which limit is hit here?

[Per olof Ljungmark]

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."

> 
> On Thu, Feb 15, 2018 at 10:06 AM, Per olof Ljungmark <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>>> 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/
> recursion, n: see 'recursion'

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