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authorOleg Nesterov <oleg@redhat.com>2009-07-17 09:09:36 +1000
committerJames Morris <jmorris@namei.org>2009-07-17 09:09:36 +1000
commitd2e3ee9b29f5de5b01e611b04e6fb29760589b01 (patch)
treead73b17c2c6b83050a948685a0a3af3f907de67f /security/selinux
parent713c0ecdb888e9ef6f085e828555455c5916b07f (diff)
downloadop-kernel-dev-d2e3ee9b29f5de5b01e611b04e6fb29760589b01.zip
op-kernel-dev-d2e3ee9b29f5de5b01e611b04e6fb29760589b01.tar.gz
kernel: fix is_single_threaded
- Fix the comment, is_single_threaded(p) actually means that nobody shares ->mm with p. I think this helper should be renamed, and it should not have arguments. With or without this patch it must not be used unless p == current, otherwise we can't safely use p->signal or p->mm. - "if (atomic_read(&p->signal->count) != 1)" is not right when we have a zombie group leader, use signal->live instead. - Add PF_KTHREAD check to skip kernel threads which may borrow p->mm, otherwise we can return the wrong "false". - Use for_each_process() instead of do_each_thread(), all threads must use the same ->mm. - Use down_write(mm->mmap_sem) + rcu_read_lock() instead of tasklist_lock to iterate over the process list. If there is another CLONE_VM process it can't pass exit_mm() which takes the same mm->mmap_sem. We can miss a freshly forked CLONE_VM task, but this doesn't matter because we must see its parent and return false. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: James Morris <jmorris@namei.org> Cc: Roland McGrath <roland@redhat.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/selinux')
0 files changed, 0 insertions, 0 deletions
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