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powerpc: handle kdump appropriately with crash_kexec_post_notifiers option

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Kdump can be triggered after panic_notifers since commit f06e5153f4
("kernel/panic.c: add "crash_kexec_post_notifiers" option for kdump
after panic_notifers") introduced crash_kexec_post_notifiers option.
But using this option would mean smp_send_stop(), that marks all other
CPUs as offline, gets called before kdump is triggered. As a result,
kdump routines fail to save other CPUs' registers. To fix this, kdump
friendly crash_smp_send_stop() function was introduced with kernel
commit 0ee59413c9 ("x86/panic: replace smp_send_stop() with kdump
friendly version in panic path"). Override this kdump friendly weak
function to handle crash_kexec_post_notifiers option appropriately
on powerpc.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
[Fixed signature of crash_stop_this_cpu() - reported by lkp@intel.com]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211207103719.91117-1-hbathini@linux.ibm.com
This commit is contained in:
Hari Bathini 2021-12-07 16:07:18 +05:30 committed by Michael Ellerman
parent 3c42e95420
commit 219572d2fc
1 changed files with 30 additions and 0 deletions
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30
arch/powerpc/kernel/smp.c
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@ -620,6 +620,36 @@ void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
}
#endif
#ifdef CONFIG_NMI_IPI
static void crash_stop_this_cpu(struct pt_regs *regs)
#else
static void crash_stop_this_cpu(void *dummy)
#endif
{
/*
* Just busy wait here and avoid marking CPU as offline to ensure
* register data is captured appropriately.
*/
while (1)
cpu_relax();
}
void crash_smp_send_stop(void)
{
static bool stopped = false;
if (stopped)
return;
stopped = true;
#ifdef CONFIG_NMI_IPI
smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, crash_stop_this_cpu, 1000000);
#else
smp_call_function(crash_stop_this_cpu, NULL, 0);
#endif /* CONFIG_NMI_IPI */
}
#ifdef CONFIG_NMI_IPI
static void nmi_stop_this_cpu(struct pt_regs *regs)
{