<div dir="ltr">Hello,<br><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Sep 8, 2015 at 10:33 AM, Ahmed Omar <span dir="ltr"><<a href="mailto:spawn.think@gmail.com" target="_blank">spawn.think@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr">Hi, <div>We have been experiencing a segfault on our servers running a custom version of Ejabberd. We managed to get a core file from the last crash</div><div>This is what we see running gdb on it:</div><div>######</div><div><div>Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols found)...done.</div><div>Loaded symbols for /lib64/ld-linux-x86-64.so.2</div><div>Core was generated by `/var/lib/ejabberd/erts-5.10.4/bin/beam.smp -K true -A 128 -P 2500000 -Q 500000'.</div><div>Program terminated with signal 11, Segmentation fault.</div><div>#0 0x000000000044d299 in link_free_block (allctr=0x15e32c0, block=0x128) at beam/erl_goodfit_alloc.c:439</div><div>439<span style="white-space:pre-wrap"> </span>beam/erl_goodfit_alloc.c: No such file or directory.</div><div><span style="white-space:pre-wrap"> </span>in beam/erl_goodfit_alloc.c</div></div><div>######</div><div><br></div><div>If we run bt full in gdb we get:</div><div>######</div><div><div><div>(gdb) bt full</div><div>#0 0x000000000044d299 in link_free_block (allctr=0x15e32c0, block=0x128) at beam/erl_goodfit_alloc.c:439</div><div> gfallctr = 0x15e32c0</div><div> blk = 0x128</div><div> sz = 0</div><div> i = <value optimized out></div><div>#1 0x00000000015e32c0 in ?? ()</div><div>No symbol table info available.</div><div>#2 0x0000000000442fa6 in mbc_realloc (allctr=0x7fe0848807a8, p=0x11f, size=Unhandled dwarf expression opcode 0xf3</div><div>) at beam/erl_alloc_util.c:2370</div><div> crr = 0x128</div><div> new_p = <value optimized out></div><div> old_blk_sz = 287</div><div> blk = 0x117</div><div> new_blk = <value optimized out></div><div> cand_blk = <value optimized out></div><div> cand_blk_sz = <value optimized out></div><div> blk_sz = 3748409</div><div> nxt_blk = 0x236</div><div> nxt_blk_sz = 22950592</div><div> is_last_blk = 296</div><div> get_blk_sz = 140602277246336</div><div>#3 0x0000000000000000 in ?? ()</div><div>No symbol table info available.</div></div><div>#######</div><div><br></div><div>Is there a way to get more information? maybe which driver made the realloc call?</div></div></div></blockquote><div><br></div><div>Something is wrong/missing from this stacktrace. The gdb that you are using does not seem to understand the dwarf2 extension (at least that's what I guess after googling "Unhandled dwarf expression opcode 0xf3"), and can only find two of the frames. Try to install a later version of gdb and then do a bt full.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div><div><br></div><div><div><div dir="ltr">Best Regards,<br>- Ahmed Omar<div><span style="color:rgb(51,51,51);font-family:proxima-nova-1,proxima-nova-2,Tahoma,Helvetica,Verdana,sans-serif;font-size:14px;line-height:18px"><a href="http://about.me/spawn.think/" target="_blank">http://about.me/spawn.think/</a></span></div></div></div></div>
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