Commit d90b88fd authored Jan 02, 2019 by Max Filippov

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: stable@vger.kernel.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

parent 579afe86

arch/xtensa/kernel/process.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}

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