    05/18/2011
[    1.179718] Call Trace:
[    1.179718]  dump_stack+0x50/0x70
[    1.179718]  panic+0xf6/0x2b3
[    1.179718]  ? start_secondary+0x177/0x180
[    1.179718]  __stack_chk_fail+0x10/0x10
[    1.179718]  start_secondary+0x177/0x180
[    1.179718]  secondary_startup_64+0xa4/0xb0
[    1.179718] ---[ end Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: start_secondary+0x177/0x180 ]---

Not reproducible with gcc-9.  Also, it's not a regression as 5.6 and patched
5.5 also fail.  Technically, gcc-10 isn't released yet, but with Fedora
having released with gcc-10 as their default compiler, I find it implausible
that no one among big devs uses it yet, thus it's something specific to my
setups.

One of configs attached.


Meow!
-- 
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⣾⠁⢠⠒⠀⣿⡁ in the beginning was the boot and root floppies and they were good.
⢿⡄⠘⠷⠚⠋⠀                                       -- <willmore> on #linux-sunxi
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