On Wed, 21 May 2014, Borislav Petkov wrote: > > Why is it a problem if user_mode_vm(regs)? Conversely, why is sending > > a signal a remotely reasonable thing to do if !user_mode_vm(regs)? > > Let me quote Jiri: > > (1) task sends signal to itself > (2) it acquires sighand->siglock so that it's able to queue the signal > (3) MCE triggers > (4) it tries to send a signal to the same task > (5) it tries to acquire sighand->siglock and loops forever
Ah, alright, but due to what mce_severity() does, this can't happen, because if the current CPU is in the kernel (which is obviously implied by holding a spinlock), it never proceeds sending the signal, becase no_way_out gets set and mce_panic() invoked. -- Jiri Kosina SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
