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futex: additional (get|put)_futex_key() fixes

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Impact: fix races

futex_requeue and futex_lock_pi still had some bad
(get|put)_futex_key() usage. This patch adds the missing
put_futex_keys() and corrects a goto in futex_lock_pi() to avoid
a double get.

Build and boot tested on a 4 way Intel x86_64 workstation.
Passes basic pthread_mutex and PI tests out of
ltp/testcases/realtime.

Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <20090312075545.9856.75152.stgit@Aeon>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Darren Hart 2009-03-12 00:55:46 -07:00 committed by Ingo Molnar
parent b2d0994b13
commit de87fcc124
1 changed files with 11 additions and 5 deletions
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16
kernel/futex.c
View file

@ -802,8 +802,10 @@ futex_wake_op(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
ret = get_user(dummy, uaddr2);
if (ret)
return ret;
goto out_put_keys;
put_futex_key(fshared, &key2);
put_futex_key(fshared, &key1);
goto retryfull;
}
@ -878,6 +880,9 @@ static int futex_requeue(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
if (hb1 != hb2)
spin_unlock(&hb2->lock);
put_futex_key(fshared, &key2);
put_futex_key(fshared, &key1);
ret = get_user(curval, uaddr1);
if (!ret)
@ -1453,6 +1458,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
* exit to complete.
*/
queue_unlock(&q, hb);
put_futex_key(fshared, &q.key);
cond_resched();
goto retry;
@ -1595,13 +1601,12 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
ret = get_user(uval, uaddr);
if (!ret)
goto retry;
goto retry_unlocked;
if (to)
destroy_hrtimer_on_stack(&to->timer);
return ret;
goto out_put_key;
}
/*
* Userspace attempted a TID -> 0 atomic transition, and failed.
* This is the in-kernel slowpath: we look up the PI state (if any),
@ -1705,6 +1710,7 @@ static int futex_unlock_pi(u32 __user *uaddr, int fshared)
}
ret = get_user(uval, uaddr);
put_futex_key(fshared, &key);
if (!ret)
goto retry;