Read fault address on arm64 using proposed kernel API.
On aarch64, the top 8 bits of the address (i.e. the tag bits) of
the fault address in si_addr are always clear. This isn't ideal for
MTE which will require these bits in order to correctly diagnose
tag mismatches.
A proposed kernel patch [1] exposes the full fault address including
the tag bits as part of the ucontext. Change debuggerd to read this
fault address if available.
[1] https://patchwork.kernel.org/patch/11435077/
Bug: 135772972
Change-Id: Ia05be574113860f4e9ecc36a310c4b740e0c4afb
diff --git a/debuggerd/crash_dump.cpp b/debuggerd/crash_dump.cpp
index 087ebae..0cd2350 100644
--- a/debuggerd/crash_dump.cpp
+++ b/debuggerd/crash_dump.cpp
@@ -295,6 +295,13 @@
case 3:
process_info->abort_msg_address = crash_info->data.s.abort_msg_address;
*siginfo = crash_info->data.s.siginfo;
+ if (signal_has_si_addr(siginfo)) {
+ // Make a copy of the ucontext field because otherwise it is not aligned enough (due to
+ // being in a packed struct) and clang complains about that.
+ ucontext_t ucontext = crash_info->data.s.ucontext;
+ process_info->has_fault_address = true;
+ process_info->fault_address = get_fault_address(siginfo, &ucontext);
+ }
regs->reset(unwindstack::Regs::CreateFromUcontext(unwindstack::Regs::CurrentArch(),
&crash_info->data.s.ucontext));
break;