It has been discovered that the remove_proc_entry has a race in the removing
of entries in the proc file system that are siblings. There's no protection
around the traversing and removing of elements that belong in the same
subdirectory.
This subdirectory list is protected in other areas by the BKL. So the BKL was
at first used to protect this area too, but unfortunately, remove_proc_entry
may be called with spinlocks held. The BKL may schedule, so this was not a
solution.
The final solution was to add a new global spin lock to protect this list,
called proc_subdir_lock. This lock now protects the list in
remove_proc_entry, and I also went around looking for other areas that this
list is modified and added this protection there too. Care must be taken
since these locations call several functions that may also schedule.
Since I don't see any location that these functions that modify the
subdirectory list are called by interrupts, the irqsave/restore versions of
the spin lock was _not_ used.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add support to the proc_device_tree file for removing
and updating properties. Remove just removes the
proc file, update changes the data pointer within
the proc file. The remainder of the device-tree
changes occur elsewhere.
Signed-off-by: Dave Boutcher <sleddog@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This patch adds the ability to the SMU driver to recover missing
calibration partitions from the SMU chip itself. It also adds some
dynamic mecanism to /proc/device-tree so that new properties are visible
to userland.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This cleans up the /proc/device-tree representation of the Open Firmware
device-tree on ppc and ppc64. It does the following things:
- Workaround an issue in some Apple device-trees where a property may
exist with the same name as a child node of the parent. We now
simply "drop" the property instead of creating duplicate entries in
/proc with random result...
- Do not try to chop off the "@0" at the end of a node name whose unit
address is 0. This is not useful, inconsistent, and the code was
buggy and didn't always work anyway.
- Do not create symlinks for the short name and unit address parts of a
node. These were never really used, bloated the memory footprint of
the device-tree with useless struct proc_dir_entry and their matching
dentry and inode cache bloat.
This results in smaller code, smaller memory footprint, and a more
accurate view of the tree presented to userland.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Steven Rostedt
Dave C Boutcher
Benjamin Herrenschmidt
Linus Torvalds