From dc370a82467cb35066475537b797197aee3e5164 Mon Sep 17 00:00:00 2001 From: Saleem Abdulrasool Date: Fri, 29 Jul 2022 14:38:13 -0700 Subject: debugging: honour `STRICT_UNWINDING` in RISCV path The changes in d6f96eda14aca77748a439f05a567a46ce87e462 enabled handling cases where the stack may be non-contiguous or not fully symbolicated (e.g. in cases of alternate signal stacks). However, it did not properly honour the requests from the caller to perform a strict unwinding where such frames are terminated upon the discontinuity. This repairs that condition. Hoist the alignment check since that is safe to perform early. PiperOrigin-RevId: 464160529 Change-Id: Ic65645928ec60c2a3b4844f3abd4fed1b991edab --- absl/debugging/internal/stacktrace_riscv-inl.inc | 40 ++++++++++++------------ 1 file changed, 20 insertions(+), 20 deletions(-) (limited to 'absl/debugging') diff --git a/absl/debugging/internal/stacktrace_riscv-inl.inc b/absl/debugging/internal/stacktrace_riscv-inl.inc index 70b11e5e..a0f23739 100644 --- a/absl/debugging/internal/stacktrace_riscv-inl.inc +++ b/absl/debugging/internal/stacktrace_riscv-inl.inc @@ -115,7 +115,13 @@ static void ** NextStackFrame(void **old_frame_pointer, const void *uc, // $sp ->| ... | // +----------------+ void **new_frame_pointer = reinterpret_cast(old_frame_pointer[-2]); - bool check_frame_size = true; + + // The RISCV ELF psABI mandates that the stack pointer is always 16-byte + // aligned. + // TODO(#1236) this doesn't hold for ILP32E which only mandates a 4-byte + // alignment. + if ((reinterpret_cast(new_frame_pointer) & 15) != 0) + return nullptr; #if defined(__linux__) if (WITH_CONTEXT && uc != nullptr) { @@ -139,34 +145,28 @@ static void ** NextStackFrame(void **old_frame_pointer, const void *uc, // Alleged frame pointer is readable, use it for further unwinding. new_frame_pointer = pre_signal_frame_pointer; - - // Skip frame size check if we return from a signal. We may be using an - // alterate stack for signals. - check_frame_size = false; } + return new_frame_pointer; } #endif - // The RISCV ELF psABI mandates that the stack pointer is always 16-byte - // aligned. - // FIXME(abdulras) this doesn't hold for ILP32E which only mandates a 4-byte - // alignment. - if ((reinterpret_cast(new_frame_pointer) & 15) != 0) - return nullptr; - // Check frame size. In strict mode, we assume frames to be under 100,000 // bytes. In non-strict mode, we relax the limit to 1MB. - if (check_frame_size) { - const uintptr_t max_size = STRICT_UNWINDING ? 100000 : 1000000; - const uintptr_t frame_size = - ComputeStackFrameSize(old_frame_pointer, new_frame_pointer); - if (frame_size == kUnknownFrameSize && - (reinterpret_cast(new_frame_pointer) < range.first || - reinterpret_cast(new_frame_pointer) > range.second)) + const uintptr_t max_size = STRICT_UNWINDING ? 100000 : 1000000; + const uintptr_t frame_size = + ComputeStackFrameSize(old_frame_pointer, new_frame_pointer); + if (frame_size == kUnknownFrameSize) { + if (STRICT_UNWINDING) return nullptr; - if (frame_size > max_size) + + // In non-strict mode permit non-contiguous stacks (e.g. alternate signal + // frame handling). + if (reinterpret_cast(new_frame_pointer) < range.first || + reinterpret_cast(new_frame_pointer) > range.second) return nullptr; } + if (frame_size > max_size) + return nullptr; return new_frame_pointer; } -- cgit v1.2.3