Date: Fri, 4 Dec 2015 03:51:02 +0100 From: Mateusz Guzik <mjguzik@gmail.com> To: Kirk McKusick <mckusick@mckusick.com> Cc: Rick Macklem <rmacklem@uoguelph.ca>, FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: panic "ffs_checkblk: bad block" on recent -head kernels Message-ID: <20151204025102.GA15514@dft-labs.eu> In-Reply-To: <201512032307.tB3N7mMl001027@chez.mckusick.com> References: <20151203224752.GA19134@dft-labs.eu> <201512032307.tB3N7mMl001027@chez.mckusick.com>
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On Thu, Dec 03, 2015 at 03:07:48PM -0800, Kirk McKusick wrote: > > Date: Thu, 3 Dec 2015 23:47:52 +0100 > > From: Mateusz Guzik <mjguzik@gmail.com> > > To: Rick Macklem <rmacklem@uoguelph.ca> > > Cc: FreeBSD Current <freebsd-current@freebsd.org> > > Subject: Re: panic "ffs_checkblk: bad block" on recent -head kernels > > > > On Thu, Dec 03, 2015 at 05:08:27PM -0500, Rick Macklem wrote: > >> Hi, > >> > >> I get a fairly reproducible panic when doing a full kernel build > >> on a 256Mbyte single core i386 when running recent kernels from -head. > >> > >> The panic is "ffs_checkblk: bad block ..". I don't actually have the > >> block # (although I think it's just 0xfffffffffffffff, given the backtrace), > >> because it runs off the screen. (I looked up the message via the debugger > >> from the first arg. to panic.) > >> > >> Here's the backtrace without all the numbers: > >> panic(c14f4b55, ffffffff, ffffffff, 0, 64,...) > >> ffs_checkblk(ffffffff, 8000, fffffff9c, ffffffff, c4a02454,...) > >> ffs_reallocblks > >> VOP_REALLOCBLKS_APV > >> cluster_write > >> ffs_write > >> VOP_WRITE_APV > >> vn_write > >> vn_io_fault_doio > >> vn_io_fault1 > >> vn_io_fault > >> dofilewrite > >> kern_writev > >> sys_write > >> syscall > >> > >> It doesn't happen on a kernel dated Sep. 30, but does happen on a Nov. 30 one. > >> (I was away from home, so I didn't upgrade kernels for 2 months.) > >> > >> I am slowly doing a binary search for the first kernel rev. where it occurs, > >> but since each build takes hours, it's going to take a while;-). > >> > >> At this point, it doesn't appear to happen on r289278 (just before jeff@'s buffer > >> cache patch). > >> With kernels between r289279-->r290480, I get into the "R" state that > >> was fixed by r290481 before I get a crash. > >> I tried reverting r289405 and r290047 from a recent kernel and the crashes still > >> occurred, so it doesn't appear to be these commits. > >> > >> I am currently testing r290481 to see if the crash occurs for this rev. > >> > >> If anyone has some insight into which commit might cause this, > >> please let me know. > > > > Well, did it crash with r291460 or later? > > > > If so, try the kernel just before that and if that helps, try: > > > > diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c > > index ff37de8..0ad6ef7 100644 > > --- a/sys/kern/vfs_subr.c > > +++ b/sys/kern/vfs_subr.c > > @@ -2783,6 +2783,7 @@ _vdrop(struct vnode *vp, bool locked) > > vp->v_op = NULL; > > #endif > > bzero(&vp->v_un, sizeof(vp->v_un)); > > + vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; > > vp->v_iflag = 0; > > vp->v_vflag = 0; > > bo->bo_flag = 0; > > > > -- > > Mateusz Guzik <mjguzik gmail.com> > > I concur with trying this suggestion. starting with r291460 these > fields were no longer zero'ed when allocating the vnode. So you may > have some residual values in there that are causing trouble. I reviewed the rest of the structure, looks like this is the rest of the fallout. -- Mateusz Guzik <mjguzik gmail.com>
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