4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Max Filippov <jcmvbkbc@xxxxxxxxx> commit d90b88fd3653f1fb66ecc6571b860d5a5749fa56 upstream. 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@xxxxxxxxxxxxxxx Signed-off-by: Max Filippov <jcmvbkbc@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/xtensa/kernel/process.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -320,8 +320,8 @@ unsigned long get_wchan(struct task_stru /* 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; }
