[Bug sanitizer/100114] New: libasan built against latest glibc doesn't work

[Bug sanitizer/100114] New: libasan built against latest glibc doesn't work

[jakub at gcc dot gnu.org]

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.

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
As a quick hack, we could do something like:
#ifdef _SC_SIGSTKSZ
#define kAltStackSize (SIGSTKSZ * 4)
#else
static const uptr kAltStackSize = SIGSTKSZ * 4;  // SIGSTKSZ is not enough.
#endif
but the disadvantage is that sysconf will be called in that case on each use of
kAltStackSize.

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed by code inspection, but it's for sure sth not new (but would be nice
to fix before GCC 11.1).

I suggtest to simply move the initialization inside SetAlternateSignalStack.
Sth like

diff --git a/libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp
b/libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp
index d29438cf9db..803712e268e 100644
--- a/libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp
+++ b/libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp
@@ -165,7 +165,7 @@ bool SupportsColoredOutput(fd_t fd) {

 #if !SANITIZER_GO
 // TODO(glider): different tools may require different altstack size.
-static const uptr kAltStackSize = SIGSTKSZ * 4;  // SIGSTKSZ is not enough.
+static const uptr kAltStackSize;

 void SetAlternateSignalStack() {
   stack_t altstack, oldstack;
@@ -176,6 +176,7 @@ void SetAlternateSignalStack() {
   // 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()).
+  kAltStackSize = SIGSTKSZ * 4;  // SIGSTKSZ is not enough.
   void* base = MmapOrDie(kAltStackSize, __func__);
   altstack.ss_sp = (char*) base;
   altstack.ss_flags = 0;

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

--- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Richard Biener from comment #2)
> Confirmed by code inspection, but it's for sure sth not new (but would be
> nice to fix before GCC 11.1).
> 
> I suggtest to simply move the initialization inside SetAlternateSignalStack.
> Sth like
> 
> diff --git a/libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp
> b/libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp
> index d29438cf9db..803712e268e 100644
> --- a/libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp
> +++ b/libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp
> @@ -165,7 +165,7 @@ bool SupportsColoredOutput(fd_t fd) {
>  
>  #if !SANITIZER_GO
>  // TODO(glider): different tools may require different altstack size.
> -static const uptr kAltStackSize = SIGSTKSZ * 4;  // SIGSTKSZ is not enough.
> +static const uptr kAltStackSize;
>  
>  void SetAlternateSignalStack() {
>    stack_t altstack, oldstack;
> @@ -176,6 +176,7 @@ void SetAlternateSignalStack() {
>    // 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()).
> +  kAltStackSize = SIGSTKSZ * 4;  // SIGSTKSZ is not enough.
>    void* base = MmapOrDie(kAltStackSize, __func__);
>    altstack.ss_sp = (char*) base;
>    altstack.ss_flags = 0;

We can initialize it with a constructor or .init_array.

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
const vars in C++ can't be uninitialized nor modified.
And initializing those in constructor or .init_array is too late, the problem
is
that the function is called from .preinit_array handler, so before anything is
constructed.

I'd suggest
--- libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp.jj       
2020-11-13 19:00:46.909618582 +0100
+++ libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp   2021-04-16
15:19:56.211942944 +0200
@@ -165,7 +165,13 @@ bool SupportsColoredOutput(fd_t fd) {

 #if !SANITIZER_GO
 // TODO(glider): different tools may require different altstack size.
+#if SANITIZER_LINUX && defined(_SC_SIGSTKSZ)
+// In glibc 2.34 and later SIGSTKSZ is no longer a compile time constant,
+// but sysconf (_SC_SIGSTKSZ) call.
+static uptr kAltStackSize;
+#else
 static const uptr kAltStackSize = SIGSTKSZ * 4;  // SIGSTKSZ is not enough.
+#endif

 void SetAlternateSignalStack() {
   stack_t altstack, oldstack;
@@ -173,6 +179,9 @@ void SetAlternateSignalStack() {
   // 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;
+#if SANITIZER_LINUX && defined(_SC_SIGSTKSZ)
+  if (!kAltStackSize) kAltStackSize = SIGSTKSZ * 4;
+#endif
   // 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()).

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:d9f462fb372fb02da032cefd6b091d7582c425ae

commit r11-8230-gd9f462fb372fb02da032cefd6b091d7582c425ae
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Sat Apr 17 11:27:14 2021 +0200

    sanitizer: Fix asan against glibc 2.34 [PR100114]

    As mentioned in the PR, SIGSTKSZ is no longer a compile time constant in
    glibc 2.34 and later, so
    static const uptr kAltStackSize = SIGSTKSZ * 4;
    needs dynamic initialization, but is used by a function called indirectly
    from .preinit_array and therefore before the variable is constructed.
    This results in using 0 size instead and all asan instrumented programs
    die with:
    ==91==ERROR: AddressSanitizer failed to allocate 0x0 (0) bytes of
SetAlternateSignalStack (error code: 22)

    Here is a cherry-pick from upstream to fix this.

    2021-04-17  Jakub Jelinek  <jakub@redhat.com>

            PR sanitizer/100114
            * sanitizer_common/sanitizer_posix_libcdep.cpp: Cherry-pick
            llvm-project revisions 82150606fb11d28813ae6da1101f5bda638165fe
            and b93629dd335ffee2fc4b9b619bf86c3f9e6b0023.

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed on the trunk so far, guess some backporting will be useful.

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |11.0

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Yeah, backporting everywhere is needed.

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:950bac27d63c1c2ac3a6ed867692d6a13f21feb3

commit r10-9732-g950bac27d63c1c2ac3a6ed867692d6a13f21feb3
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Sat Apr 17 11:27:14 2021 +0200

    sanitizer: Fix asan against glibc 2.34 [PR100114]

    As mentioned in the PR, SIGSTKSZ is no longer a compile time constant in
    glibc 2.34 and later, so
    static const uptr kAltStackSize = SIGSTKSZ * 4;
    needs dynamic initialization, but is used by a function called indirectly
    from .preinit_array and therefore before the variable is constructed.
    This results in using 0 size instead and all asan instrumented programs
    die with:
    ==91==ERROR: AddressSanitizer failed to allocate 0x0 (0) bytes of
SetAlternateSignalStack (error code: 22)

    Here is a cherry-pick from upstream to fix this.

    2021-04-17  Jakub Jelinek  <jakub@redhat.com>

            PR sanitizer/100114
            * sanitizer_common/sanitizer_posix_libcdep.cpp: Cherry-pick
            llvm-project revisions 82150606fb11d28813ae6da1101f5bda638165fe
            and b93629dd335ffee2fc4b9b619bf86c3f9e6b0023.

    (cherry picked from commit d9f462fb372fb02da032cefd6b091d7582c425ae)

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:3d0135bf3be416bbe2531dc763d19b749eb2b856

commit r9-9450-g3d0135bf3be416bbe2531dc763d19b749eb2b856
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Sat Apr 17 11:27:14 2021 +0200

    sanitizer: Fix asan against glibc 2.34 [PR100114]

    As mentioned in the PR, SIGSTKSZ is no longer a compile time constant in
    glibc 2.34 and later, so
    static const uptr kAltStackSize = SIGSTKSZ * 4;
    needs dynamic initialization, but is used by a function called indirectly
    from .preinit_array and therefore before the variable is constructed.
    This results in using 0 size instead and all asan instrumented programs
    die with:
    ==91==ERROR: AddressSanitizer failed to allocate 0x0 (0) bytes of
SetAlternateSignalStack (error code: 22)

    Here is a cherry-pick from upstream to fix this.

    2021-04-17  Jakub Jelinek  <jakub@redhat.com>

            PR sanitizer/100114
            * sanitizer_common/sanitizer_posix_libcdep.cc: Cherry-pick
            llvm-project revisions 82150606fb11d28813ae6da1101f5bda638165fe
            and b93629dd335ffee2fc4b9b619bf86c3f9e6b0023.

    (cherry picked from commit 950bac27d63c1c2ac3a6ed867692d6a13f21feb3)

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-8 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:ef195a39d0d3b929cc676302d074b42c25460601

commit r8-10912-gef195a39d0d3b929cc676302d074b42c25460601
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Sat Apr 17 11:27:14 2021 +0200

    sanitizer: Fix asan against glibc 2.34 [PR100114]

    As mentioned in the PR, SIGSTKSZ is no longer a compile time constant in
    glibc 2.34 and later, so
    static const uptr kAltStackSize = SIGSTKSZ * 4;
    needs dynamic initialization, but is used by a function called indirectly
    from .preinit_array and therefore before the variable is constructed.
    This results in using 0 size instead and all asan instrumented programs
    die with:
    ==91==ERROR: AddressSanitizer failed to allocate 0x0 (0) bytes of
SetAlternateSignalStack (error code: 22)

    Here is a cherry-pick from upstream to fix this.

    2021-04-17  Jakub Jelinek  <jakub@redhat.com>

            PR sanitizer/100114
            * sanitizer_common/sanitizer_posix_libcdep.cc: Cherry-pick
            llvm-project revisions 82150606fb11d28813ae6da1101f5bda638165fe
            and b93629dd335ffee2fc4b9b619bf86c3f9e6b0023.

    (cherry picked from commit 950bac27d63c1c2ac3a6ed867692d6a13f21feb3)

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED
           Assignee|unassigned at gcc dot gnu.org      |jakub at gcc dot gnu.org

--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114
Bug 100114 depends on bug 101749, which changed state.

Bug 101749 Summary: gcc -static-libasan broken because libasan.a needs __cxa_guard_release in libstdc++
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101749

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |8.5

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[alexander.enaldiev at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

Alexander Enaldiev <alexander.enaldiev at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |alexander.enaldiev at gmail dot co
                   |                            |m

--- Comment #12 from Alexander Enaldiev <alexander.enaldiev at gmail dot com> ---
I just've seen it by compiling carbon-lang:
https://github.com/carbon-language/carbon-lang

(it could be reproduced when one downloads LLVM15 via homebrew as listed at
carbon-lang README.md -- LLVM14 doesn't reproduce)

More: https://github.com/carbon-language/carbon-lang/issues/2236

But here I see status 'RESOLVED FIXED'. Do you presume, my today's issue isn't
connected?

[Bug sanitizer/100114] libasan built against latest glibc doesn't work

[fw at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100114

--- Comment #13 from Florian Weimer <fw at gcc dot gnu.org> ---
(In reply to Alexander Enaldiev from comment #12)
> But here I see status 'RESOLVED FIXED'. Do you presume, my today's issue
> isn't connected?

It could still be the same bug. It's supposed to be fixed in LLVM 13 and later,
but maybe your program links against system libasan.a, which may not have been
fixed yet by your distribution.