Date: Thu, 21 Jun 2012 12:51:41 +0300 From: Alexander Motin <mav@FreeBSD.org> To: Sergey Kandaurov <pluknet@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Oliver Fromme <olli@lurza.secnetix.de> Subject: Re: svn commit: r237335 - head/sys/cam/scsi Message-ID: <4FE2EEAD.3070706@FreeBSD.org> In-Reply-To: <CAE-mSOJ6YV0f=NH%2BH4_rbrawOzG8_HcVqtwL%2Br0MVj9L64PN0g@mail.gmail.com> References: <201206201825.q5KIPpjQ060916@svn.freebsd.org> <CAE-mSOJ6YV0f=NH%2BH4_rbrawOzG8_HcVqtwL%2Br0MVj9L64PN0g@mail.gmail.com>
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On 06/21/12 12:30, Sergey Kandaurov wrote: > On 20 June 2012 22:25, Alexander Motin<mav@freebsd.org> wrote: >> Author: mav >> Date: Wed Jun 20 18:25:51 2012 >> New Revision: 237335 >> URL: http://svn.freebsd.org/changeset/base/237335 >> >> Log: >> Check status of cam_periph_hold() inside cdclose(). If cd device was >> invalidated while open, cam_periph_hold() will return error and won't >> get the reference. Following reference release will crash the system. >> >> Sponsored by: iXsystems, Inc. >> MFC after: 3 days >> >> Modified: >> head/sys/cam/scsi/scsi_cd.c >> >> Modified: head/sys/cam/scsi/scsi_cd.c >> ============================================================================== >> --- head/sys/cam/scsi/scsi_cd.c Wed Jun 20 18:00:26 2012 (r237334) >> +++ head/sys/cam/scsi/scsi_cd.c Wed Jun 20 18:25:51 2012 (r237335) >> @@ -1041,6 +1041,7 @@ cdclose(struct disk *dp) >> { >> struct cam_periph *periph; >> struct cd_softc *softc; >> + int error; >> >> periph = (struct cam_periph *)dp->d_drv1; >> if (periph == NULL) >> @@ -1049,7 +1050,11 @@ cdclose(struct disk *dp) >> softc = (struct cd_softc *)periph->softc; >> >> cam_periph_lock(periph); >> - cam_periph_hold(periph, PRIBIO); >> + if ((error = cam_periph_hold(periph, PRIBIO)) != 0) { >> + cam_periph_unlock(periph); >> + cam_periph_release(periph); >> + return (0); >> + } >> >> CAM_DEBUG(periph->path, CAM_DEBUG_TRACE | CAM_DEBUG_PERIPH, >> ("cdclose\n")); > > Does it fix the reported crash with cd refcount underflow? It seems so. > http://lists.freebsd.org/pipermail/freebsd-stable/2012-June/068175.html Yes, I think it should. At least diagnostics looks very alike. -- Alexander Motin
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