From: Matt Redfearn <[email protected]>

Within unwind stack, check if the stack pointer being unwound is within
the CPU's irq_stack and if so use that page rather than the task's stack
page.

Signed-off-by: Matt Redfearn <[email protected]>
Acked-by: Jason A. Donenfeld <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Adam Buchbinder <[email protected]>
Cc: Maciej W. Rozycki <[email protected]>
Cc: Marcin Nowakowski <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: James Hogan <[email protected]>
Cc: Paul Burton <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: [email protected]
Cc: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/14741/
Signed-off-by: Ralf Baechle <[email protected]>
(cherry picked from commit d42d8d106b0275b027c1e8992c42aecf933436ea)
Signed-off-by: Amit Pundir <[email protected]>
---
 arch/mips/kernel/process.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 7d80447..efa1df5 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -33,6 +33,7 @@
 #include <asm/dsemul.h>
 #include <asm/dsp.h>
 #include <asm/fpu.h>
+#include <asm/irq.h>
 #include <asm/msa.h>
 #include <asm/pgtable.h>
 #include <asm/mipsregs.h>
@@ -556,7 +557,19 @@ EXPORT_SYMBOL(unwind_stack_by_address);
 unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
                           unsigned long pc, unsigned long *ra)
 {
-       unsigned long stack_page = (unsigned long)task_stack_page(task);
+       unsigned long stack_page = 0;
+       int cpu;
+
+       for_each_possible_cpu(cpu) {
+               if (on_irq_stack(cpu, *sp)) {
+                       stack_page = (unsigned long)irq_stack[cpu];
+                       break;
+               }
+       }
+
+       if (!stack_page)
+               stack_page = (unsigned long)task_stack_page(task);
+
        return unwind_stack_by_address(stack_page, sp, pc, ra);
 }
 #endif
-- 
2.7.4

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