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Date:      Thu, 15 Feb 2018 11:00:30 +0100
From:      Per olof Ljungmark <peo@nethead.se>
To:        Michael Schuster <michaelsprivate@gmail.com>
Cc:        FreeBSD Mailing List <freebsd-questions@freebsd.org>, ume@FreeBSD.org
Subject:   Re: which limit is hit here?
Message-ID:  <fcaa9470-adeb-9dc8-7338-7efd7ee781e3@nethead.se>
In-Reply-To: <CADqw_gKJH5OPeXCin_344=yVRBeYXGP62NAZuTi9MMt6LDQzgA@mail.gmail.com>
References:  <d4d1093d-0db2-baed-0fb5-04b5127c8ccb@nethead.se> <CADqw_gKS=%2Be=PCgG6OJVfbuSwWD4zioZ__gnVNc5hYtM2Mfo%2Bg@mail.gmail.com> <71635f3b-0494-1956-fa31-bd8df7b72a93@nethead.se> <CADqw_g%2BQ0=jbqD9wnYnprXtrUvcz5Lg8AHGMmNrHO8K-UthOgQ@mail.gmail.com> <e29cfb8e-c199-4b5c-7580-71646c807a52@nethead.se> <CADqw_gKOr9va7-ffzVJYm4=kL=8m1PLGkqhY7AOQdpdgDNo_Tw@mail.gmail.com> <0d45799f-cd71-86e2-9c70-d8da3b64364d@nethead.se> <CADqw_gKJH5OPeXCin_344=yVRBeYXGP62NAZuTi9MMt6LDQzgA@mail.gmail.com>

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On 02/15/18 10:56, Michael Schuster wrote:
> 
> 
> On Thu, Feb 15, 2018 at 10:54 AM, Per olof Ljungmark <peo@nethead.se
> <mailto:peo@nethead.se>> wrote:
> 
>     On 02/15/18 10:31, Michael Schuster wrote:
>     >
>     >
>     > On Thu, Feb 15, 2018 at 10:27 AM, Per olof Ljungmark <peo@nethead.se <mailto:peo@nethead.se>
>     > <mailto:peo@nethead.se <mailto:peo@nethead.se>>> wrote:
>     >
>     >
>     >
>     >     On 02/15/18 10:07, Michael Schuster wrote:
>     >     > hmm ... 
>     >     >
>     >     > what does gdb's "info shared" print out?
>     >
>     >     "No shared libraries loaded at this time."
>     >
>     >
>     > is that really all?
> 
>     Yes, that is what is says.
> 
> 
> in that case, someone with more intimate knowledge of (and access to)
> FreeBSD and/or Cyrus-IMAP will have to step in ... sorry :-)

Like the maintainer of the port ...?

Thank you anyway!

>     >  I'd expect something like this (library names removed by me) - this is
>     > not on BSD, btw, but I'd expect gdb to behave in a similar fashion:
>     >
>     > (gdb) info shared
>     > From        To          Syms Read   Shared Object Library
>     > 0x01120000  0x011b090c  Yes         xxxx
>     > 0x78a3e000  0x78a64660  Yes (*)     xxxxxx
>     > 0x78317000  0x7831d290  Yes (*)     xxxxxx.so
>     > 0x78087000  0x78087000  No          xxxxxxxxxxxx.so.1.1
>     > 0x78056000  0x78056000  No          xxxxxxxxxx.1.2
>     > 0x7801f000  0x7801f000  No          xxxxxxxxxxxxso.1.0
>     > 0x7800c000  0x7800c000  No          xxxxxxxxxx.so.1.0
>     > 0x78000000  0x78000000  No          xxxxxxxxxxxxxx.so.1.0
>     > 0x78017000  0x78017000  No          xxxxxxxxx.so.1.0
>     > 0x78129000  0x7819f960  Yes         xxxxxxso
>     > 0x78037000  0x78040768  Yes         xxxxxxxx.so
>     > 0x78025000  0x7802f6e0  Yes         xxxxxxxxso.2
>     > 0x78047000  0x78054970  Yes         xxxxxxxxxxx.so
>     > (*): Shared library is missing debugging information.
>     > (gdb)
>     >
>     >  
>     >
>     >
>     >     >
>     >     > On Thu, Feb 15, 2018 at 10:06 AM, Per olof Ljungmark <peo@nethead.se <mailto:peo@nethead.se> <mailto:peo@nethead.se
>     <mailto:peo@nethead.se>>
>     >     > <mailto:peo@nethead.se <mailto:peo@nethead.se>
>     <mailto:peo@nethead.se <mailto:peo@nethead.se>>>> wrote:
>     >     >
>     >     >     On 02/15/18 08:56, Michael Schuster wrote:
>     >     >     > Hi Per,
>     >     >     >
>     >     >     > On Thu, Feb 15, 2018 at 8:41 AM, Per olof Ljungmark
>     <peo@nethead.se <mailto:peo@nethead.se> <mailto:peo@nethead.se
>     <mailto:peo@nethead.se>> <mailto:peo@nethead.se <mailto:peo@nethead.se>
>     >     <mailto:peo@nethead.se <mailto:peo@nethead.se>>>
>     >     >     > <mailto:peo@nethead.se <mailto:peo@nethead.se>
>     <mailto:peo@nethead.se <mailto:peo@nethead.se>>
>     >     <mailto:peo@nethead.se <mailto:peo@nethead.se>
>     <mailto:peo@nethead.se <mailto:peo@nethead.se>>>>> wrote:
>     >     >     >
>     >     >     >     Hi,
>     >     >     >
>     >     >     >     A process "squatter" from Cyrus-IMAP version 2.5.11
>     >     exits with signal
>     >     >     >     11. The purpose of the process is to create an
>     index of
>     >     the content in a
>     >     >     >     mailbox.
>     >     >     >
>     >     >     >     On large mailboxes, squatter coredumps, the final
>     >     message from truss
>     >     >     >     reads:
>     >     >     >
>     >     >     >   
>     >   
>       mmap(0x0,700448768,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANON,-1,0x0) =
>     >     >     >     34783363072 (0x819400000)
>     >     >     >     mmap(0x0,936334732,PROT_READ,MAP_SHARED,107,0x0) =
>     >     35483811840
>     >     >     >     (0x843000000)
>     >     >     >     SIGNAL 11 (SIGSEGV)
>     >     >     >     process killed, signal = 11 (core dumped)
>     >     >     >
>     >     >     >
>     >     >     > to me this looks like the error is happening *after*
>     mmap()
>     >     returned
>     >     >     > successfully - most likely because "someone" miscalculates
>     >     some pointer
>     >     >     > and tries to access an unmapped address. Maybe (but that's
>     >     conjecture),
>     >     >     > PROT_READ is wrong here and someone is attempting to write
>     >     to that
>     >     >     > mapped region; I'm not 100% sure though whether that'd
>     >     actually trigger
>     >     >     > SIGSEGV.
>     >     >     >
>     >     >     > I'd suggest you do something like
>     >     >     > $ gdb squatter core
>     >     >     > (gdb) bt
>     >     >     >
>     >     >     > and look at the output, and maybe go to the maintainers of
>     >     Cyrus-IMAP...
>     >     >
>     >     >     Hi,
>     >     >
>     >     >     gdb says,
>     >     >
>     >     >     (gdb) bt
>     >     >     #0  0x00000000004049cc in ?? ()
>     >     >     #1  0x0000000803456da4 in ?? ()
>     >     >     #2  0x0000000804445130 in ?? ()
>     >     >     #3  0x003875e5ffffcb00 in ?? ()
>     >     >     #4  0x00000008047e7008 in ?? ()
>     >     >     #5  0x00000008047e7048 in ?? ()
>     >     >     #6  0x00000001040000c0 in ?? ()
>     >     >     #7  0x0000000810800000 in ?? ()
>     >     >     #8  0x0000000200000045 in ?? ()
>     >     >     #9  0x000000083a400000 in ?? ()
>     >     >     #10 0x00000008047e8e98 in ?? ()
>     >     >     #11 0x00000000000003bb in ?? ()
>     >     >     #12 0x00000008047e8eb8 in ?? ()
>     >     >     #13 0x00000000000000bf in ?? ()
>     >     >     #14 0x0ffd2a151071e550 in ?? ()
>     >     >     #15 0x000000bf00000002 in ?? ()
>     >     >     #16 0x37cf558c1298d1e7 in ?? ()
>     >     >     #17 0x0135682800000000 in ?? ()
>     >     >     #18 0x02e00a0e020d0336 in ?? ()
>     >     >     #19 0x0487888c03b90d10 in ?? ()
>     >     >     #20 0x062618da0556e126 in ?? ()
>     >     >     #21 0x0000000006f31067 in ?? ()
>     >     >     #22 0x0000000000000000 in ?? ()
>     >     >
>     >     >
>     >     >
>     >     >
>     >     > --
>     >     > Michael Schuster
>     >     > http://recursiveramblings.wordpress.com/
>     <http://recursiveramblings.wordpress.com/>;
>     >     <http://recursiveramblings.wordpress.com/
>     <http://recursiveramblings.wordpress.com/>>;
>     >     > recursion, n: see 'recursion'
>     >
>     >     --
>     >     Per olof Ljungmark
>     >     +46 707 50 20 46 <tel:%2B46%20707%2050%2020%2046>
>     <tel:%2B46%20707%2050%2020%2046>
>     >     Nethead AB
>     >     Registered in Stockholm, Sweden
>     >     SE556815226701
>     >
>     >
>     >
>     >
>     > --
>     > Michael Schuster
>     > http://recursiveramblings.wordpress.com/
>     <http://recursiveramblings.wordpress.com/>;
>     > recursion, n: see 'recursion'
> 
>     --
>     Per olof Ljungmark
>     +46 707 50 20 46 <tel:%2B46%20707%2050%2020%2046>
>     Nethead AB
>     Registered in Stockholm, Sweden
>     SE556815226701
> 
> 
> 
> 
> -- 
> Michael Schuster
> http://recursiveramblings.wordpress.com/
> recursion, n: see 'recursion'

-- 
Per olof Ljungmark
+46 707 50 20 46
Nethead AB
Registered in Stockholm, Sweden
SE556815226701



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