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Systems which don't provide arch_trigger_cpumask_backtrace() will invoke showacpu() from a smp_call_function() function which is invoked with disabled interrupts even on -RT systems. The function acquires the show_lock lock which only purpose is to ensure that the CPUs don't print simultaneously. Otherwise the output would clash and it would be hard to tell the output from CPUx apart from CPUy. On -RT the spin_lock() can not be acquired from this context. A raw_spin_lock() is required. It will introduce the system's latency by performing the sysrq request and other CPUs will block on the lock until the request is done. This is okay because the user asked for a backtrace of all active CPUs and under "normal circumstances in production" this path should not be triggered. Signed-off-by: Julien Grall <julien.grall@arm.com> [bigeasy@linuxtronix.de: commit description] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| .. | ||
| hvc | ||
| ipwireless | ||
| serdev | ||
| serial | ||
| vt | ||
| amiserial.c | ||
| cyclades.c | ||
| ehv_bytechan.c | ||
| goldfish.c | ||
| isicom.c | ||
| Kconfig | ||
| Makefile | ||
| mips_ejtag_fdc.c | ||
| moxa.c | ||
| moxa.h | ||
| mxser.c | ||
| mxser.h | ||
| n_gsm.c | ||
| n_hdlc.c | ||
| n_null.c | ||
| n_r3964.c | ||
| n_tracerouter.c | ||
| n_tracesink.c | ||
| n_tracesink.h | ||
| n_tty.c | ||
| nozomi.c | ||
| pty.c | ||
| rocket_int.h | ||
| rocket.c | ||
| rocket.h | ||
| synclink_gt.c | ||
| synclink.c | ||
| synclinkmp.c | ||
| sysrq.c | ||
| tty_audit.c | ||
| tty_baudrate.c | ||
| tty_buffer.c | ||
| tty_io.c | ||
| tty_ioctl.c | ||
| tty_jobctrl.c | ||
| tty_ldisc.c | ||
| tty_ldsem.c | ||
| tty_mutex.c | ||
| tty_port.c | ||
| vcc.c | ||