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From: james.morse@arm.com (James Morse)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: fix dump_backtrace with NULL tsk
Date: Fri, 23 Sep 2016 16:58:15 +0100	[thread overview]
Message-ID: <57E55117.8080907@arm.com> (raw)
In-Reply-To: <1474642587-22416-1-git-send-email-mark.rutland@arm.com>

Hi Mark,

On 23/09/16 15:56, Mark Rutland wrote:
> In some places, dump_backtrace() is called with a NULL tsk parameter,
> e.g. in bug_handler() in arch/arm64, or indirectly via show_stack() in
> core code. The expectation is that this is treated as if current were
> passed instead of NULL.
> 
> Commit a80a0eb70c358f8c ("arm64: make irq_stack_ptr more robust") didn't
> take this into account, and compares tsk against current *before* we
> check if tsk is NULL.
> 
> Due to this, we won't initialise irq_stack_ptr, and when we try to dump
> the exception regs we may call dump_mem() for memory immediately above
> the IRQ stack range, rather than for the relevant range on the task
> stack.

Bother, I should have spotted that.
Thanks for catching this!

Acked-by: James Morse <james.morse@arm.com>



Thanks,

James

  parent reply	other threads:[~2016-09-23 15:58 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-23 14:56 [PATCH] arm64: fix dump_backtrace with NULL tsk Mark Rutland
2016-09-23 15:52 ` Mark Rutland
2016-09-23 15:58 ` James Morse [this message]
2016-09-23 16:10   ` Mark Rutland

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