Messages in this thread | | | Date | Mon, 14 Mar 2016 10:37:52 +0900 | From | Sergey Senozhatsky <> | Subject | Re: [PATCH v6 2/2] printk: Make printing of spin_dump() deferred to avoid a deadlock |
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On (03/11/16 19:37), Byungchul Park wrote: [..] > +static void __spin_dump_deferred(raw_spinlock_t *lock, const char *msg) > +{ > + printk_func_t s; > + > + s = this_cpu_read(printk_func); > + this_cpu_write(printk_func, vprintk_deferred); > + > + /* > + * To change printk_func, it must be in preempt disabled and irq > + * disabled. WARN_ON() should be called after the change because > + * the default printk_func which may be called from WARN_ON() > + * is prohibited in this context. > + */ > + WARN_ON(!preempt_count() || !irqs_disabled()); > + __spin_dump(lock, msg); > + > + this_cpu_write(printk_func, s); > + > + printk_pending_output(); > +} > > +static void spin_dump(raw_spinlock_t *lock, const char *msg) > +{ > + if (unlikely(console_sem_spin_is_held())) > + __spin_dump_deferred(lock, msg); > + else > + __spin_dump(lock, msg); > +}
so can it be
vprintk_emit() __spin_dump_deferred() vprintk_deferred() vprintk_emit() __spin_dump_deferred() vprintk_deferred()
or am I getting it wrong?
-ss
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