linux/include
Oleg Nesterov 43e13cc107 cred: remove task_is_dead() from __task_cred() validation
Commit 8f92054e7c ("CRED: Fix __task_cred()'s lockdep check and banner
comment"):

    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.

OK, but afaics currently this can only help wait_task_zombie() which calls
__task_cred() without rcu lock.

Remove this validation and change wait_task_zombie() to use task_uid()
instead.  This means we do rcu_read_lock() only to shut up the lockdep,
but we already do the same in, say, wait_task_stopped().

task_is_dead() should die, task->exit_state != 0 means that this task has
passed exit_notify(), only do_wait-like code paths should use this.

Unfortunately, we can't kill task_is_dead() right now, it has already
acquired buggy users in drivers/staging.  The fix already exists.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:28 -07:00
..
acpi ACPI: Add _PLD support 2012-05-11 17:03:12 -07:00
asm-generic vsprintf: further optimize decimal conversion 2012-05-31 17:49:27 -07:00
crypto
drm introduce SIZE_MAX 2012-05-31 17:49:26 -07:00
keys KEYS: Permit in-place link replacement in keyring list 2012-05-11 10:56:56 +01:00
linux cred: remove task_is_dead() from __task_cred() validation 2012-05-31 17:49:28 -07:00
math-emu
media [media] patch for Asus My Cinema PS3-100 (1043:48cd) 2012-05-20 16:05:02 -03:00
memory
misc
mtd UBI: amend commentaries WRT dtype 2012-05-20 20:25:59 +03:00
net memcg: decrement static keys at real destroy time 2012-05-29 16:22:28 -07:00
pcmcia
rdma Merge branches 'core', 'cxgb4', 'ipath', 'iser', 'lockdep', 'mlx4', 'nes', 'ocrdma', 'qib' and 'raw-qp' into for-linus 2012-05-21 09:00:47 -07:00
rxrpc
scsi isci update for 3.5 2012-05-21 12:17:30 +01:00
sound ASoC: Last minute updates 2012-05-22 02:58:55 +02:00
target target: Add MI_REPORT_TARGET_PGS ext. header + implict_trans_secs attribute 2012-05-17 00:45:58 -07:00
trace mm: vmscan: remove reclaim_mode_t 2012-05-29 16:22:19 -07:00
video arm-soc: First batch of cleanups 2012-05-22 09:23:24 -07:00
xen xen: do not map the same GSI twice in PVHVM guests. 2012-05-21 14:11:36 -04:00
Kbuild