Date: Mon, 18 Dec 2017 09:59:14 -0500 From: Mark Johnston <markj@FreeBSD.org> To: Warner Losh <imp@FreeBSD.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org, pho@FreeBSD.org Subject: Re: svn commit: r326643 - head/sys/cam Message-ID: <20171218145914.GD4235@raichu> In-Reply-To: <201712062305.vB6N57XP065402@repo.freebsd.org> References: <201712062305.vB6N57XP065402@repo.freebsd.org>
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On Wed, Dec 06, 2017 at 11:05:07PM +0000, Warner Losh wrote: > Author: imp > Date: Wed Dec 6 23:05:07 2017 > New Revision: 326643 > URL: https://svnweb.freebsd.org/changeset/base/326643 > > Log: > Make cam_periph_runccb be safe to call when we can only do polling. > > Sponsored by: Netflix > Differential Revision: https://reviews.freebsd.org/D13388 > > Modified: > head/sys/cam/cam_periph.c > head/sys/cam/cam_xpt.c > head/sys/cam/cam_xpt.h > > Modified: head/sys/cam/cam_periph.c > ============================================================================== > --- head/sys/cam/cam_periph.c Wed Dec 6 23:03:34 2017 (r326642) > +++ head/sys/cam/cam_periph.c Wed Dec 6 23:05:07 2017 (r326643) > @@ -1160,7 +1160,11 @@ cam_periph_runccb(union ccb *ccb, > struct bintime *starttime; > struct bintime ltime; > int error; > - > + bool sched_stopped; > + struct mtx *periph_mtx; > + struct cam_periph *periph; > + uint32_t timeout = 1; > + > starttime = NULL; > xpt_path_assert(ccb->ccb_h.path, MA_OWNED); > KASSERT((ccb->ccb_h.flags & CAM_UNLOCKED) == 0, > @@ -1180,21 +1184,47 @@ cam_periph_runccb(union ccb *ccb, > devstat_start_transaction(ds, starttime); > } > > + sched_stopped = SCHEDULER_STOPPED(); It looks like this regresses DDB's "dump" command: while SCHEDULER_STOPPED() will be true after a panic, it is not true after breaking into DDB from the console. pho@ reported the following issue: db:0:allt> call doadump Dumping 2234 out of 65426 MB:panic: sleepq_add: td 0xfffff80003a48000 to sleep on wchan 0xfffffe0000b36ce8 with sleeping prohibited cpuid = 18 time = 1513582125 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0000b36940 vpanic() at vpanic+0x19c/frame 0xfffffe0000b369c0 kassert_panic() at kassert_panic+0x126/frame 0xfffffe0000b36a30 sleepq_add() at sleepq_add+0x34d/frame 0xfffffe0000b36a80 _sleep() at _sleep+0x26c/frame 0xfffffe0000b36b20 cam_periph_runccb() at cam_periph_runccb+0x17d/frame 0xfffffe0000b36c80 dadump() at dadump+0x12a/frame 0xfffffe0000b36ef0 dump_append() at dump_append+0xa5/frame 0xfffffe0000b36f10 blk_write() at blk_write+0x28b/frame 0xfffffe0000b36f50 minidumpsys() at minidumpsys+0x959/frame 0xfffffe0000b37010 ... Wouldn't it be more correct to predicate on "dumping" rather than SCHEDULER_STOPPED()?
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