On 07/22/2009 06:27 PM, Sukadev Bhattiprolu wrote: > | > | Immediate crash. I tried 2.6.18-something (Debian etch kernel) that I > | had lying around on the VM. The result: > > Interesting. > > Attaching test program and Ccing Peter Anvin for any insights. > > | idr_remove called for id=0 which is not allocated. > | [<c01b7abc>] idr_remove+0xd4/0x137 > | [<c01fa871>] release_mem+0x1d5/0x1e1 > | [<c01fb4ec>] release_dev+0x5d6/0x5ee > | [<c011669e>] __wake_up+0x2a/0x3d > | [<c01f9e1f>] tty_ldisc_enable+0x1f/0x21 > | [<c01fabf5>] init_dev+0x378/0x49f > | [<c01fd2e4>] tty_open+0x2a9/0x2e8 > | [<c0161899>] chrdev_open+0x126/0x141 > | [<c0161773>] chrdev_open+0x0/0x141 > | [<c0158b65>] __dentry_open+0xc8/0x1ac > | [<c0158cad>] nameidata_to_filp+0x19/0x28 > | [<c0158ce7>] do_filp_open+0x2b/0x31 > | [<c027fddd>] do_nanosleep+0x43/0x6a > | [<c0125f96>] do_sigaction+0x99/0x156 > | [<c0158d2b>] do_sys_open+0x3e/0xb3 > | [<c0158dcd>] sys_open+0x16/0x18 > | [<c0102c7b>] syscall_call+0x7/0xb > | > | (on the bright side, the machine is still usable afterwards). > | > | However, 2.6.26 (both mine and Debian) survives the test so it may indeed > | be a recent regression (was it broken again after fixing sometime > | between .18 and .26?) > | > | Bisecting... Interesting... I have to say I'm more than a bit surprised that you can mount a filesystem on top of a character device node at all, but there isn't really a fundamental reason why you couldn't do it, so... I am assuming that what causes the problem is that you have found a way (vfsmount) to hold the pts device node busy which doesn't involve the tty subsystem. This isn't inherently a problem, but it does have implications for freeing: in particular, the pts node cannot be removed until the vfsmount is gone, *and* the device number cannot be reclaimed. It sounds like it's the latter piece which causes problems. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
