commit 35619cf07e66f2d667c114d57ea19afdc1ad839a
author Jerome Forissier <jerome@forissier.org> Mon Jun 22 11:28:32 2020 +0200
committer Jérôme Forissier <jerome@forissier.org> Mon Jun 22 17:04:34 2020 +0200
tree a34263f9992ffdbb413233beed421c9c881e69e5
parent 35e770df71a8c35d6c3006e25939d936dca02bbc

ldelf: arm64: do not unwind past end of stack

unwind_arm64() currently does not check the value of the frame pointer
after it has done its job unwinding one frame. A NULL value indicates
the end of the call stack, and therefore the function should return
false to stop the caller from unwinding further (a do .. while loop is
used in print_stack_arm64()). Instead invalid values for FP and PC are
returned which causes an erroneous display and the unwind stops one
step too late, when the FP is found to be outside the stack.

Fixes the invalid last line in call stacks such as xtest 1019:

 E/TC:? 0 TA panicked with code 0x0
 E/LD:  Status of TA 5b9e0e40-2636-11e1-ad9e-0002a5d5c51b
 E/LD:   arch: aarch64
 [...]
 E/LD:  Call stack:
 E/LD:   0x0000000080062a50
 E/LD:   0x00000000801df848
 E/LD:   0x00000000800631a8
 E/LD:   0xfffffffffffffffc

Signed-off-by: Jerome Forissier <jerome@forissier.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>