On Mon, Jan 08, 2007 at 07:44:56PM -0500, Josef Sipek wrote: > Today is a good day! > > Andrew Morton included a minimal version of Unionfs in his -mm tree. > > This minimal version of the code lacks some of the features in the full > fledged version, however we'll be cleaning them up and adding them in one at > a time. > > Thank you all who helped to make this possible! and thanks to you all for the hard work. But I have a bug to report. I'm trying out yesterday's 24-patch series on 2.6.20-rc4 (http://thread.gmane.org/gmane.linux.kernel/481661). The root filesystem is a union of a ro squashfs and a rw tmpfs. The initramfs sets it up something like this: mkdir /os mount -r -t squashfs /dev/ram0 /os mkdir /cow mount -t tmpfs -o mode=0755 tmpfs /cow mount -w -o dirs=/cow=rw:/os=ro -t unionfs unionfs /root The system works normally, except that it crashes reliably whenever I run this program: #! /usr/bin/python import glob import os import subprocess import sys def processes(): 'Returns a iterator over (pid, exe) tuples for each running process.' # the kernel appends this to the link target when the running exe has been # unlinked unlinked_suffix = ' (deleted)' subprocess.call('ps axf 1>&2', shell=True) subprocess.call('ls -l /proc/* 1>&2', shell=True) for ed in glob.glob('/proc/*'): print >>sys.stderr, 'looking at %s' % ed try: pid = int(os.path.basename(ed)) except ValueError: # probably /proc/self or something continue print >>sys.stderr, '%s has pid %s' % (ed, pid) try: l = os.path.join(ed, 'exe') print >>sys.stderr, 'reading %s' % l targ = os.readlink(l) except OSError: # building a list of running processes is inherently racy, oh well continue if targ.endswith(unlinked_suffix): targ = targ[:-len(unlinked_suffix)] yield (pid, targ) for p, e in processes(): print >>sys.stderr, p, e here's the oops from running under qemu. More or less the same thing happens in UML kernels too: BUG: unable to handle kernel NULL pointer dereference at virtual address 00000010 printing eip: c015d701 *pde = 00000000 Oops: 0000 [#1] SMP Modules linked in: button ac battery bridge llc unionfs squashfs zlib_inflate rd ext2 dm_mod ide_cd cdrom ide_disk mousedev parport_pc parport floppy serio_raw psmouse piix generic ide_core ata_generic libata pcspkr ne2k_pci 8390 i2c_piix4 i2c_core scsi_mod evdev fan CPU: 0 EIP: 0060:[<c015d701>] Not tainted VLI EFLAGS: 00200202 (2.6.20-rc4-x86 #0) EIP is at __d_path+0x8f/0x154 eax: c68ad42c ebx: c364dffe ecx: 00000000 edx: 00001000 esi: c7a81da0 edi: c6ce6a9c ebp: c364dfff esp: c72f5ec8 ds: 007b es: 007b ss: 0068 Process ls (pid: 1804, ti=c72f5000 task=c7a91ab0 task.ti=c72f5000) Stack: c68ad42c 00000000 c6ce6a9c 00000044 00000001 00000fff c68ad42c c7a81da0 c364d000 00000000 c015ec0e c7a81da0 c364d000 00001000 c6ce6a9c c6ce6a9c c364d000 fffffff4 00000000 c01774b3 00001000 00000001 08061290 00000000 Call Trace: [<c015ec0e>] d_path+0x91/0xbd [<c01774b3>] proc_pid_readlink+0x76/0xdc [<c015246e>] sys_readlinkat+0x83/0x9e [<c01524b0>] sys_readlink+0x27/0x2b [<c0102ccc>] syscall_call+0x7/0xb ======================= Code: ff 2f eb 08 8b 7c 24 10 89 7c 24 08 8b 04 24 39 44 24 08 75 0e 8b 54 24 2c 39 54 24 04 0f 84 c3 00 00 00 8b 7c 24 08 8b 4c 24 04 <3b> 79 10 74 0b 8b 47 18 89 44 24 10 39 c7 75 29 b8 80 f0 2e c0 EIP: [<c015d701>] __d_path+0x8f/0x154 SS:ESP 0068:c72f5ec8 any ideas? Jason - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
