On Thu, Mar 29, 2018 at 07:26:52PM +0900, Tetsuo Handa wrote: > >From 91c081c4c5f6a99402542951e7de661c38f928ab Mon Sep 17 00:00:00 2001 > From: Tetsuo Handa <[email protected]> > Date: Tue, 27 Mar 2018 19:38:33 +0900 > Subject: [PATCH v2] lockdep: Show address of "struct lockdep_map" at > print_lock(). > > 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 <[email protected]> > Acked-by: Michal Hocko <[email protected]> > Acked-by: David Rientjes <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]> Ingo, can you merge this? > Cc: Ingo Molnar <[email protected]> > Cc: Borislav Petkov <[email protected]> > Cc: Thomas Gleixner <[email protected]> > --- > kernel/locking/lockdep.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c > index 12a2805..0233863 100644 > --- a/kernel/locking/lockdep.c > +++ b/kernel/locking/lockdep.c > @@ -556,9 +556,9 @@ static void print_lock(struct held_lock *hlock) > return; > } > > + printk(KERN_CONT "%p", hlock->instance); > print_lock_name(lock_classes + class_idx - 1); > - printk(KERN_CONT ", at: [<%px>] %pS\n", > - (void *)hlock->acquire_ip, (void *)hlock->acquire_ip); > + printk(KERN_CONT ", at: %pS\n", (void *)hlock->acquire_ip); > } > > static void lockdep_print_held_locks(struct task_struct *curr) > -- > 1.8.3.1 >
