[compiler-rt] r189753 - [sanitizer_common] Add internal_clone().
Sergey Matveev
earthdok at google.com
Tue Oct 8 09:42:04 PDT 2013
Fixed in r192196
On Tue, Oct 8, 2013 at 8:29 PM, Sergey Matveev <earthdok at google.com> wrote:
> Apparently .cfi_undefined is not supported by clang 3.2. We only need the
> CFI stuff when using the slow unwinder from under StopTheWorld (i.e. if
> there's a crash in a StopTheWorld callback and we want to get the
> backtrace). So the worst thing that can happen if we remove this line is us
> not being able to get the backtrace to an internal crash. That said, I
> tried removing all CFI directives from this function and it looks like the
> unwinder still works, so I'll probably leave it at that.
>
>
> On Sat, Oct 5, 2013 at 12:07 AM, Matt Arsenault <Matthew.Arsenault at amd.com
> > wrote:
>
>> This has been breaking the build for me for a while (I'm using the
>> packaged clang 3.2 on Ubuntu 13.04):
>>
>> /home/marsenau/src/llvm/**projects/compiler-rt/lib/**
>> sanitizer_common/sanitizer_**linux.cc:801:25: error: unknown directive
>> ".cfi_undefined %%rip;\n"
>> ^
>> <inline asm>:8:1: note: instantiated into assembly here
>> .cfi_undefined %rip;
>> ^
>> [ 14%] 1 error generated.
>>
>>
>>
>> On 09/02/2013 04:36 AM, Sergey Matveev wrote:
>>
>>> Author: smatveev
>>> Date: Mon Sep 2 06:36:19 2013
>>> New Revision: 189753
>>>
>>> URL: http://llvm.org/viewvc/llvm-**project?rev=189753&view=rev<http://llvm.org/viewvc/llvm-project?rev=189753&view=rev>
>>> Log:
>>> [sanitizer_common] Add internal_clone().
>>>
>>> Add a wrapper for the clone syscall for use in StopTheWorld. We
>>> implement it only for x86_64, so stop building StopTheWorld for other
>>> platforms
>>> (no one uses it outside x86_64 anyway).
>>>
>>> See https://code.google.com/p/**address-sanitizer/issues/**detail?id=214<https://code.google.com/p/address-sanitizer/issues/detail?id=214>for why we
>>> can't use the glibc clone() wrapper.
>>>
>>> Modified:
>>> compiler-rt/trunk/lib/**sanitizer_common/sanitizer_**linux.cc
>>> compiler-rt/trunk/lib/**sanitizer_common/sanitizer_**linux.h
>>> compiler-rt/trunk/lib/**sanitizer_common/sanitizer_**
>>> stoptheworld_linux_libcdep.cc
>>> compiler-rt/trunk/lib/**sanitizer_common/tests/**
>>> sanitizer_stoptheworld_test.cc
>>>
>>> Modified: compiler-rt/trunk/lib/**sanitizer_common/sanitizer_**linux.cc
>>> URL: http://llvm.org/viewvc/llvm-**project/compiler-rt/trunk/lib/**
>>> sanitizer_common/sanitizer_**linux.cc?rev=189753&r1=189752&**
>>> r2=189753&view=diff<http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc?rev=189753&r1=189752&r2=189753&view=diff>
>>> ==============================**==============================**
>>> ==================
>>> --- compiler-rt/trunk/lib/**sanitizer_common/sanitizer_**linux.cc
>>> (original)
>>> +++ compiler-rt/trunk/lib/**sanitizer_common/sanitizer_**linux.cc Mon
>>> Sep 2 06:36:19 2013
>>> @@ -679,6 +679,69 @@ void ForEachMappedRegion(link_map *map,
>>> }
>>> #endif
>>> +#if defined(__x86_64__)
>>> +// We cannot use glibc's clone wrapper, because it messes with the child
>>> +// task's TLS. It writes the PID and TID of the child task to its thread
>>> +// descriptor, but in our case the child task shares the thread
>>> descriptor with
>>> +// the parent (because we don't know how to allocate a new thread
>>> +// descriptor to keep glibc happy). So the stock version of clone(),
>>> when
>>> +// used with CLONE_VM, would end up corrupting the parent's thread
>>> descriptor.
>>> +uptr internal_clone(int (*fn)(void *), void *child_stack, int flags,
>>> void *arg,
>>> + int *parent_tidptr, void *newtls, int
>>> *child_tidptr) {
>>> + long long res;
>>> + if (!fn || !child_stack)
>>> + return -EINVAL;
>>> + CHECK_EQ(0, (uptr)child_stack % 16);
>>> + child_stack = (char *)child_stack - 2 * sizeof(void *);
>>> + ((void **)child_stack)[0] = (void *)(uptr)fn;
>>> + ((void **)child_stack)[1] = arg;
>>> + __asm__ __volatile__(
>>> + /* %rax = syscall(%rax = __NR_clone,
>>> + * %rdi = flags,
>>> + * %rsi = child_stack,
>>> + * %rdx = parent_tidptr,
>>> + * %r8 = new_tls,
>>> + * %r10 = child_tidptr)
>>> + */
>>> + "movq %6,%%r8\n"
>>> + "movq %7,%%r10\n"
>>> + ".cfi_endproc\n"
>>> + "syscall\n"
>>> +
>>> + /* if (%rax != 0)
>>> + * return;
>>> + */
>>> + "testq %%rax,%%rax\n"
>>> + "jnz 1f\n"
>>> +
>>> + /* In the child. Terminate unwind chain. */
>>> + ".cfi_startproc\n"
>>> + ".cfi_undefined %%rip;\n"
>>> + "xorq %%rbp,%%rbp\n"
>>> +
>>> + /* Call "fn(arg)". */
>>> + "popq %%rax\n"
>>> + "popq %%rdi\n"
>>> + "call *%%rax\n"
>>> +
>>> + /* Call _exit(%rax). */
>>> + "movq %%rax,%%rdi\n"
>>> + "movq %2,%%rax\n"
>>> + "syscall\n"
>>> +
>>> + /* Return to parent. */
>>> + "1:\n"
>>> + : "=a" (res)
>>> + : "a"(__NR_clone), "i"(__NR_exit),
>>> + "S"(child_stack),
>>> + "D"(flags),
>>> + "d"(parent_tidptr),
>>> + "r"(newtls),
>>> + "r"(child_tidptr)
>>> + : "rsp", "memory", "r8", "r10", "r11", "rcx");
>>> + return res;
>>> +}
>>> +#endif // defined(__x86_64__)
>>> } // namespace __sanitizer
>>> #endif // SANITIZER_LINUX
>>>
>>> Modified: compiler-rt/trunk/lib/**sanitizer_common/sanitizer_**linux.h
>>> URL: http://llvm.org/viewvc/llvm-**project/compiler-rt/trunk/lib/**
>>> sanitizer_common/sanitizer_**linux.h?rev=189753&r1=189752&**
>>> r2=189753&view=diff<http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.h?rev=189753&r1=189752&r2=189753&view=diff>
>>> ==============================**==============================**
>>> ==================
>>> --- compiler-rt/trunk/lib/**sanitizer_common/sanitizer_**linux.h
>>> (original)
>>> +++ compiler-rt/trunk/lib/**sanitizer_common/sanitizer_**linux.h Mon
>>> Sep 2 06:36:19 2013
>>> @@ -29,6 +29,10 @@ uptr internal_getdents(fd_t fd, struct l
>>> uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr
>>> arg5);
>>> uptr internal_sigaltstack(const struct sigaltstack* ss,
>>> struct sigaltstack* oss);
>>> +#ifdef __x86_64__
>>> +uptr internal_clone(int (*fn)(void *), void *child_stack, int flags,
>>> void *arg,
>>> + int *parent_tidptr, void *newtls, int
>>> *child_tidptr);
>>> +#endif
>>> // This class reads thread IDs from /proc/<pid>/task using only
>>> syscalls.
>>> class ThreadLister {
>>>
>>> Modified: compiler-rt/trunk/lib/**sanitizer_common/sanitizer_**
>>> stoptheworld_linux_libcdep.cc
>>> URL: http://llvm.org/viewvc/llvm-**project/compiler-rt/trunk/lib/**
>>> sanitizer_common/sanitizer_**stoptheworld_linux_libcdep.cc?**
>>> rev=189753&r1=189752&r2=**189753&view=diff<http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc?rev=189753&r1=189752&r2=189753&view=diff>
>>> ==============================**==============================**
>>> ==================
>>> --- compiler-rt/trunk/lib/**sanitizer_common/sanitizer_**stoptheworld_linux_libcdep.cc
>>> (original)
>>> +++ compiler-rt/trunk/lib/**sanitizer_common/sanitizer_**stoptheworld_linux_libcdep.cc
>>> Mon Sep 2 06:36:19 2013
>>> @@ -14,12 +14,12 @@
>>> #include "sanitizer_platform.h"
>>> -#if SANITIZER_LINUX
>>> +#if SANITIZER_LINUX && defined(__x86_64__)
>>> #include "sanitizer_stoptheworld.h"
>>> #include <errno.h>
>>> -#include <sched.h> // for clone
>>> +#include <sched.h> // for CLONE_* definitions
>>> #include <stddef.h>
>>> #include <sys/prctl.h> // for PR_* definitions
>>> #include <sys/ptrace.h> // for PTRACE_* definitions
>>> @@ -71,7 +71,6 @@
>>> // after it has exited. The following functions are used in this
>>> manner:
>>> // sigdelset()
>>> // sigprocmask()
>>> -// clone()
>>> COMPILER_CHECK(sizeof(**SuspendedThreadID) == sizeof(pid_t));
>>> @@ -371,11 +370,14 @@ void StopTheWorld(**StopTheWorldCallback c
>>> // Block the execution of TracerThread until after we have set ptrace
>>> // permissions.
>>> tracer_thread_argument.mutex.**Lock();
>>> - pid_t tracer_pid = clone(TracerThread, tracer_stack.Bottom(),
>>> - CLONE_VM | CLONE_FS | CLONE_FILES |
>>> CLONE_UNTRACED,
>>> - &tracer_thread_argument);
>>> - if (tracer_pid < 0) {
>>> - Report("Failed spawning a tracer thread (errno %d).\n", errno);
>>> + uptr tracer_pid = internal_clone(
>>> + TracerThread, tracer_stack.Bottom(),
>>> + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_UNTRACED,
>>> + &tracer_thread_argument, 0 /* parent_tidptr */, 0 /* newtls */, 0
>>> + /* child_tidptr */);
>>> + int local_errno = 0;
>>> + if (internal_iserror(tracer_pid, &local_errno)) {
>>> + Report("Failed spawning a tracer thread (errno %d).\n",
>>> local_errno);
>>> tracer_thread_argument.mutex.**Unlock();
>>> } else {
>>> // On some systems we have to explicitly declare that we want to
>>> be traced
>>> @@ -390,9 +392,8 @@ void StopTheWorld(**StopTheWorldCallback c
>>> // At this point, any signal will either be blocked or kill us, so
>>> waitpid
>>> // should never return (and set errno) while the tracer thread is
>>> alive.
>>> uptr waitpid_status = internal_waitpid(tracer_pid, NULL, __WALL);
>>> - int wperrno;
>>> - if (internal_iserror(waitpid_**status, &wperrno))
>>> - Report("Waiting on the tracer thread failed (errno %d).\n",
>>> wperrno);
>>> + if (internal_iserror(waitpid_**status, &local_errno))
>>> + Report("Waiting on the tracer thread failed (errno %d).\n",
>>> local_errno);
>>> }
>>> }
>>> @@ -448,4 +449,4 @@ uptr SuspendedThreadsList::**RegisterCount
>>> }
>>> } // namespace __sanitizer
>>> -#endif // SANITIZER_LINUX
>>> +#endif // SANITIZER_LINUX && defined(__x86_64__)
>>>
>>> Modified: compiler-rt/trunk/lib/**sanitizer_common/tests/**
>>> sanitizer_stoptheworld_test.cc
>>> URL: http://llvm.org/viewvc/llvm-**project/compiler-rt/trunk/lib/**
>>> sanitizer_common/tests/**sanitizer_stoptheworld_test.**
>>> cc?rev=189753&r1=189752&r2=**189753&view=diff<http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/tests/sanitizer_stoptheworld_test.cc?rev=189753&r1=189752&r2=189753&view=diff>
>>> ==============================**==============================**
>>> ==================
>>> --- compiler-rt/trunk/lib/**sanitizer_common/tests/**sanitizer_stoptheworld_test.cc
>>> (original)
>>> +++ compiler-rt/trunk/lib/**sanitizer_common/tests/**sanitizer_stoptheworld_test.cc
>>> Mon Sep 2 06:36:19 2013
>>> @@ -12,7 +12,7 @@
>>> //===-------------------------**------------------------------**
>>> ---------------===//
>>> #include "sanitizer_common/sanitizer_**platform.h"
>>> -#if SANITIZER_LINUX
>>> +#if SANITIZER_LINUX && defined(__x86_64__)
>>> #include "sanitizer_common/sanitizer_**stoptheworld.h"
>>> #include "gtest/gtest.h"
>>> @@ -191,4 +191,4 @@ TEST(StopTheWorld, SuspendThreadsAdvance
>>> } // namespace __sanitizer
>>> -#endif // SANITIZER_LINUX
>>> +#endif // SANITIZER_LINUX && defined(__x86_64__)
>>>
>>>
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>>> llvm-commits at cs.uiuc.edu
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>>>
>>>
>>
>>
>
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