Messages in this thread | | | Date | Mon, 12 Dec 2016 17:30:18 +0100 | From | Petr Mladek <> | Subject | Re: [RFC][PATCHv5 6/7] printk: use printk_safe buffers in printk |
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On Thu 2016-12-01 22:55:45, Sergey Senozhatsky wrote: > Use printk_safe per-CPU buffers in printk recursion-prone blocks: > -- around logbuf_lock protected sections in vprintk_emit() and > console_unlock() > -- around down_trylock_console_sem() and up_console_sem() > > Note that this solution addresses deadlocks caused by printk() > recursive calls only. That is vprintk_emit() and console_unlock(). > > Another thing to note is that we now keep lockdep enabled in printk, > because we are protected against the printk recursion caused by lockdep > in vprintk_emit() by the printk-safe mechanism - we first switch to > per-CPU buffers and only then access the deadlock-prone locks. > > Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Looks fine and safe to me.
Reviewed-by: Petr Mladek <pmladek@suse.com>
Best Regards, Petr
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