From: "Madhavan T. Venkataraman" <firstname.lastname@example.org> To: Mark Brown <email@example.com> Cc: firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com Subject: Re: [RFC PATCH v1 1/1] arm64: Unwinder enhancements for reliable stack trace Date: Wed, 24 Feb 2021 13:26:56 -0600 [thread overview] Message-ID: <firstname.lastname@example.org> (raw) In-Reply-To: <20210224123336.GA4504@sirena.org.uk> On 2/24/21 6:33 AM, Mark Brown wrote: > On Tue, Feb 23, 2021 at 01:20:49PM -0600, Madhavan T. Venkataraman wrote: >> On 2/23/21 1:02 PM, Mark Brown wrote: >>> On Tue, Feb 23, 2021 at 12:12:43PM -0600, email@example.com wrote: > >>>> Reliable stack trace function >>>> ============================= >>>> >>>> Implement arch_stack_walk_reliable(). This function walks the stack like >>>> the existing stack trace functions with a couple of additional checks: > >>> Again, this should be at least one separate patch. How does this ensure >>> that we don't have any issues with any of the various probe mechanisms? >>> If there's no need to explicitly check anything that should be called >>> out in the changelog. > >> I am trying to do this in an incremental fashion. I have to study the probe >> mechanisms a little bit more before I can come up with a solution. But >> if you want to see that addressed in this patch set, I could do that. >> It will take a little bit of time. That is all. > > Handling of the probes stuff seems like it's critical to reliable stack > walk so we shouldn't claim to have support for reliable stack walk > without it. If it was a working implementation we could improve that'd > be one thing but this would be buggy which is a different thing. > OK. I will address the probe stuff in my resend. >>>> + (void) on_accessible_stack(task, stackframe, &info); > >>> Shouldn't we return NULL if we are not on an accessible stack? > >> The prev_fp has already been checked by the unwinder in the previous >> frame. That is why I don't check the return value. If that is acceptable, >> I will add a comment. > > TBH if you're adding the comment it seems like you may as well add the > check, it's not like it's expensive and it means there's no possibility > that some future change could result in this assumption being broken. > OK. I will add the check. Thanks. Madhavan
next prev parent reply other threads:[~2021-02-24 19:28 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bc4761a47ad08ab7fdd555fc8094beb8fc758d33> 2021-02-23 18:12 ` [RFC PATCH v1 0/1] " madvenka 2021-02-23 18:12 ` [RFC PATCH v1 1/1] " madvenka 2021-02-23 19:02 ` Mark Brown 2021-02-23 19:20 ` Madhavan T. Venkataraman 2021-02-24 12:33 ` Mark Brown 2021-02-24 19:26 ` Madhavan T. Venkataraman [this message] 2021-02-24 12:17 ` Mark Rutland 2021-02-24 19:34 ` Madhavan T. Venkataraman 2021-02-25 11:58 ` Mark Rutland 2021-03-01 16:58 ` Madhavan T. Venkataraman
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