From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Date: Sat, 07 Apr 2012 17:21:38 +0000 Subject: Re: [sparc] BUG: NMI Watchdog detected LOCKUP on CPU0 Message-Id: <1333819298.7150.63.camel@deadeye> MIME-Version: 1 Content-Type: multipart/mixed; boundary="=-mKPtp0WbCUCzCTxPbLT3" List-Id: To: sparclinux@vger.kernel.org --=-mKPtp0WbCUCzCTxPbLT3 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Summary for the SPARC maintainers: The NMI watchdog is firing on Sunfire 280R and Sun Blade2500 systems with one or both processors in cheetah_xcall_deliver(). This has been seen under 3.0, 3.2 and 3.3 and seems to be associated with disk I/O. Full bug log is at: http://bugs.debian.org/648766 On Tue, 2012-04-03 at 20:56 -0400, Kieron Gillespie wrote: > I have also noticed, that if I am reading the trace correctly that in=20 > both of my cases, and the original bug submitter's, and a bug posted on= =20 > old.nabble.com's case the crash always seems to happen when one CPU is= =20 > doing cheetah_xcall_deliver, and the other CPU is in the same=20 > instruction in tl0_irq15. Here is a link to the post. [...] tl0_irq15 seems to be part of the NMI watchdog (for detecting that the kernel has hung), so you should always see that in a backtrace when the NMI watchdog fires. It's not part of the problem. cheetah_xcall_deliver() does appear to be relevant to the problem and it looks like it could loop indefinitely - though presumably only if a processor is behaving strangely? It appears to periodically enable and disable interrupts, but then I'm not sure how the PSTATE.IE and PIL interrupt control fields interact and I don't think this will reset the NMI watchdog. In any case, it seems like there's a serious problem if it's looping for a long time, whether or not interrupts remain disabled. Ben. --=20 Ben Hutchings Larkinson's Law: All laws are basically false. --=-mKPtp0WbCUCzCTxPbLT3 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIVAwUAT4B3oue/yOyVhhEJAQqMRA/+IVMrnB6m5nIpko3GGHbgYFipKZ8u3Y6q zK4CmDwHjdKH1mqRZ6felN5qeRSZADFHrhzivne3G33na+CZe+LFmwghag0+9bRt jtyTmuiEhUzk51vuQxpPDKHAM7OptOmb267M5of6P2jUlTsE/U1uku4/9YjZ9jrE zA1diLsR0vK0jacwmIJmCs6SPa034aizUAGXrXvAgQfaetAAk3MSFxjO5itQXBL1 Ec71n/DzBDdoyC8AGaI/VTSNEsZfclcFBcJ79XN8AAyEHY32emSPd73IL5CGtvOL sCCYpoUr+M7s7PVy+/C64c/h0NIjYd5RofSCDHU/8eGwJ1kn/UU6QTch3WlCDrpL Jz9Jsw5CALzBPPVxdhfS2q0Rv7S8nxa4a3ROweZgx3/gtYfHLuPpNu2/z62uCAc3 SQitinzyz2Ek/m1eZZnhT+qo6sXkxIQIajsR2RE2m4jt4MvBM42nz0gJ/f22Fhu+ lt8rLPFZC2MbjwYK+OyYAsMm6MentIDfaDVp7HOl9AErlNx8nTQGG/pyQIuGONe/ v/CcQqkMhiwJiO4uhV0S4JN2rp7hSr2SfMaTMt4d56XEioV+UwNPUmnUwdrpBvD6 Gg4XYE7aKCss2gDhoVqgsod8vmAPsxSjP/++KgNaOXvaxh3lVD58t5OQSTncxk7f a0FaCBYogtE= =/xGI -----END PGP SIGNATURE----- --=-mKPtp0WbCUCzCTxPbLT3--