linux-kernel - RE: gcc-10: kernel stack is corrupted and fails to boot

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Date:   Wed, 13 May 2020 16:07:57 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Arnd Bergmann' <arnd@...db.de>, Kalle Valo <kvalo@...eaurora.org>
CC:     linux-wireless <linux-wireless@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: gcc-10: kernel stack is corrupted and fails to boot

From: Arnd Bergmann
> Sent: 13 May 2020 17:00
> On Wed, May 13, 2020 at 5:31 PM Kalle Valo <kvalo@...eaurora.org> wrote:
...
> I investigated a little more: This does happen with 'defconfig'
> after all, in my first try I must have missed the '-smp 2' argument
> to qemu, and it ended up working correctly with just one CPU
> but fails now.
> 
> Stepping through the boot process, I see where it crashes
> in start_secondary:
> 
> |        /* to prevent fake stack check failure in clock setup */
> |        boot_init_stack_canary();
> |
> |        x86_cpuinit.setup_percpu_clockev();
> |
> |        wmb();
> |        cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
> 
> The call to cpu_startup_entry() does not succeed, instead
> it jumps to __stack_chk_fail() from there.

Hasn't this already been fixed?
Add:
		asm("");
after cpu_startup_entry() to stop it being tail-called.

	David

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