Messages in this thread | | | Date | Wed, 18 Jan 2017 15:12:55 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v4 15/15] lockdep: Crossrelease feature documentation |
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On Wed, Jan 18, 2017 at 09:14:59PM +0900, byungchul.park wrote:
> +Example 3: > + > + CONTEXT X CONTEXT Y > + --------- --------- > + mutex_lock A > + mutex_lock A > + mutex_unlock A > + wait_for_complete B /* DEADLOCK */
Each line (across both columns) is a distinct point in time after the line before.
Therefore, this states that "mutex_unlock A" happens before "wait_for_completion B", which is clearly impossible.
You don't have to remove everything after mutex_lock A, but the unlock must not happen before context Y does the unlock.
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