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author | David Howells <dhowells@redhat.com> | 2010-07-29 12:45:55 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-07-29 15:16:18 -0700 |
commit | 8f92054e7ca1d3a3ae50fb42d2253ac8730d9b2a (patch) | |
tree | 29d1bcf78bf04fe41c7e811f806f58d655c41f9f /Documentation/credentials.txt | |
parent | de09a9771a5346029f4d11e4ac886be7f9bfdd75 (diff) | |
download | linux-stable-8f92054e7ca1d3a3ae50fb42d2253ac8730d9b2a.tar.gz linux-stable-8f92054e7ca1d3a3ae50fb42d2253ac8730d9b2a.tar.bz2 linux-stable-8f92054e7ca1d3a3ae50fb42d2253ac8730d9b2a.zip |
CRED: Fix __task_cred()'s lockdep check and banner comment
Fix __task_cred()'s lockdep check by removing the following validation
condition:
lockdep_tasklist_lock_is_held()
as commit_creds() does not take the tasklist_lock, and nor do most of the
functions that call it, so this check is pointless and it can prevent
detection of the RCU lock not being held if the tasklist_lock is held.
Instead, add the following validation condition:
task->exit_state >= 0
to permit the access if the target task is dead and therefore unable to change
its own credentials.
Fix __task_cred()'s comment to:
(1) discard the bit that says that the caller must prevent the target task
from being deleted. That shouldn't need saying.
(2) Add a comment indicating the result of __task_cred() should not be passed
directly to get_cred(), but rather than get_task_cred() should be used
instead.
Also put a note into the documentation to enforce this point there too.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/credentials.txt')
-rw-r--r-- | Documentation/credentials.txt | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/credentials.txt b/Documentation/credentials.txt index a2db35287003..995baf379c07 100644 --- a/Documentation/credentials.txt +++ b/Documentation/credentials.txt @@ -417,6 +417,9 @@ reference on them using: This does all the RCU magic inside of it. The caller must call put_cred() on the credentials so obtained when they're finished with. + [*] Note: The result of __task_cred() should not be passed directly to + get_cred() as this may race with commit_cred(). + There are a couple of convenience functions to access bits of another task's credentials, hiding the RCU magic from the caller: |