next-20130306 - BUG: unable to handle kernel paging reques in avc_has_perm_noaudit

[Valdis Kletnieks]

Seeing this in next-20130306:

[  180.958482] BUG: unable to handle kernel paging request at ffffffffffffffe0
[  180.958488] IP: [<ffffffff811e5661>] avc_has_perm_noaudit+0xbf/0x1bc

[  180.958506] Pid: 1910, comm: systemd-udevd Tainted: G           O 3.9.0-rc1-next-20130306-dirty #64 Dell Inc. Latitude E6500

[  180.958537]  [<ffffffff811e5790>] avc_has_perm_flags+0x32/0xe4
[  180.958540]  [<ffffffff81071c81>] ? mark_lock+0x2e/0x225
[  180.958543]  [<ffffffff811e5ada>] avc_has_perm+0xf/0x11
[  180.958546]  [<ffffffff811e5e92>] selinux_inode_rename+0x84/0x138
[  180.958549]  [<ffffffff811002b6>] ? __kmalloc_track_caller+0x107/0x119
[  180.958552]  [<ffffffff811e36db>] security_inode_rename+0x6f/0x7a
[  180.958556]  [<ffffffff81115a8f>] vfs_rename+0x1e2/0x36a
[  180.958558]  [<ffffffff81115e04>] SYSC_renameat+0x1ed/0x282
[  180.958562]  [<ffffffff81123485>] ? mntput+0x49/0x50
[  180.958566]  [<ffffffff81068576>] ? __read_seqcount_retry.constprop.21+0x20/0x25
[  180.958568]  [<ffffffff81068b1c>] ? current_kernel_time+0x2a/0x41
[  180.958572]  [<ffffffff81094215>] ? __audit_syscall_entry+0xf9/0x125
[  180.958575]  [<ffffffff8111681f>] SyS_renameat+0x9/0xb
[  180.958577]  [<ffffffff81116837>] SyS_rename+0x16/0x1b
[  180.958581]  [<ffffffff815f55d2>] system_call_fastpath+0x16/0x1b

Most suspicious-looking recent commit in git log:

ommit 65dff759d2948cf18e2029fc5c0c595b8b7da3a5
Author: Li Zefan <lizefan@xxxxxxxxxx>
Date:   Fri Mar 1 15:01:56 2013 +0800

    cgroup: fix cgroup_path() vs rename() race

    rename() will change dentry->d_name. The result of this race can
    be worse than seeing partially rewritten name, but we might access
    a stale pointer because rename() will re-allocate memory to hold
    a longer name.

I admit not having any clue what crazy antics systemd was trying to do
at the time.  If this doesn't ring a bell, I'll go bisect it.

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