Date: Thu, 15 Feb 2018 10:06:02 +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: <71635f3b-0494-1956-fa31-bd8df7b72a93@nethead.se> In-Reply-To: <CADqw_gKS=%2Be=PCgG6OJVfbuSwWD4zioZ__gnVNc5hYtM2Mfo%2Bg@mail.gmail.com> References: <d4d1093d-0db2-baed-0fb5-04b5127c8ccb@nethead.se> <CADqw_gKS=%2Be=PCgG6OJVfbuSwWD4zioZ__gnVNc5hYtM2Mfo%2Bg@mail.gmail.com>
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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>> 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 ?? ()
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