which limit is hit here?

[Per olof Ljungmark]

On 02/15/18 10:31, Michael Schuster wrote:
> 
> 
> On Thu, Feb 15, 2018 at 10:27 AM, Per olof Ljungmark <peo at nethead.se
> <mailto:peo at 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.

>  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 at nethead.se <mailto:peo at nethead.se>
>     > <mailto:peo at nethead.se <mailto:peo at 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 at nethead.se <mailto:peo at nethead.se> <mailto:peo at nethead.se
>     <mailto:peo at nethead.se>>
>     >     > <mailto:peo at nethead.se <mailto:peo at nethead.se>
>     <mailto:peo at nethead.se <mailto:peo at 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/>
>     > 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