================
@@ -2762,18 +2757,17 @@ int UnwindCursor<A,
R>::stepThroughSigReturn(Registers_arm64 &) {
template <typename A, typename R>
bool UnwindCursor<A, R>::setInfoForSigReturn(Registers_riscv &) {
const pint_t pc = static_cast<pint_t>(getReg(UNW_REG_IP));
- uint32_t instructions[2];
- struct iovec local_iov = {&instructions, sizeof instructions};
- struct iovec remote_iov = {reinterpret_cast<void *>(pc), sizeof
instructions};
- long bytesRead =
- syscall(SYS_process_vm_readv, getpid(), &local_iov, 1, &remote_iov, 1,
0);
+ // The PC might contain an invalid address if the unwind info is bad, so
+ // directly accessing it could cause a SIGSEGV.
+ if (!isReadableAddr(pc) || !isReadableAddr(pc + 4))
----------------
MaskRay wrote:
It is unfortunate that we have to call `isReadableAddr` twice.
`linux/kernel/signal.c` `rt_sigprocmask` actually supports an unaligned
address. We can remove the alignment code `const auto alignedAddr = addr &
~pint_t{7};` and use one `isReadableAddr(pc)`
https://github.com/llvm/llvm-project/pull/74791
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