xtensa: fix get_wchan

Stack unwinding is implemented incorrectly in xtensa get_wchan: instead of extracting a0 and a1 registers from the spill location under the stack pointer it extracts a word pointed to by the stack pointer and subtracts 4 or 3 from it. Cc: [email protected] Signed-off-by: Max Filippov <[email protected]>
brucespang · Feb 7, 2019 · d90b88f · d90b88f
1 parent 579afe8
commit d90b88f
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c
@@ -321,8 +321,8 @@ unsigned long get_wchan(struct task_struct *p)
 
 		/* Stack layout: sp-4: ra, sp-3: sp' */
 
-		pc = MAKE_PC_FROM_RA(*(unsigned long*)sp - 4, sp);
-		sp = *(unsigned long *)sp - 3;
+		pc = MAKE_PC_FROM_RA(SPILL_SLOT(sp, 0), sp);
+		sp = SPILL_SLOT(sp, 1);
 	} while (count++ < 16);
 	return 0;
 }