Messages in this thread | | | Date | Tue, 22 Sep 2015 12:59:00 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH v3] arm: Fix backtrace generation when IPI is masked |
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On Tue, 15 Sep 2015, Daniel Thompson wrote:
> Currently on ARM when <SysRq-L> is triggered from an interrupt handler > (e.g. a SysRq issued using UART or kbd) the main CPU will wedge for ten > seconds with interrupts masked before issuing a backtrace for every CPU > except itself. > > The new backtrace code introduced by commit 96f0e00378d4 ("ARM: add > basic support for on-demand backtrace of other CPUs") does not work > correctly when run from an interrupt handler because IPI_CPU_BACKTRACE > is used to generate the backtrace on all CPUs but cannot preempt the > current calling context. > > This can be fixed by detecting that the calling context cannot be > preempted and issuing the backtrace directly in this case. Issuing > directly leaves us without any pt_regs to pass to nmi_cpu_backtrace() > so we also modify the generic code to call dump_stack() when its > argument is NULL. > > Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
For the genric part.
Acked-by: Thomas Gleixner <tglx@linutronix.de>
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