1.2.3 Segfaulting on RHEL 5 (x86_64) with -P option & threads enabled

[Paul Lindner]

This has been fixed in HEAD.  I ran into this preparing the fedora
builds too.  

------------------------------------------------------------------------
r604 | plindner | 2007-08-06 10:58:40 -0700 (Mon, 06 Aug 2007) | 3
lines

Workaround crash when using -P and -d flags on x86_64 with latest
libevent release.


On Mon, Oct 01, 2007 at 01:14:17PM -0400, Brendan W. McAdams wrote:
> Kind of weird: we're using the EPEL build [memcached-1.2.3-4.el5], but I
> also built from scratch and get the same issue.  On 4 brand new machines
> (Dell Poweredge 1950s, RHEL 5, 8 gigs RAM, 2xQuad-Core Intel(R) Xeon(R) CPU
> L5320  @ 1.86GHz), we get segfaults after memcached writes the PID file:
> 
> memcached[5634]: segfault at 0000000000007889 rip 0000003583c03223 rsp
> 00007fff63cd5698 error 4
> memcached[5651]: segfault at 0000000000007889 rip 0000003583c03223 rsp
> 00007fff24b1e4d8 error 4
> memcached[5734]: segfault at 0000000000007889 rip 0000003583c03223 rsp
> 00007ffff51ae7a8 error 4
> 
> 
> I played with options taking things in and out, and it's definitely the PID
> (-P) option:the file writes, contains a PID but it looks like write after
> it's written memcached fails.  If I remove the -P option, the server starts
> up cleanly and runs fine.  Also played with memory allocation and max
> connections, but it's definitely the PID option...
> 
> 
> Here's the relevant Strace output:
> 
> 
> mmap(NULL, 528384, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
> 0x2aaaaacc4000
> rt_sigaction(SIGPIPE, {SIG_IGN}, NULL, 8) = 0
> epoll_ctl(4, EPOLL_CTL_ADD, 3, {EPOLLIN, {u32=487064496, u64=487064496}}) =
> 0
> open("/var/run/memcached/memcached.pid", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 7
> fstat(7, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
> mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
> 0x2aaaaad45000
> write(7, "10070\n", 6)                  = 6
> close(7)                                = 0
> munmap(0x2aaaaad45000, 4096)            = 0
> pipe([7, 8])                            = 0
> epoll_ctl(4, EPOLL_CTL_ADD, 7, {EPOLLIN, {u32=487064560, u64=487064560}}) =
> 0
> pipe([9, 10])                           = 0
> getrlimit(RLIMIT_NOFILE, {rlim_cur=1024, rlim_max=1024}) = 0
> epoll_create(1024)                      = 11
> fcntl(11, F_SETFD, FD_CLOEXEC)          = 0
> socketpair(PF_FILE, SOCK_STREAM, 0, [12, 13]) = 0
> fcntl(12, F_SETFD, FD_CLOEXEC)          = 0
> fcntl(13, F_SETFD, FD_CLOEXEC)          = 0
> epoll_ctl(11, EPOLL_CTL_ADD, 9, {EPOLLIN, {u32=487107392, u64=487107392}}) =
> 0
> pipe([14, 15])                          = 0
> Process 10070 detached
> 
> Just as I was about to send this I had a thought, and tried something else:
> IF I build without --enable-threads -P works fine.  I haven't played with
> 1.2.2 yet as I'm trying to get these machines online and into production for
> a release, but any insight into what's doing this would be great.  These
> machines are basically stock RedHat 5, with lighttpd pulled from EPEL.

-- 
Paul Lindner        ||||| | | | |  |  |  |   |   |
lindner at inuus.com
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