<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=http://email.email.llvm.org/c/eJy1Vtty2zYQ_RrqBSMOCIq3Bz3Ykt1oxnU9zbjJGwcEQBEpRHAA0LL69V2QuidO47TlcCgKWJ7ds4u9VJrv5h9kQBYBXgb45lMjWlT1UnHZrtFmh2jXKcmok7pFdE1lax1SsurbrWz5NIpRQHLqENObjXSomKU5xXWRxHmSs7RIa5bQWTKbESzqGStSESdpnDG0la7x8E5rxRqAHZS6cR1Nlw-r28Xnzze3q_L541358PDHr-Xz46fV4_Lu9yBe_vYYkAI0LxDoZIbaRlgEVlhHjes7tPUsGFXKk7B6I1DnGiMoR66BpXDkOj4_CCMCkllke9YgOsJ5VgDdAHvRWiRaJ41QOwR2BoS02k03uynTHL4koxkDBEV7NYr2LWsER9UOdbITW_gc9gS4ru1fEe251OjmaQU0gvjm3Jwgxft7_EvyNa8828odVmKMEH7FcCUJrXFSY15jPNgW38PtjffAB_HoIJ7VcGV5lfOEe3EIYrkWruyMZqVsa73_EtVGb1AYBuQeQj0-x4CHVofREZhcA3OREg9cPg_S5S_CPdB23dO1-NgJJmvJltTRd6qJL9TMGK8EH-wvyzVjZSeM1S1V0u3KF-yxX2AFzisclCBe6M7JjfwLYqF7F8R3PlyU-fNs3xYQr0x0XqZkitrvCPaibCDgwoAIfvUGUp7VlFXY744UEFxMt068ugupAnPs3QAHF8gPSQe_QAme1rDjO7hlfNknHQsZHJoomR09NLv2UIGr2Xkg7rVhgu__PDXUCuIdBTS_affb1i4gaHQjbNldbOY1Px05z_ednELZDpxycuSUfMUpq8hbnL5HxjrdvR1Av1tSs-43kOSXhFmG_wNOJMqOnNLLhMkiGmdjnMp9gSr7I59jhnhEa86zZC_s0-RYJ-LsChzXDBce3Mo1oy0Tqmxoy5UwP4OeI6guC4CCTEMHHF9iBfeePIgVl1Gr6rwgwhshOq1UuaXS_YN25vWmp-KFzwHjpIKwFl_Vum-C2Y5OcUj8W9912rhxxy_vF0DVSVF0pSgq8vR_UUTOFfnyXWTZjynywdl3E1AYX0YIevHl4YpIMsbfd8Vy35l-IvTR7DqmiYg9MFO6Fe8J51VvG54raPra_GlRLQHsB_v__T3SBvllFJGh9Z56xzn4k6Ku1mYDeXiaamCSYZDsGsr6TQ5ev0U1lcr6ddru9i2aS-uMRiuohb2CucHswgmfx7yICzqhvWu0mX-BnBJGCjPpjZo3znUeEnj7kgBE-iqEucj7Qb0cfqbQbL8I5o-ItLYXFl4SAnPTpAH0JInqiMKQRCrKcYFj2MlEEdM6rTCZKFoJZedBcuunELFFA4SfQZLl5N9bIOcEE4IjHEUwscVxOKNRnUZE0CzLI7iDGRYb8FXocUJt1hMzHyCrfm1hU4HT7GkTOifUCyEGg8FCJ50S82OkEJzYYdqaDHbMByP-BqVFOpU>52946</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            libunwind 13 crash
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          jcelerier
      </td>
    </tr>
</table>

<pre>
    Hi,
When building my application against libunwind-13 (at commit 9468a0f953858c696fc5a454420ef4c96e35637c with my toolchain built with  -DLIBCXXABI_USE_LLVM_UNWINDER=ON) , it crashes at startup when calling some pthread thing.

Here's such a crash (it happens entirely in "not-my-code", it's a thread launched by pipewire the linux audio API):

```
(gdb) bt
#0  0x000055af05f0df00 in ?? ()
#1  0x00007ffff78b8d5d in unw_get_proc_info () from ../lib/libunwind.so.1
#2  0x00007ffff78bde62 in _Unwind_GetLanguageSpecificData () from ../lib/libunwind.so.1
#3  0x00007ffff4cdbedd in __gcc_personality_v0 (version=<optimized out>, actions=<optimized out>, exception_class=<optimized out>, ue_header=0x7fffad7facb0, 
    context=0x7fffad7f90d0) at /build/gcc/src/gcc/libgcc/unwind-c.c:154
#4  0x00007ffff4cd90b4 in _Unwind_ForcedUnwind_Phase2 (exc=0x7fffad7facb0, context=0x7fffad7f90d0, frames_p=0x7fffad7f8fd8)
    at /build/gcc/src/gcc/libgcc/unwind.inc:182
#5  0x00007ffff4cd97b2 in _Unwind_ForcedUnwind (exc=0x7fffad7facb0, stop=<optimized out>, stop_argument=0x7fffad7f9c70)
    at /build/gcc/src/gcc/libgcc/unwind.inc:217
#6  0x00007ffff771a374 in __pthread_unwind () from /usr/lib/libpthread.so.0
#7  0x00007ffff770fc09 in sigcancel_handler () from /usr/lib/libpthread.so.0
#8  <signal handler called>
#9  0x00007ffff4bf892e in epoll_wait () from /usr/lib/libc.so.6
#10 0x00007ffff35bacb9 in ?? () from /usr/lib/spa-0.2/support/libspa-support.so
#11 0x00007ffff35b1986 in ?? () from /usr/lib/spa-0.2/support/libspa-support.so
#12 0x00007ffff05f0977 in ?? () from /usr/lib/libpipewire-0.3.so.0
#13 0x00007ffff7711259 in start_thread () from /usr/lib/libpthread.so.0
#14 0x00007ffff4bf85e3 in clone () from /usr/lib/libc.so.6
```

It works fine with  -DLIBCXXABI_USE_LLVM_UNWINDER=OFF or LLVM 12's libunwind.

Platform: building on centos:8 ; fails on any linux distro I could try.
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJy1VltzmzgU_jX4RWNGCDDw4IfETraeyWYz20nbN0ZIwqgrI0YScby_fo_A9zbdprPLMBhLh--c71xVab6bf5ABWQR4GeCbz41oUdVLxWW7Rpsdol2nJKNO6hbRNZWtdUjJqm-3suXTKEYByalDTG820qEimeUU10Ua52nOZsWsZilN0iQhWNQJK2YiTmdxxtBWusbDO60VawB2UOrGdTRdPqxuF1--3NyuyuePd-XDw6ffy-fHz6vH5d2fQbz84zEgBWheINDJDLWNsAissI4a13do61kwqpQnYfVGoM41RlCOXANL4ch1fH4QRgQks8j2rEF0hPOsALoB9qK1SLROGqF2COwMCGm1m252U6Y5fElGMwYIivZqFO1b1giOqh3qZCe28DnsCXBd278i2nOp0c3TCmgE8c25OcEM7-_xL8nXvPJsK3dYiTFC-BXDlaa0xmmNeY3xYFt8D7c33gMfxKODeFbDleVVzlPuxSGI5Vq4sjOalbKt9f5LVBu9QWEYkHsI9fgcAx5aHUZHYHINzMWMeODyeZAufxPugbbrnq7Fx04wWUu2pI6-U018oSZhvBJ8sL8s14yVnTBWt1RJtytfsMd-gRXIV0iUIF7ozsmN_BtioXsXxHc-XJT5fLZvC4hXJjovUzJF7Q8Ee1E2EHBhQAS_egMpz2rKKux3RwoILqZbJ17dhVSBOfZugMQF8kPRwS9Qgqc17PgObhlf9kXHQgZJE6XJ0UPJtYcKXCXngbjXhgm-__PUUCuIdxTQ_K7db1u7gKDRjbBld7GZ1_yUcp7vOzmFsh045eTIKf2GU1aRtzj9iIx1uns7gH63pGbdb6DILwmzDP8HnEiUHTnNLgsmi2icjXEq9w2q7I98jhXiEa05r5K9sC-TY5-IsytwXDNceHAr14y2TKiyoS1XwvwKeo6guywACioNHXB8ixXce_IgVlxGrarzgghvhOi0UuWWSvcv2pnXOzs1L3wOGKcVhLX4ptd9F8x2dIpD4t_6rtPGjTt-eb8Aqk6KoitFUZHP_hdF5FyRb99Flv2cIh-c_TQBhfFlhGAWXyZXRNIx_n4qlvvJ9Auhj5LrmKYi9sBM6Va8J5xXs214rmDoa_OXRbUEsJ-c__f3SBvkl1FEhtF7mh3n4E-KulqbDdTh6VQDJxkGxa6hrd_k4PVbVFOprF-n7W4_orm0zmi0gl7YKzg3mF044fOYF3FBJ046JeZHlQhcPxwbJr1R88a5zkMDf98agFBfhXA-8v5QL4efKQzdr4L5VJHW9sLCS0rg_DRp5lVVUFqLGcsKlldVAhnCM8ZxFseM1Vk1UbQSys6D9NafRsQWDRD-LJIuJ3JOMCE4wlEE5644DhMa1bOICJpleQR3kGCxAcahtyPUZj0x88Gkql9b2FRA3Z42Yf5B1QsxqAN82rtGm_lXaCjCSGEmg_L5YPw_w2UmgQ">