From f4988f5bd4176345aad2a525e24d5fd11b3c97ea Mon Sep 17 00:00:00 2001 From: Saleem Abdulrasool Date: Thu, 30 Jun 2022 15:34:32 -0700 Subject: debugging: account for differences in alternate signal stacks The alternate signal stack may be sufficiently beyond the esimated frame size (100k). If we run into the case that the frame is not in the correct direction assume that the frames may be non-contiguous due to an alternate signal stack layout. In such a case, if we find that there is an alternate stack configured, ignore the discontiuity (assuming that it is a removable point-wise discontinuity) and continue the stack unwinding. This permits us to capture stack traces in more cases. PiperOrigin-RevId: 458327775 Change-Id: Ia8b461847401492f72a23ba26601c72e0109402c --- absl/debugging/internal/stacktrace_riscv-inl.inc | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'absl/debugging/internal/stacktrace_riscv-inl.inc') diff --git a/absl/debugging/internal/stacktrace_riscv-inl.inc b/absl/debugging/internal/stacktrace_riscv-inl.inc index 7123b71b..ba0775b2 100644 --- a/absl/debugging/internal/stacktrace_riscv-inl.inc +++ b/absl/debugging/internal/stacktrace_riscv-inl.inc @@ -159,6 +159,21 @@ static void ** NextStackFrame(void **old_frame_pointer, const void *uc) { const uintptr_t max_size = STRICT_UNWINDING ? 100000 : 1000000; const uintptr_t frame_size = ComputeStackFrameSize(old_frame_pointer, new_frame_pointer); + + // If we have a alternate signal stack, the stack pointer may not be + // contiguous. In such a case, we can simply skip the check and assume that + // the non-contiguity is permissible. + if (frame_size == kUnknownFrameSize) { + assert(old_frame_pointer >= new_frame_pointer); + + stack_t ss{}; + if (sigaltstack(nullptr, &ss) == 0) { + if (ss.ss_flags & SS_DISABLE) + return nullptr; + return new_frame_pointer; + } + } + if (frame_size == kUnknownFrameSize || frame_size > max_size) return nullptr; } -- cgit v1.2.3