https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114
Bug ID: 100114
Summary: libasan built against latest glibc doesn't work
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: sanitizer
Assignee: unassigned at gcc dot gnu.org
Reporter: jakub at gcc dot gnu.org
CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at
gcc dot gnu.org
Target Milestone: ---
If libsanitizer is built against glibc trunk, nothing really works:
./a
==91==ERROR: AddressSanitizer failed to allocate 0x0 (0) bytes of
SetAlternateSignalStack (error code: 22)
==91==Process memory map follows:
I think this is caused by
// TODO(glider): different tools may require different altstack size.
static const uptr kAltStackSize = SIGSTKSZ * 4; // SIGSTKSZ is not enough.
void SetAlternateSignalStack() {
stack_t altstack, oldstack;
CHECK_EQ(0, sigaltstack(nullptr, &oldstack));
// If the alternate stack is already in place, do nothing.
// Android always sets an alternate stack, but it's too small for us.
if (!SANITIZER_ANDROID && !(oldstack.ss_flags & SS_DISABLE)) return;
// TODO(glider): the mapped stack should have the MAP_STACK flag in the
// future. It is not required by man 2 sigaltstack now (they're using
// malloc()).
void* base = MmapOrDie(kAltStackSize, __func__);
altstack.ss_sp = (char*) base;
altstack.ss_flags = 0;
altstack.ss_size = kAltStackSize;
CHECK_EQ(0, sigaltstack(&altstack, nullptr));
}
called from
#0 0x00007ffff7644650 in sigaltstack () from ./libasan.so.6
#1 0x00007ffff76bca92 in __sanitizer::SetAlternateSignalStack() () from
./libasan.so.6
#2 0x00007ffff76bcc65 in __sanitizer::InstallDeadlySignalHandlers(void
(*)(int, void*, void*)) () from ./libasan.so.6
#3 0x00007ffff76ab60c in __asan::AsanInitInternal() [clone .part.0] () from
./libasan.so.6
#4 0x00007ffff7fdb6ee in _dl_init () from /lib64/ld-linux-x86-64.so.2
#5 0x00007ffff7fcc0ca in _dl_start_user () from /lib64/ld-linux-x86-64.so.2
and __asan_init which tail calls AsanInitInternal is registered in
.preinit_array.
As in newer glibcs SIGSTKSZ is no longer a constant - since
https://sourceware.org/git/?p=glibc.git;a=commit;h=6c57d320484988e87e446e2e60ce42816bf51d53
- I think the above is invalid C++, because the function is called before the
kAltStackSize variable is constructed (which is why we end up with calling
MmapOrDie(0, __func__);
and that fails miserably.
