Fix ASan CHECK failure when exceptions are thrown during early
initialization, particularly in Python bindings that load Ceph
shared libraries.

ASan reported the following error:

  AddressSanitizer: CHECK failed: asan_interceptors.cpp:335
  "((__interception::real___cxa_throw)) != (0)" (0x0, 0x0)
    #0 CheckUnwind asan_rtl.cpp:69
    #1 CheckFailed sanitizer_termination.cpp:86
    #2 __interceptor___cxa_throw asan_interceptors.cpp:335
    #3 boost::throw_exception<boost::bad_lexical_cast>
    #4 boost::conversion::detail::throw_bad_cast
    #5 boost::lexical_cast<unsigned long, std::string>
    #6 librbd::rbd_features_from_string /ceph/src/librbd/Features.cc:67
    #7 get_rbd_options()::$_2::operator() rbd_options.cc:44
    #8 Option::pre_validate /ceph/src/common/options.cc:94
    #9 md_config_t::md_config_t /ceph/src/common/config.cc:208
    #10 CephContext::CephContext /ceph/src/common/ceph_context.cc:730
    #11 rados_create_cct /ceph/src/librados/librados_c.cc:120
    #12 Python rados module initialization

Root cause: When Python loads the Ceph shared library (e.g., rados.so),
CephContext initialization validates configuration options. The RBD
default features option validator calls rbd_features_from_string(),
which uses boost::lexical_cast to parse the feature string. When the
string is not numeric (e.g., "layering,exclusive-lock,..."), lexical_cast
throws boost::bad_lexical_cast.

This exception is properly caught and handled in the code. However, ASan's
exception interceptor (__cxa_throw) may not be fully initialized when
exceptions are thrown during early library initialization, causing a CHECK
failure.

Why qa/asan.supp is not sufficient:
The existing suppression in qa/asan.supp for __interceptor___cxa_throw
only suppresses ASan *reports* about the interceptor. It does NOT prevent
CHECK failures in ASan's runtime itself. CHECK failures are assertions
that terminate the program immediately, before any suppression mechanism
can be applied. The CHECK fails because real___cxa_throw is NULL (not yet
initialized), which is a precondition violation in ASan's interceptor code.

Suppressions work by filtering ASan's output after an issue is detected,
but they cannot prevent internal CHECK failures in ASan's initialization
logic.

Solution: Disable ASan's C++ exception interception by adding
intercept_cxx_exceptions=0 to ASAN_OPTIONS. This prevents ASan from
intercepting exception throws/catches, avoiding the initialization order
issue. Exception handling still works correctly; we just lose ASan's
ability to detect exception-related memory issues.

This is a known limitation when using ASan with code that throws
exceptions during static/early initialization, particularly in shared
libraries loaded by interpreters like Python.

Note: This does not hide real bugs - the exception is properly caught
and handled. We're only disabling ASan's interception mechanism to avoid
the initialization order problem.

Signed-off-by: Kefu Chai <k.chai@proxmox.com>

The ConcurrentOperations test had a race condition where threads
create_snap2 and create_snap3 were started before image1 finished
its snap_create and aio_close operations.

Since image1 holds the exclusive lock, when create_snap2 and
create_snap3 try to create snapshots, they must either:
1. Send remote requests to image1 (the lock owner), or
2. Wait to acquire the lock after image1 releases it

However, image1 is busy completing its own snap_create and then
executing aio_close, so it cannot process remote requests properly.
This causes the remote requests to timeout or fail, resulting in
snap_create returning non-zero error codes and triggering the
ceph_assert(r == 0) failures.

The fix ensures image1 fully completes (including aio_close and lock
release) before starting create_snap2 and create_snap3 threads. This
allows image2 or image3 to acquire the lock cleanly instead of trying
to coordinate with a closing image.

Fixes: https://tracker.ceph.com/issues/70691
Signed-off-by: Kefu Chai <k.chai@proxmox.com>

Environment variables set via CMake's set_property(TEST ... PROPERTY ENVIRONMENT)
are available in the test shell process but are not automatically exported to child
processes. This causes sanitizer options like ASAN_OPTIONS to not propagate to
spawned ceph daemons and CLI tools.

The safe-to-destroy.sh test and other standalone tests spawn multiple child
processes (ceph, ceph-osd, ceph-mon, Python bindings). When these load shared
libraries during initialization, ASan's exception interceptor fails because
ASAN_OPTIONS=intercept_cxx_exceptions=0 (set in f0e2646) is not inherited.

Fix by explicitly exporting ASAN_OPTIONS, LSAN_OPTIONS, UBSAN_OPTIONS, and
TSAN_OPTIONS. Since detect-build-env-vars.sh is sourced by all standalone test
scripts, this ensures sanitizer options propagate to all child processes uniformly.

Signed-off-by: Kefu Chai <k.chai@proxmox.com>

When running readable.sh with a WITH_ASAN=ON build of ceph-dencoder,
ASAN processes need to find a contiguous 16+ TB shadow memory region
(1/8 of the 128 TB x86-64 user VA space). High ASLR entropy can
fragment the VA space, preventing ASAN from finding a suitable region.

Instead of requiring system-wide vm.mmap_rnd_bits=28 (which weakens
ASLR security for the entire host), wrap ceph-dencoder with 'setarch
$(uname -m) -R' when ASAN is detected. This disables ASLR only for the
specific ceph-dencoder processes, with no system-wide security impact.

Also simplify parallelism logic: extract NPROC calculation into a shared
variable and use it consistently across FreeBSD, Darwin, and Linux.

Reference: https://clang.llvm.org/docs/AddressSanitizer.html

Signed-off-by: Kefu Chai <k.chai@proxmox.com>

When co_waiter is destroyed, the cancellation slot may still hold a
reference to the op_cancellation callback which captures 'this'. If
the cancellation signal is emitted after co_waiter is destroyed (e.g.,
during co_throttle shutdown), it results in a stack-use-after-scope
error.

Fix by adding a destructor that retrieves the cancellation slot from
the handler (if still active) and clears it before destruction. This
ensures the cancellation callback is removed before the co_waiter
object goes out of scope, preventing use-after-scope errors.

The cancellation slot cannot be stored as a member variable because
it becomes invalid after the handler is moved out in complete(). Instead,
we retrieve it on demand from the handler in the destructor, which is
the only place we need it.

Signed-off-by: Kefu Chai <k.chai@proxmox.com>

rbd_features_from_string() uses boost::lexical_cast which throws
bad_lexical_cast when the input is not numeric. The exception is caught
and handled as "parse as feature name list instead".

This is normal control flow, but when ASAN's __cxa_throw interceptor is
misconfigured (e.g. with intercept_cxx_exceptions=0 leaving real___cxa_throw
NULL), any exception causes a CHECK failure. Even with a correctly configured
ASAN, throwing exceptions during config initialization adds overhead.

Replace the try/catch pattern with boost::conversion::try_lexical_convert,
which returns false on parse failure instead of throwing. This eliminates
the exception entirely, making the code more efficient and avoiding any
interaction with ASAN's exception interceptor.

The ASan report:

```
AddressSanitizer: CHECK failed: asan_interceptors.cpp:320 "((__interception::real___cxa_throw)) != (0)" (0x0, 0x0) (tid=30529)
    #0 0x7d668fac9a09 in CheckUnwind ../../../../src/libsanitizer/asan/asan_rtl.cpp:67
    #1 0x7d668faec105 in __sanitizer::CheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) ../../../../src/libsanitizer/sanitizer_common/sanitizer_termination.cpp:86
    #2 0x7d668fa4b194 in __interceptor___cxa_throw ../../../../src/libsanitizer/asan/asan_interceptors.cpp:320
    #3 0x7d668ae4ec0f in void boost::throw_exception<boost::bad_lexical_cast>(boost::bad_lexical_cast const&) /opt/ceph/include/boost/throw_exception.hpp:165
    #4 0x7d668c1e1e0b in void boost::conversion::detail::throw_bad_cast<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, unsigned long>() /opt/ceph/include/boost/lexical_cast/bad_lexical_cast.hpp:93
    #5 0x7d668c1e0e05 in unsigned long boost::lexical_cast<unsigned long, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) /opt/ceph/include/boost/lexical_cast.hpp:43
    #6 0x7d668c1df609 in librbd::rbd_features_from_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::ostream*) /ceph/src/librbd/Features.cc:67
    #7 0x7d668b255a35 in get_rbd_options()::$_2::operator()(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*) const src/common/options/rbd_options.cc:44
    #8 0x7d668b255806 in int std::__invoke_impl<int, get_rbd_options()::$_2&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*>(std::__invoke_other, get_rbd_options()::$_2&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*&&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*&&) /usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/invoke.h:61
    #9 0x7d668b255754 in std::enable_if<is_invocable_r_v<int, get_rbd_options()::$_2&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*>, int>::type std::__invoke_r<int, get_rbd_options()::$_2&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*>(get_rbd_options()::$_2&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*&&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*&&) /usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/invoke.h:114
    #10 0x7d668b25563c in std::_Function_handler<int (std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*), get_rbd_options()::$_2>::_M_invoke(std::_Any_data const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*&&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*&&) /usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/std_function.h:290
    #11 0x7d668af924f1 in std::function<int (std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*)>::operator()(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*) const /usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/std_function.h:591
    #12 0x7d668af8c495 in Option::pre_validate(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*) const /ceph/src/common/options.cc:94
    ceph#13 0x7d668aef9ec3 in md_config_t::md_config_t(ConfigValues&, ConfigTracker const&, bool) /ceph/src/common/config.cc:208
    ceph#14 0x7d668ae0040d in ceph::common::ConfigProxy::ConfigProxy(bool) /ceph/src/common/config_proxy.h:70
    ceph#15 0x7d668adf3f5d in ceph::common::CephContext::CephContext(unsigned int, ceph::common::CephContext::create_options const&) /ceph/src/common/ceph_context.cc:730
    ceph#16 0x7d668adf3785 in ceph::common::CephContext::CephContext(unsigned int, code_environment_t, int) /ceph/src/common/ceph_context.cc:724
    ceph#17 0x7d668aef5ee6 in common_preinit(CephInitParameters const&, code_environment_t, int) /ceph/src/common/common_init.cc:40
    ceph#18 0x7d668d4a47af in rados_create_cct(char const*, CephInitParameters*) /ceph/src/librados/librados_c.cc:120
    ceph#19 0x7d668d4a49db in _rados_create2 /ceph/src/librados/librados_c.cc:168
    ceph#20 0x7d668d94dc4b in __pyx_pf_5rados_5Rados_2__setup /ceph/build/src/pybind/rados/rados_processed.c:13219
    ceph#21 0x7d668d94dc4b in __pyx_pw_5rados_5Rados_3__setup /ceph/build/src/pybind/rados/rados_processed.c:12703
    ceph#22 0x7d668d94a347 in __Pyx_CyFunction_CallAsMethod /ceph/build/src/pybind/rados/rados_processed.c:93157
    ceph#23 0x58ac5086d0ba in _PyObject_MakeTpCall (/usr/bin/python3.10+0x1810ba)
    ceph#24 0x58ac508843da  (/usr/bin/python3.10+0x1983da)
    ceph#25 0x58ac50885076 in PyVectorcall_Call (/usr/bin/python3.10+0x199076)
    ceph#26 0x7d668d94cdd7 in __Pyx_PyObject_Call /ceph/build/src/pybind/rados/rados_processed.c:90994
    ceph#27 0x7d668d94cdd7 in __pyx_pf_5rados_5Rados___init__ /ceph/build/src/pybind/rados/rados_processed.c:12474
    ceph#28 0x7d668d94cdd7 in __pyx_pw_5rados_5Rados_1__init__ /ceph/build/src/pybind/rados/rados_processed.c:12443
    ceph#29 0x58ac5086d43a  (/usr/bin/python3.10+0x18143a)
    ceph#30 0x58ac50884d3a in PyObject_Call (/usr/bin/python3.10+0x198d3a)
    ceph#31 0x58ac508637de in _PyEval_EvalFrameDefault (/usr/bin/python3.10+0x1777de)
    ceph#32 0x58ac5087702b in _PyFunction_Vectorcall (/usr/bin/python3.10+0x18b02b)
    ceph#33 0x58ac508615fe in _PyEval_EvalFrameDefault (/usr/bin/python3.10+0x1755fe)
    ceph#34 0x58ac5087702b in _PyFunction_Vectorcall (/usr/bin/python3.10+0x18b02b)
    ceph#35 0x58ac508615fe in _PyEval_EvalFrameDefault (/usr/bin/python3.10+0x1755fe)
```

Signed-off-by: Kefu Chai <k.chai@proxmox.com>