On Tue, 27 Mar 2018, Tetsuo Handa wrote:
> Since "struct lockdep_map" is embedded into lock objects, we can know
> which instance of a lock object is acquired using hlock->instance field.
> This will help finding which threads are causing a lock contention.
>
> Currently, print_lock() is printing hlock->acquire_ip field in both
> "[<%px>]" and "%pS" format. But "[<%px>]" is little useful nowadays, for
> we use scripts/faddr2line which receives "%pS" for finding the location
> in the source code. And I want to reduce amount of output, for
> debug_show_all_locks() might print a lot.
>
> Therefore, this patch replaces "[<%px>]" for printing hlock->acquire_ip
> field with "%p" for printing hlock->instance field.
>
> [ 251.305475] 3 locks held by a.out/31106:
> [ 251.308949] #0: 00000000b0f753ba (&mm->mmap_sem){++++}, at: copy_process.part.41+0x10d5/0x1fe0
> [ 251.314283] #1: 00000000ef64d539 (&mm->mmap_sem/1){+.+.}, at: copy_process.part.41+0x10fe/0x1fe0
> [ 251.319618] #2: 00000000b41a282e (&mapping->i_mmap_rwsem){++++}, at: copy_process.part.41+0x12f2/0x1fe0
>
> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: David Rientjes <rientjes@xxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
