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2005-05-27[PATCH] cpuset exit NULL dereference fixPaul Jackson
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: Paul Jackson <pj@sgi.com> Acked-by: Simon Derr <simon.derr@bull.net> Acked-by: Dinakar Guniguntala <dino@in.ibm.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16[PATCH] cpuset: remove function attribute constBenoit Boissinot
gcc-4 warns with include/linux/cpuset.h:21: warning: type qualifiers ignored on function return type cpuset_cpus_allowed is declared with const extern const cpumask_t cpuset_cpus_allowed(const struct task_struct *p); First const should be __attribute__((const)), but the gcc manual explains that: "Note that a function that has pointer arguments and examines the data pointed to must not be declared const. Likewise, a function that calls a non-const function usually must not be const. It does not make sense for a const function to return void." The following patch remove const from the function declaration. Signed-off-by: Benoit Boissinot <benoit.boissinot@ens-lyon.org> Acked-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
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!