Date: Thu, 11 Jan 2018 03:11:41 +0000 (UTC) From: Warner Losh <imp@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r327805 - head/sys/cam Message-ID: <201801110311.w0B3BfB7073744@repo.freebsd.org>
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Author: imp Date: Thu Jan 11 03:11:41 2018 New Revision: 327805 URL: https://svnweb.freebsd.org/changeset/base/327805 Log: When we crash, we'll stop the scheduler before we call the shutdown_post_sync event. For adashutdown, this causes problems because we need to poll for completion of the commands, but we're not yet officially dumping yet, so the code from r326964 assumed we could use the interrupt-driven commands rather than the polled ones. This lead to a hang. Prevent this by also checking to see if the scheduler is stopped to do the polling. Reported by: markj@ Sponsored by: Netflix Differential Review: https://reviews.freebsd.org/D13845 Modified: head/sys/cam/cam_periph.c Modified: head/sys/cam/cam_periph.c ============================================================================== --- head/sys/cam/cam_periph.c Thu Jan 11 00:54:54 2018 (r327804) +++ head/sys/cam/cam_periph.c Thu Jan 11 03:11:41 2018 (r327805) @@ -1187,10 +1187,16 @@ cam_periph_runccb(union ccb *ccb, * scheduler is running in this case, we still need to poll the I/O to * avoid sleeping waiting for the ccb to complete. * - * XXX To avoid locking problems, dumping/polling callers must call + * A panic triggered dump stops the scheduler, any callback from the + * shutdown_post_sync event will run with the scheduler stopped, but + * before we're officially dumping. To avoid hanging in adashutdown + * initiated commands (or other similar situations), we have to test for + * either SCHEDULER_STOPPED() here as well. + * + * To avoid locking problems, dumping/polling callers must call * without a periph lock held. */ - must_poll = dumping; + must_poll = dumping || SCHEDULER_STOPPED(); ccb->ccb_h.cbfcnp = cam_periph_done; /*
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