On 02/21/2018 05:55 PM, Ram Pai wrote: > From: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx> > > The sig_chld() handler calls dprintf2() taking care of setting > dprint_in_signal so that sigsafe_printf() won't call printf(). > Unfortunately, this precaution is is negated by dprintf_level(), which > has a call to fflush(). > > This function acquires a lock, which means that if the signal interrupts an > ongoing fflush() the process will deadlock. At least on powerpc this is > easy to trigger, resulting in the following backtrace when attaching to the > frozen process: Ugh, yeah, I've run into this too. Acked-by: Dave Hansen <dave.hansen@xxxxxxxxx>
