Re: [PATCH 3/4] locking/ww_mutex: Treat ww_mutex_lock() like a trylock

2021-03-18 Thread Boqun Feng
On Wed, Mar 17, 2021 at 10:54:17PM -0400, Waiman Long wrote: > On 3/17/21 10:24 PM, Boqun Feng wrote: > > Hi Waiman, > > > > Just a question out of curiosity: how does this problem hide so long? > > ;-) Because IIUC, both locktorture and ww_mutex_lock have been there for > > a while, so why

Re: [PATCH 3/4] locking/ww_mutex: Treat ww_mutex_lock() like a trylock

2021-03-17 Thread Waiman Long
On 3/17/21 10:24 PM, Boqun Feng wrote: Hi Waiman, Just a question out of curiosity: how does this problem hide so long? ;-) Because IIUC, both locktorture and ww_mutex_lock have been there for a while, so why didn't we spot this earlier? I ask just to make sure we don't introduce the problem

Re: [PATCH 3/4] locking/ww_mutex: Treat ww_mutex_lock() like a trylock

2021-03-17 Thread Boqun Feng
Hi Waiman, Just a question out of curiosity: how does this problem hide so long? ;-) Because IIUC, both locktorture and ww_mutex_lock have been there for a while, so why didn't we spot this earlier? I ask just to make sure we don't introduce the problem because of some subtle problems in

Re: [PATCH 3/4] locking/ww_mutex: Treat ww_mutex_lock() like a trylock

2021-03-16 Thread Davidlohr Bueso
On Tue, 16 Mar 2021, Waiman Long wrote: It was found that running the ww_mutex_lock-torture test produced the following lockdep splat almost immediately: [ 103.892638] == [ 103.892639] WARNING: possible circular locking dependency detected

[PATCH 3/4] locking/ww_mutex: Treat ww_mutex_lock() like a trylock

2021-03-16 Thread Waiman Long
It was found that running the ww_mutex_lock-torture test produced the following lockdep splat almost immediately: [ 103.892638] == [ 103.892639] WARNING: possible circular locking dependency detected [ 103.892641] 5.12.0-rc3-debug+ #2