diff options
author | Vitaly Buka <vitalybuka@google.com> | 2017-09-13 00:24:44 +0000 |
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committer | Vitaly Buka <vitalybuka@google.com> | 2017-09-13 00:24:44 +0000 |
commit | cad7a086bf3ecc2d9cb1e79cfb299fe923a53c8e (patch) | |
tree | 6036ca5f83ace7a099e98b24604d2e30f0ce39fb /lib/sanitizer_common/sanitizer_posix_libcdep.cc | |
parent | 284242005b49b997d8528f25b9c0eb823a9d7747 (diff) |
[compiler-rt] Move IsStackOverflow into sanitizer_posix_libcdep.cc to the rest
of instrumentation code.
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@313100 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/sanitizer_common/sanitizer_posix_libcdep.cc')
-rw-r--r-- | lib/sanitizer_common/sanitizer_posix_libcdep.cc | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/lib/sanitizer_common/sanitizer_posix_libcdep.cc b/lib/sanitizer_common/sanitizer_posix_libcdep.cc index 13062f000..5ff71b4e2 100644 --- a/lib/sanitizer_common/sanitizer_posix_libcdep.cc +++ b/lib/sanitizer_common/sanitizer_posix_libcdep.cc @@ -215,6 +215,51 @@ void InstallDeadlySignalHandlers(SignalHandlerType handler) { MaybeInstallSigaction(SIGFPE, handler); MaybeInstallSigaction(SIGILL, handler); } +bool IsStackOverflow(int code, const SignalContext &sig) { + // Access at a reasonable offset above SP, or slightly below it (to account + // for x86_64 or PowerPC redzone, ARM push of multiple registers, etc) is + // probably a stack overflow. +#ifdef __s390__ + // On s390, the fault address in siginfo points to start of the page, not + // to the precise word that was accessed. Mask off the low bits of sp to + // take it into account. + bool IsStackAccess = + sig.addr >= (sig.sp & ~0xFFF) && sig.addr < sig.sp + 0xFFFF; +#else + bool IsStackAccess = sig.addr + 512 > sig.sp && sig.addr < sig.sp + 0xFFFF; +#endif + +#if __powerpc__ + // Large stack frames can be allocated with e.g. + // lis r0,-10000 + // stdux r1,r1,r0 # store sp to [sp-10000] and update sp by -10000 + // If the store faults then sp will not have been updated, so test above + // will not work, because the fault address will be more than just "slightly" + // below sp. + if (!IsStackAccess && IsAccessibleMemoryRange(sig.pc, 4)) { + u32 inst = *(unsigned *)sig.pc; + u32 ra = (inst >> 16) & 0x1F; + u32 opcd = inst >> 26; + u32 xo = (inst >> 1) & 0x3FF; + // Check for store-with-update to sp. The instructions we accept are: + // stbu rs,d(ra) stbux rs,ra,rb + // sthu rs,d(ra) sthux rs,ra,rb + // stwu rs,d(ra) stwux rs,ra,rb + // stdu rs,ds(ra) stdux rs,ra,rb + // where ra is r1 (the stack pointer). + if (ra == 1 && + (opcd == 39 || opcd == 45 || opcd == 37 || opcd == 62 || + (opcd == 31 && (xo == 247 || xo == 439 || xo == 183 || xo == 181)))) + IsStackAccess = true; + } +#endif // __powerpc__ + + // We also check si_code to filter out SEGV caused by something else other + // then hitting the guard page or unmapped memory, like, for example, + // unaligned memory access. + return IsStackAccess && (code == si_SEGV_MAPERR || code == si_SEGV_ACCERR); +} + #endif // SANITIZER_GO bool IsAccessibleMemoryRange(uptr beg, uptr size) { |