Date: Mon, 18 Dec 2017 08:28:34 -0700 From: Warner Losh <imp@bsdimp.com> To: Mark Johnston <markj@freebsd.org> Cc: Warner Losh <imp@freebsd.org>, src-committers <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, Peter Holm <pho@freebsd.org> Subject: Re: svn commit: r326643 - head/sys/cam Message-ID: <CANCZdfqDS1LhsCVtu_D5pTaE3MyMoMS4bKdK9h0ovpeDMqt_GA@mail.gmail.com> In-Reply-To: <CANCZdfrOROVz1W2jQ%2BfsPFwPPXJHE1XqocsfaKN6AgYVO3wSjA@mail.gmail.com> References: <201712062305.vB6N57XP065402@repo.freebsd.org> <20171218145914.GD4235@raichu> <CANCZdfrOROVz1W2jQ%2BfsPFwPPXJHE1XqocsfaKN6AgYVO3wSjA@mail.gmail.com>
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Sorry for the top post, but https://reviews.freebsd.org/D13531 should have a fix. Warner On Mon, Dec 18, 2017 at 8:03 AM, Warner Losh <imp@bsdimp.com> wrote: > > > On Mon, Dec 18, 2017 at 7:59 AM, Mark Johnston <markj@freebsd.org> wrote: > >> 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()? >> > > I debated between a number of different alternatives, but didn't have a > use case for when SCHEDUELR_STOPPED() would be wrong. Now I do. I think > that you are right. I'll make that change. Sorry for the hassle this may > have caused. I'll submit a review and add you as a reviewer today. > > Warner >
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