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 Message-ID: <20151203224752.GA19134@dft-labs.eu> In-Reply-To: <802637848.117955972.1449180507630.JavaMail.zimbra@uoguelph.ca> References: <802637848.117955972.1449180507630.JavaMail.zimbra@uoguelph.ca>
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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>
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