Date: Thu, 12 Mar 2015 05:27:40 +0900 From: Warner Losh <imp@bsdimp.com> To: Ian Lepore <ian@FreeBSD.org> Cc: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org> Subject: Re: BBB freebsd-current backtrace. why? Message-ID: <5C9C39FF-CB6D-45B8-A957-06AC5BF5ED91@bsdimp.com> In-Reply-To: <1426083066.33324.34.camel@freebsd.org> References: <CAKE2PDvJ9dadCZpq7BdWfKUZyNUZ5O2e%2BD1yWaKYQ4TSCW8%2BEQ@mail.gmail.com> <CAA=KUhsE5w85Whxxv0FDhmyC-Rz8YfOsL8MPhB%2BMcrd9QE5-_A@mail.gmail.com> <CAKE2PDszqdzgGCCfqJBV9bvn5vTxTGTCJ0wjHkr4hn5RM5susQ@mail.gmail.com> <1426083066.33324.34.camel@freebsd.org>
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--Apple-Mail=_CB08C7FF-B9EA-4A6B-BCB5-B5D9C0755ECF Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > On Mar 11, 2015, at 11:11 PM, Ian Lepore <ian@FreeBSD.org> wrote: >=20 > On Tue, 2015-03-10 at 21:09 -0700, jungle Boogie wrote: >> Hi Jason, >> On 10 March 2015 at 19:05, Jason Birch <jbirch@jbirch.net> wrote: >>>=20 >>> They're lock order reversals, as enabled by the WITNESS kernel = option. You >>> probably don't need to worry, but it's helpful to check if they've = been >>> reported and, if not, report them. >>>=20 >>> You might be running into this one: >>> http://sources.zabbadoz.net/freebsd/lor/261.html >>>=20 >>> Quick Googling turns up these resources: >>>=20 >>> lock order reversals - what do they mean?: >>> = https://lists.freebsd.org/pipermail/freebsd-current/2003-December/016617.h= tml >>> Glossary of Kernel Options for Debugging: >>> = https://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug-optio= ns.html >>> FreeBSD LOR(lock order reversal)s seen and comments: >>> http://sources.zabbadoz.net/freebsd/lor.html >>=20 >> Based on what Ian says, I hope these BT don't continue. Those threads >> are very likely before the BBB was made...much less had freeBSD >> running, so hopefully some progress has been made with freeBSD. >=20 > The point is that those LORs are harmless. They were declared = harmless > by the gurus who understand them, years ago, and apparently just by > issuing that proclamation, it's a closed subject and we all just have = to > live with the spewage. Except that=E2=80=99s not entirely true. There are some that are known = to be harmless, but others that aren=E2=80=99t. Sadly, there=E2=80=99s no way to mark = the harmless ones in the source. Some LoRs are harmless, others lead to deadlock. Warner --Apple-Mail=_CB08C7FF-B9EA-4A6B-BCB5-B5D9C0755ECF Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJVAKU9AAoJEGwc0Sh9sBEAgEwP/3ACP6oINMsOgVTrLuv+5nR1 vEuoTxH6cVg8KW/hhC1PvCU8PHQMfiLMNqqzB0oJ3xyDL5PWcEcLy5B9gs5li8RU m3CRvCwzuy0VF+I6yVt3NWZqh2VBiwlFzTTjw8AjjA86PN4leT+8YR6Kp7znT7iu 7M84/pkz9FiK8ujt26g8GEULGes1msFNVARrPexqKrWdAMIJjm8ZLpyPYQ717RRr 5WAC+yFVYJ38njsws0vaw9SmXG2q/uu2ouj8VpLXEYl5j68Fz41yjm6Ne+IRULpv CZmJtmhCHODOmK3VqOyVVJNHf24NrPPjfWLoHt1H2hj7NhHVShIZZ3Fx9zq8u9Pj ImUU2fdGpm73FqkALuwjBYjsf91VPLJ1EpNhu9yhk1T6wJg3C81Mwvdusm0YQxgP uV6LM5WIGHbgv0xPbZfCduLKfwZgLKRls9/Cb+/aDyuGywMZexlof/PcpURavMVR RJfAhe/ZegUTqY7iJS403mBPq5w+Gzn3Px5EOJiN+kZQqXn0jGN/VuGYEEePI627 weaKFy37Exbf+Iah+OwJIdMT4at10VMBCs8BCBHv0SjMdhQonVJAX3cPi0oEax6A NqRGkkNSNNh+UOjwLQa6PS6b8i2gnOGTugNYm2Q7HIx69BgddIy9cZKOx68YesaG Rjw8fO0c2wkmPx59kA15 =b6yD -----END PGP SIGNATURE----- --Apple-Mail=_CB08C7FF-B9EA-4A6B-BCB5-B5D9C0755ECF--
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