[klibc] problems when exec()ing /sbin/init from an initramfs

[Martin Hicks]

On Sun, 2003-11-30 at 15:18, Bryan O'Sullivan wrote:
> On Sun, 2003-11-30 at 11:50, Martin Hicks wrote:
> 
> > Investigating will continue...
> 
> Can you get a sysrq-t dump from the kernel after the hang?  This may
> indicate what's up.
> 

sysrq-t didn't give anything useful.  I tracked it down.

It's spinning in the loop in fs/namespace.c::check_mnt()

Here's some useful debug output:

mnt->mnt_devname = /udev/xscsi/pci20.01.1-1/target2/lun0/part2
mnt->mnt_parent->mnt_devname = rootfs
spin mnt(e0000040401bc380) mnt_parent(e0000040401bc980)
spin mnt(e0000040401bc980) mnt_parent(e0000040401bc380)
spin mnt(e0000040401bc380) mnt_parent(e0000040401bc980)
spin mnt(e0000040401bc980) mnt_parent(e0000040401bc380)
spin mnt(e0000040401bc380) mnt_parent(e0000040401bc980)
spin mnt(e0000040401bc980) mnt_parent(e0000040401bc380)
spin mnt(e0000040401bc380) mnt_parent(e0000040401bc980)


Here's my modified function:

static int check_mnt(struct vfsmount *mnt)
{
        printk("mnt->mnt_devname = %s\n", mnt->mnt_devname);
        printk("mnt->mnt_parent->mnt_devname = %s\n", mnt->mnt_parent->mnt_devname);
        spin_lock(&vfsmount_lock);
        while (mnt->mnt_parent != mnt) {
                printk(KERN_CRIT "spin mnt(%p) mnt_parent(%p)\n", mnt, mnt->mnt_parent);
                mnt = mnt->mnt_parent;
        }
        spin_unlock(&vfsmount_lock);
        return mnt == current->namespace->root;
}



The problem, clearly, is that this circular "parent" link must go away. 
I'm not sure which one is right, but I suspect that mnt_parent for my
stupid device name ("/udev/xscsi/pci20.01.1-1/target2/lun0/part2")
should be rootfs and mnt_parent of rootfs should be rootfs.

Wrong?
mh

-- 
Martin Hicks || mort at bork.org || PGP/GnuPG: 0x4C7F2BEE
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