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>
index | next in thread | previous in thread | raw e-mail
[-- Attachment #1 --] > On Mar 11, 2015, at 11:11 PM, Ian Lepore <ian@FreeBSD.org> wrote: > > 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: >>> >>> 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. >>> >>> You might be running into this one: >>> http://sources.zabbadoz.net/freebsd/lor/261.html >>> >>> Quick Googling turns up these resources: >>> >>> lock order reversals - what do they mean?: >>> https://lists.freebsd.org/pipermail/freebsd-current/2003-December/016617.html >>> Glossary of Kernel Options for Debugging: >>> https://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug-options.html >>> FreeBSD LOR(lock order reversal)s seen and comments: >>> http://sources.zabbadoz.net/freebsd/lor.html >> >> 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. > > 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’s not entirely true. There are some that are known to be harmless, but others that aren’t. Sadly, there’s no way to mark the harmless ones in the source. Some LoRs are harmless, others lead to deadlock. Warner [-- Attachment #2 --] -----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-----home | help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?5C9C39FF-CB6D-45B8-A957-06AC5BF5ED91>