Date: Thu, 15 Feb 2018 10:27:23 +0100 From: Per olof Ljungmark <peo@nethead.se> To: Michael Schuster <michaelsprivate@gmail.com> Cc: FreeBSD Mailing List <freebsd-questions@freebsd.org> Subject: Re: which limit is hit here? Message-ID: <e29cfb8e-c199-4b5c-7580-71646c807a52@nethead.se> In-Reply-To: <CADqw_g%2BQ0=jbqD9wnYnprXtrUvcz5Lg8AHGMmNrHO8K-UthOgQ@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>
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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@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>>> 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
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