From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Eric Dumazet <edumazet@google.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ingo Molnar <mingo@kernel.org>, Jiri Slaby <jslaby@suse.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 0/3] Kill off show_stack() NULL-implies-current idiom
Date: Mon, 26 Sep 2016 15:01:36 -0500 [thread overview]
Message-ID: <20160926200136.sbltg4tp5uft4yfo@treble> (raw)
In-Reply-To: <1474902979-18436-1-git-send-email-mark.rutland@arm.com>
On Mon, Sep 26, 2016 at 04:16:16PM +0100, Mark Rutland wrote:
> Today, show_stack() accepts a NULL task parameter, which it takes to mean the
> current task. However, as noted in tip/x86/asm commit:
>
> 81539169f283329f ("x86/dumpstack: Remove NULL task pointer convention")
>
> ... having a NULL task parameter imply current leads to subtle bugs in stack
> walking code (so far seen on both 86 and arm64), makes callsites harder to
> read, and is unnecessary as all callers have access to current.
>
> As a step towards removing the problematic NULL-implies-current idiom entirely,
> these patches ensure that generic code explictly passes current to
> show_stack(), rather than relying on arch code to handle NULL.
This is a good step, though it would be really nice to fix this
tree-wide. Do you have any plans to do so?
Regardless, for the series:
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
--
Josh
next prev parent reply other threads:[~2016-09-26 20:01 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-26 15:16 Mark Rutland
2016-09-26 15:16 ` [PATCH 1/3] sched: document that show_stack() should not be passed a NULL task Mark Rutland
2016-09-26 15:16 ` [PATCH 2/3] drivers/tty: Explicitly pass current to show_stack Mark Rutland
2016-09-26 15:16 ` [PATCH 3/3] lib: dump_stack: explicitly " Mark Rutland
2016-09-26 20:01 ` Josh Poimboeuf [this message]
2016-09-26 21:33 ` [PATCH 0/3] Kill off show_stack() NULL-implies-current idiom Mark Rutland
2016-09-27 17:57 ` Mark Rutland
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