Messages in this thread | | | Date | Wed, 23 Aug 2017 14:55:17 +0900 | From | Sergey Senozhatsky <> | Subject | Re: possible circular locking dependency detected [was: linux-next: Tree for Aug 22] |
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On (08/23/17 13:35), Boqun Feng wrote: > > KERN_CONT and "\n" should not be together. "\n" flushes the cont > > buffer immediately. > > > > Hmm.. Not quite familiar with printk() stuffs, but I could see several > usages of printk(KERN_CONT "...\n") in kernel. > > Did a bit research myself, and I now think the inappropriate use is to > use a KERN_CONT printk *after* another printk ending with a "\n".
ah... I didn't check __print_lock_name(): it leaves unflushed cont buffer upon the return. sorry, your code is correct.
-ss
> > > printk("\n *** DEADLOCK ***\n\n"); > > > + } else if (cross_lock(src->instance)) { > > > + printk(" Possible unsafe locking scenario by crosslock:\n\n"); > > > + printk(" CPU0 CPU1\n"); > > > + printk(" ---- ----\n"); > > > + printk(" lock("); > > > + __print_lock_name(target); > > > + printk(KERN_CONT ");\n"); > > > + printk(" lock("); > > > + __print_lock_name(source); > > > + printk(KERN_CONT ");\n"); > > > + printk(" lock("); > > > + __print_lock_name(parent == source ? target : parent); > > > + printk(KERN_CONT ");\n"); > > > + printk(" unlock("); > > > + __print_lock_name(source); > > > + printk(KERN_CONT ");\n"); > > > + printk("\n *** DEADLOCK ***\n\n"); > > > } else { > > > printk(" Possible unsafe locking scenario:\n\n"); > > > printk(" CPU0 CPU1\n"); > > > -- > > > 2.14.1 > > >
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