linux-kernel - Re: [PATCH 0/3] IRQ stack support for ARM

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20201008083015.GK1551@shell.armlinux.org.uk>
Date:   Thu, 8 Oct 2020 09:30:15 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Maninder Singh <maninder1.s@...sung.com>
Cc:     ndesaulniers@...gle.com, caij2003@...il.com, tglx@...utronix.de,
        bigeasy@...utronix.de, maz@...nel.org, valentin.schneider@....com,
        vincent.whitchurch@...s.com, nhuck@...gle.com,
        akpm@...ux-foundation.org, 0x7f454c46@...il.com, will@...nel.org,
        a.sahrawat@...sung.com, v.narang@...sung.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/3] IRQ stack support for ARM

On Thu, Oct 08, 2020 at 12:45:30PM +0530, Maninder Singh wrote:
> Observed Stack Overflow on 8KB kernel stack on ARM specially 
> incase on network interrupts, which results in undeterministic behaviour. 
> So there is need for per cpu dedicated IRQ stack for ARM.
> 
> As ARm does not have extra co-processor register
> to save thread info pointer, IRQ stack will be at some
> performance cost, so code is under CONFIG_IRQ_STACK.
> 
> and we don't have much knowledge and set up for CLANG
> and ARM_UNWIND, so dependency added for both cases.
> 
> Tested patch set with QEMU for latest kernel
> and 4.1 kernel for ARM target with same patch set.

You need to investigate and show where and why this is happening. My
guess is you have a network driver that uses a lot of kernel stack
space, which itself would be a bug.

Note that there are compiler versions out there that mis-optimise and
eat stack space - the kernel build should be warning if a function
uses a large amount of stack.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!