Date: Sun, 26 Oct 2014 12:53:30 +0100 From: Fabian Keil <freebsd-listen@fabiankeil.de> Cc: FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: Panic after USB deadlock followed by kldunload umass.ko Message-ID: <7af2d4d6.5c73ae4f@fabiankeil.de> In-Reply-To: <5449119B.8090401@selasky.org> References: <03fafb9a.529c7f26@fabiankeil.de> <5449119B.8090401@selasky.org>
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[-- Attachment #1 --] Hans Petter Selasky <hps@selasky.org> wrote: > On 10/23/14 16:28, Fabian Keil wrote: > > kldunload umass.ko lead to a panic, dumping didn't work. > > > > Screenshots are available at: > > http://www.fabiankeil.de/bilder/freebsd/kernel-panic-r273434-usb/ > > > > I've seen locked-up usbconfig processes in the past, > > usually after executing a shell function that does: > > > > | usbconfig_output="$(sudo usbconfig -d ${device} add_quirk UQ_MSC_NO_INQUIRY)" > > | [... error handling snipped ] > > | usbconfig_output="$(sudo usbconfig -d ${device} reset)" > > > > Sometimes the second command seems to mess up the USB system. > USB detach is synchronous. If for example umass fails to detach, due to > reference counts not reaching zero, that might be the root cause. Try to > get a backtrace from the "usb_process()" processes using kgdb, and > you'll see right away what is going on. Thanks for the quick response. So far I haven't been able to intentionally reproduce the issue, but I'll try the above the next time I unintentionally run into this again. Fabian [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iEYEARECAAYFAlRM4LoACgkQBYqIVf93VJ0/5ACePA2VOIuPTluXisMcoEffN1Ha wYYAn1CPV4W8B9yBuhwPN6zcTfJJtPER =eLqz -----END PGP SIGNATURE-----help
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