linux/kernel/exit.c, branch v2.6.26

signals: fix sigqueue_free() vs __exit_signal() race

2008-05-24T16:56:10Z

__exit_signal() does flush_sigqueue(tsk->pending) outside of ->siglock. This can race with another thread doing sigqueue_free(), we can free the same SIGQUEUE_PREALLOC sigqueue twice or corrupt the pending->list. Note that even sys_exit_group() can trigger this race, not only sys_timer_delete(). Move the callsite of flush_sigqueue(tsk->pending) under ->siglock. This patch doesn't touch flush_sigqueue(->shared_pending) below, it is called when there are no other threads which can play with signals, and sigqueue_free() can't be used outside of our thread group. Signed-off-by: Oleg Nesterov Acked-by: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] split linux/file.h

2008-05-01T17:08:16Z

Initial splitoff of the low-level stuff; taken to fdtable.h Signed-off-by: Al Viro

pids: __set_special_pids: use change_pid() helper

2008-04-30T15:29:49Z

Use change_pid() instead of detach_pid() + attach_pid() in __set_special_pids(). This way task_session() is not NULL in between. Signed-off-by: Oleg Nesterov Cc: "Eric W. Biederman" Cc: Pavel Emelyanov Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ptrace: introduce ptrace_reparented() helper

2008-04-30T15:29:38Z

Add another trivial helper for the sake of grep. It also auto-documents the fact that ->parent != real_parent implies ->ptrace. No functional changes. Signed-off-by: Oleg Nesterov Acked-by: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

document de_thread() with exit_notify() connection

2008-04-30T15:29:38Z

Add a couple of small comments, it is not easy to see what this code does. Signed-off-by: Oleg Nesterov Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

reparent_thread: use same_thread_group()

2008-04-30T15:29:38Z

Trivial, use same_thread_group() in reparent_thread(). Signed-off-by: Oleg Nesterov Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ptrace: introduce task_detached() helper

2008-04-30T15:29:38Z

exit.c has numerous "->exit_signal == -1" comparisons, this check is subtle and deserves a helper. Imho makes the code more parseable for humans. At least it's surely more greppable. Also, a couple of whitespace cleanups. No functional changes. Signed-off-by: Oleg Nesterov Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

signals: do_group_exit(): use signal_group_exit() more consistently

2008-04-30T15:29:33Z

do_group_exit() checks SIGNAL_GROUP_EXIT to avoid taking sighand->siglock. Since ed5d2cac114202fe2978a9cbcab8f5032796d538 exec() doesn't set this flag, we should use signal_group_exit(). This is not needed for correctness, but can speedup the multithreaded exec and makes the code more consistent. Signed-off-by: Oleg Nesterov Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

cgroups: add an owner to the mm_struct

2008-04-29T15:06:10Z

Remove the mem_cgroup member from mm_struct and instead adds an owner. This approach was suggested by Paul Menage. The advantage of this approach is that, once the mm->owner is known, using the subsystem id, the cgroup can be determined. It also allows several control groups that are virtually grouped by mm_struct, to exist independent of the memory controller i.e., without adding mem_cgroup's for each controller, to mm_struct. A new config option CONFIG_MM_OWNER is added and the memory resource controller selects this config option. This patch also adds cgroup callbacks to notify subsystems when mm->owner changes. The mm_cgroup_changed callback is called with the task_lock() of the new task held and is called just prior to changing the mm->owner. I am indebted to Paul Menage for the several reviews of this patchset and helping me make it lighter and simpler. This patch was tested on a powerpc box, it was compiled with both the MM_OWNER config turned on and off. After the thread group leader exits, it's moved to init_css_state by cgroup_exit(), thus all future charges from runnings threads would be redirected to the init_css_set's subsystem. Signed-off-by: Balbir Singh Cc: Pavel Emelianov Cc: Hugh Dickins Cc: Sudhir Kumar Cc: YAMAMOTO Takashi Cc: Hirokazu Takahashi Cc: David Rientjes , Cc: Balbir Singh Acked-by: KAMEZAWA Hiroyuki Acked-by: Pekka Enberg Reviewed-by: Paul Menage Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mempolicy: rename mpol_free to mpol_put

2008-04-28T15:58:23Z

This is a change that was requested some time ago by Mel Gorman. Makes sense to me, so here it is. Note: I retain the name "mpol_free_shared_policy()" because it actually does free the shared_policy, which is NOT a reference counted object. However, ... The mempolicy object[s] referenced by the shared_policy are reference counted, so mpol_put() is used to release the reference held by the shared_policy. The mempolicy might not be freed at this time, because some task attached to the shared object associated with the shared policy may be in the process of allocating a page based on the mempolicy. In that case, the task performing the allocation will hold a reference on the mempolicy, obtained via mpol_shared_policy_lookup(). The mempolicy will be freed when all tasks holding such a reference have called mpol_put() for the mempolicy. Signed-off-by: Lee Schermerhorn Cc: Christoph Lameter Cc: David Rientjes Cc: Mel Gorman Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds