Commit 5396b1a6 authored by Paul Burton's avatar Paul Burton Committed by Greg Kroah-Hartman

MIPS: Call dump_stack() from show_regs()

commit 5a267832c2ec47b2dad0fdb291a96bb5b8869315 upstream.

The generic nmi_cpu_backtrace() function calls show_regs() when a struct
pt_regs is available, and dump_stack() otherwise. If we were to make use
of the generic nmi_cpu_backtrace() with MIPS' current implementation of
show_regs() this would mean that we see only register data with no
accompanying stack information, in contrast with our current
implementation which calls dump_stack() regardless of whether register
state is available.

In preparation for making use of the generic nmi_cpu_backtrace() to
implement arch_trigger_cpumask_backtrace(), have our implementation of
show_regs() call dump_stack() and drop the explicit dump_stack() call in
arch_dump_stack() which is invoked by arch_trigger_cpumask_backtrace().

This will allow the output we produce to remain the same after a later
patch switches to using nmi_cpu_backtrace(). It may mean that we produce
extra stack output in other uses of show_regs(), but this:

  1) Seems harmless.
  2) Is good for consistency between arch_trigger_cpumask_backtrace()
     and other users of show_regs().
  3) Matches the behaviour of the ARM & PowerPC architectures.

Marked for stable back to v4.9 as a prerequisite of the following patch
"MIPS: Call dump_stack() from show_regs()".
Signed-off-by: default avatarPaul Burton <>
Cc: James Hogan <>
Cc: Ralf Baechle <>
Cc: Huacai Chen <>
Cc: # v4.9+
Signed-off-by: default avatarHuacai Chen <>
Signed-off-by: default avatarGreg Kroah-Hartman <>
parent 99f303b3
......@@ -637,8 +637,8 @@ static void arch_dump_stack(void *info)
if (regs)
void arch_trigger_all_cpu_backtrace(bool include_self)
......@@ -344,6 +344,7 @@ static void __show_regs(const struct pt_regs *regs)
void show_regs(struct pt_regs *regs)
__show_regs((struct pt_regs *)regs);
void show_registers(struct pt_regs *regs)
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