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  1. 27 May, 2005 3 commits
    • Paul Jackson's avatar
      [PATCH] cpuset exit NULL dereference fix · 2efe86b8
      Paul Jackson authored 
      There is a race in the kernel cpuset code, between the code
to handle notify_on_release, and the code to remove a cpuset.
The notify_on_release code can end up trying to access a
cpuset that has been removed.  In the most common case, this
causes a NULL pointer dereference from the routine cpuset_path.
However all manner of bad things are possible, in theory at least.

The existing code decrements the cpuset use count, and if the
count goes to zero, processes the notify_on_release request,
if appropriate.  However, once the count goes to zero, unless we
are holding the global cpuset_sem semaphore, there is nothing to
stop another task from immediately removing the cpuset entirely,
and recycling its memory.

The obvious fix would be to always hold the cpuset_sem
semaphore while decrementing the use count and dealing with
notify_on_release.  However we don't want to force a global
semaphore into the mainline task exit path, as that might create
a scaling problem.

The actual fix is almost as easy - since this is only an issue
for cpusets using notify_on_release, which the top level big
cpusets don't normally need to use, only take the cpuset_sem
for cpusets using notify_on_release.

This code has been run for hours without a hiccup, while running
a cpuset create/destroy stress test that could crash the existing
kernel in seconds.  This patch applies to the current -linus
git kernel.
Signed-off-by: default avatarPaul Jackson <pj@sgi.com>
Acked-by: default avatarSimon Derr <simon.derr@bull.net>
Acked-by: default avatarDinakar Guniguntala <dino@in.ibm.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      2efe86b8
    • Alan Cox's avatar
      [PATCH] remove non-cleanroom pwc driver compression · 88c18346
      Alan Cox authored 
      The original pwc author raised some questions about the reverse
engineering of the decompressor algorithms used in the pwc driver.
Having done some detailed investigation it appears those concerns that
clean room policy was not followed are reasonable.  I've also had a
friendly discussion with Philips to ask their view on this.

This removes the problem items of code which reduces the pwc
functionality in the kernel a little but leaves all the framework for
setup that will be needed for decompressors in user space (where they
eventually belong).  This change set is designed to be the minimal risk
change set given that 2.6.12 is hopefully close to hand, with a view to
merging the much updated pwc code in 2.6.13 series kernels.

Someone else can then redo the decompressors properly (clean room) in
user space.

Note that while its easy to say that it should have been caught earlier,
but the violation was really only obvious to someone who had access to
both the proprietary source and the 'GPL' source.
      88c18346
    • Linus Torvalds's avatar
      ide-cd: revert DMA mask test change · 5d9e4ea5
      Linus Torvalds authored 
      The change to require the DMA length to be only word-aligned was not
safe.
      5d9e4ea5
  3. 26 May, 2005 28 commits
  5. 25 May, 2005 9 commits
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