Date: Fri, 26 Jun 2009 17:36:43 +0400 From: Stanislav Sedov <stas@FreeBSD.org> To: Thomas Backman <serenity@exscape.org> Cc: freebsd-current@freebsd.org, Artem Belevich <fbsdlist@src.cx> Subject: Re: ZFS : panic("sleeping thread") Message-ID: <20090626173643.b4950bc8.stas@FreeBSD.org> In-Reply-To: <AEA6B136-7464-4A8A-A683-69D651B4625B@exscape.org> References: <ed91d4a80905271058mbc1fc68g184def5097080cbc@mail.gmail.com> <993B7B5B-1B6B-48A5-8425-6A1D071335A9@exscape.org> <20090626164639.71a34f62.stas@FreeBSD.org> <AEA6B136-7464-4A8A-A683-69D651B4625B@exscape.org>
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This is a multi-part message in MIME format. --Multipart=_Fri__26_Jun_2009_17_36_43_+0400_S=AiMNjMBQjSjz.x Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 26 Jun 2009 14:59:18 +0200 Thomas Backman <serenity@exscape.org> mentioned: > I could (and might, too), but unfortunately (well, I guess...) I > haven't been able to reproduce this, despite writing a script to > really stress test it. It's either pretty darn random, or I was simply > wrong about the rollback being involved. I've only gotten it once > since I started using -CURRENT in early May(?) so I don't think I > could tell whether the patch helps or not. :( > I think this could be triggered by tailing the file on ZFS that is being writed with reasonable disk activity. BTW, file I sent previously was incorrect. I attached the rigth one. Thanks! -- Stanislav Sedov ST4096-RIPE --Multipart=_Fri__26_Jun_2009_17_36_43_+0400_S=AiMNjMBQjSjz.x Content-Type: text/x-diff; name="kq.diff" Content-Disposition: attachment; filename="kq.diff" Content-Transfer-Encoding: 7bit diff -r b446ba89e2b9 src/sys/kern/kern_event.c --- a/src/sys/kern/kern_event.c Tue Jun 23 17:00:09 2009 +0400 +++ b/src/sys/kern/kern_event.c Fri Jun 26 17:32:43 2009 +0400 @@ -1608,17 +1608,18 @@ * first. */ void -knote(struct knlist *list, long hint, int islocked) +knote(struct knlist *list, long hint, int lockflags) { struct kqueue *kq; struct knote *kn; + int error; if (list == NULL) return; - KNL_ASSERT_LOCK(list, islocked); + KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); - if (!islocked) + if ((lockflags & KNF_LISTLOCKED) == 0) list->kl_lock(list->kl_lockarg); /* @@ -1633,17 +1634,28 @@ kq = kn->kn_kq; if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { KQ_LOCK(kq); - if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { + if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { + KQ_UNLOCK(kq); + } else if ((lockflags & KNF_NOKQLOCK) != 0) { + kn->kn_status |= KN_INFLUX; + KQ_UNLOCK(kq); + error = kn->kn_fop->f_event(kn, hint); + KQ_LOCK(kq); + kn->kn_status &= ~KN_INFLUX; + if (error) + KNOTE_ACTIVATE(kn, 1); + KQ_UNLOCK_FLUX(kq); + } else { kn->kn_status |= KN_HASKQLOCK; if (kn->kn_fop->f_event(kn, hint)) KNOTE_ACTIVATE(kn, 1); kn->kn_status &= ~KN_HASKQLOCK; + KQ_UNLOCK(kq); } - KQ_UNLOCK(kq); } kq = NULL; } - if (!islocked) + if ((lockflags & KNF_LISTLOCKED) == 0) list->kl_unlock(list->kl_lockarg); } diff -r b446ba89e2b9 src/sys/sys/event.h --- a/src/sys/sys/event.h Tue Jun 23 17:00:09 2009 +0400 +++ b/src/sys/sys/event.h Fri Jun 26 17:32:43 2009 +0400 @@ -135,8 +135,14 @@ MALLOC_DECLARE(M_KQUEUE); #endif -#define KNOTE(list, hist, lock) knote(list, hist, lock) -#define KNOTE_LOCKED(list, hint) knote(list, hint, 1) +/* + * Flags for knote call + */ +#define KNF_LISTLOCKED 0x0001 /* knlist is locked */ +#define KNF_NOKQLOCK 0x0002 /* do not keep KQ_LOCK */ + +#define KNOTE(list, hist, flags) knote(list, hist, flags) +#define KNOTE_LOCKED(list, hint) knote(list, hint, KNF_LISTLOCKED) #define KNOTE_UNLOCKED(list, hint) knote(list, hint, 0) #define KNLIST_EMPTY(list) SLIST_EMPTY(&(list)->kl_list) @@ -204,7 +210,7 @@ struct proc; struct knlist; -extern void knote(struct knlist *list, long hint, int islocked); +extern void knote(struct knlist *list, long hint, int lockflags); extern void knote_fork(struct knlist *list, int pid); extern void knlist_add(struct knlist *knl, struct knote *kn, int islocked); extern void knlist_remove(struct knlist *knl, struct knote *kn, int islocked); diff -r b446ba89e2b9 src/sys/sys/mount.h --- a/src/sys/sys/mount.h Tue Jun 23 17:00:09 2009 +0400 +++ b/src/sys/sys/mount.h Fri Jun 26 17:32:43 2009 +0400 @@ -633,7 +633,7 @@ #define VFS_KNOTE_LOCKED(vp, hint) do \ { \ if (((vp)->v_vflag & VV_NOKNOTE) == 0) \ - VN_KNOTE((vp), (hint), 1); \ + VN_KNOTE((vp), (hint), KNF_LISTLOCKED); \ } while (0) #define VFS_KNOTE_UNLOCKED(vp, hint) do \ diff -r b446ba89e2b9 src/sys/sys/vnode.h --- a/src/sys/sys/vnode.h Tue Jun 23 17:00:09 2009 +0400 +++ b/src/sys/sys/vnode.h Fri Jun 26 17:32:43 2009 +0400 @@ -222,9 +222,10 @@ #define VN_KNOTE(vp, b, a) \ do { \ if (!VN_KNLIST_EMPTY(vp)) \ - KNOTE(&vp->v_pollinfo->vpi_selinfo.si_note, (b), (a)); \ + KNOTE(&vp->v_pollinfo->vpi_selinfo.si_note, (b), \ + (a) | KNF_NOKQLOCK); \ } while (0) -#define VN_KNOTE_LOCKED(vp, b) VN_KNOTE(vp, b, 1) +#define VN_KNOTE_LOCKED(vp, b) VN_KNOTE(vp, b, KNF_LISTLOCKED) #define VN_KNOTE_UNLOCKED(vp, b) VN_KNOTE(vp, b, 0) /* --Multipart=_Fri__26_Jun_2009_17_36_43_+0400_S=AiMNjMBQjSjz.x--
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