Re: [PATCH] AB-BA deadlock between uidhash_lock and tasklist_lock.

From: Linus Torvalds
Date: Thu Mar 10 2005 - 14:01:42 EST

On Thu, 10 Mar 2005, Robin Holt wrote:
> reparent_to_init() does write_lock_irq(&tasklist_lock) then calls
> switch_uid() which calls free_uid() which grabs the uidhash_lock.
> Independent of that, we have seen a different cpu call free_uid as a
> result of sys_wait4 and, immediately after acquiring the uidhash_lock,
> receive a timer interrupt which eventually leads to an attempt to grab
> the tasklist_lock.

Hmm.. We fixed this already, and the current tree doesn't have this
problem (and the fix was much simpler: just move "switch_uid()" to outside
the tasklist_lock.

That fix was done late december last year (current BK revision:
1.1938.446.38), and I really think your patch is stale. Please

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