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sys_personality: remove the bogus checks in sys_personality()->__set_…

…personality() path

Cleanup, no functional changes.

- __set_personality() always changes ->exec_domain/personality, the
  special case when ->exec_domain remains the same buys nothing but
  complicates the code. Unify both cases to simplify the code.

- The -EINVAL check in sys_personality() was never right. If we assume
  that set_personality() can fail we should check the value it returns
  instead of verifying that task->personality was actually changed.

  Remove it. Before the previous patch it was possible to hit this case
  due to overflow problems, but this -EINVAL just indicated the kernel
  bug.

OTOH, probably it makes sense to change lookup_exec_domain() to return
ERR_PTR() instead of default_exec_domain if the search in exec_domains
list fails, and report this error to the user-space.  But this means
another user-space change, and we have in-kernel users which need fixes.
For example, PER_OSF4 falls into PER_MASK for unkown reason and nobody
cares to register this domain.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Wenming Zhang <wezhang@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1 parent 5bf1d29 commit 2ee7c922f20c96dba56fd378a466790d87f42e84 @utrace utrace committed with torvalds Aug 10, 2010
Showing with 5 additions and 17 deletions.
  1. +5 −17 kernel/exec_domain.c
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@@ -134,23 +134,14 @@ unregister_exec_domain(struct exec_domain *ep)
return 0;
}
-int
-__set_personality(unsigned int personality)
+int __set_personality(unsigned int personality)
{
- struct exec_domain *ep, *oep;
-
- ep = lookup_exec_domain(personality);
- if (ep == current_thread_info()->exec_domain) {
- current->personality = personality;
- module_put(ep->module);
- return 0;
- }
+ struct exec_domain *oep = current_thread_info()->exec_domain;
+ current_thread_info()->exec_domain = lookup_exec_domain(personality);
current->personality = personality;
- oep = current_thread_info()->exec_domain;
- current_thread_info()->exec_domain = ep;
-
module_put(oep->module);
+
return 0;
}
@@ -192,11 +183,8 @@ SYSCALL_DEFINE1(personality, unsigned int, personality)
{
unsigned int old = current->personality;
- if (personality != 0xffffffff) {
+ if (personality != 0xffffffff)
set_personality(personality);
- if (current->personality != personality)
- return -EINVAL;
- }
return old;
}

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