There is a known Problem with epoll, at least on Red Hat / CentOS, this bugzilla may give you additional info (comments of Timo inside)
https://bugzilla.redhat.com/show_bug.cgi?id=681578 Regards Javier El 30/05/2012 17:45, Konrad . escribió: > When we upgrade our kernels from 2.6.32.2 to 3.2.16 something strange > has happened. > On high traffic dovecot/auth looks like not responding. > > We found a lot of this lines at the log: > dovecot: pop3-login: Error: net_connect_unix(pop3) failed: Resource > temporarily unavailable > (...) and clients stop authorizing > > Some other errors follow in the wake of: > dovecot: pop3: Error: Raw backtrace: > /opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x373ca) [0x7768a3ca] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x3743b) [0x7768a43b] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(i_fatal+0) [0x7766048b] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x4593a) [0x7769893a] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(io_add+0xaf) [0x7769757f] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(master_service_init_finish+0x19a) > [0x77683c2a] -> dovecot/pop3(main+0xfc) [0x804a90c] -> > /lib/i386-linux-gnu/libc.so.6(__libc_start_main+0xf3) [0x774c04d3] -> > dovecot/pop3() [0x804aba9] > dovecot: pop3: Error: Raw backtrace: > /opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x373ca) [0x7768a3ca] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x3743b) [0x7768a43b] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(i_fatal+0) [0x7766048b] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x4593a) [0x7769893a] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(io_add+0xaf) [0x7769757f] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(master_service_init_finish+0x19a) > [0x77683c2a] -> dovecot/pop3(main+0xfc) [0x804a90c] -> > /lib/i386-linux-gnu/libc.so.6(__libc_start_main+0xf3) [0x774c04d3] -> > dovecot/pop3() [0x804aba9] > dovecot: master: Error: service(pop3): child 18756 killed with signal > 6 (core dumped) > dovecot: master: Error: service(pop3): child 18756 killed with signal > 6 (core dumped) > dovecot: master: Error: service(pop3): command startup failed, throttling > dovecot: master: Error: service(pop3): command startup failed, throttling > dovecot: pop3-login: Error: Raw backtrace: > /opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x373ca) [0x776b73ca] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x3743b) [0x776b743b] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(i_fatal+0) [0x7768d48b] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x4593a) [0x776c593a] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(io_add+0xaf) [0x776c457f] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(master_service_init_finish+0x19a) > [0x776b0c2a] -> > /opt/dovecot2/lib/dovecot/libdovecot-login.so.0(main+0x143) > [0x77705383] -> /lib/i386-linux-gnu/libc.so.6(__libc_start_main+0xf3) > [0x774ed4d3] -> dovecot/pop3-login() [0x8049471] > dovecot: pop3-login: Error: Raw backtrace: > /opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x373ca) [0x776fd3ca] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x3743b) [0x776fd43b] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(i_fatal+0) [0x776d348b] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x4593a) [0x7770b93a] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(io_add+0xaf) [0x7770a57f] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(master_service_init_finish+0x19a) > [0x776f6c2a] -> > /opt/dovecot2/lib/dovecot/libdovecot-login.so.0(main+0x143) > [0x7774b383] -> /lib/i386-linux-gnu/libc.so.6(__libc_start_main+0xf3) > [0x775334d3] -> dovecot/pop3-login() [0x8049471] > > And example stack trace (from pop3, pop3-login throws almost the same): > #0 0x776f6424 in __kernel_vsyscall () > No symbol table info available. > #1 0x7744d1ef in __GI_raise (sig=6) at > ../nptl/sysdeps/unix/sysv/linux/raise.c:64 > resultvar = > resultvar = > pid = 2002518004 > selftid = 25476 > #2 0x77450835 in __GI_abort () at abort.c:91 > save_stage = 2 > act = {__sigaction_handler = {sa_handler = 0x9bce4a8, > sa_sigaction = 0x9bce4a8}, sa_mask = {__val = {163409408, 2002781570, > 163374248, 603, 163374280, > 604, 163374280, 2001703379, 0, 2002790760, 2140717252, > 163374280, 0, 2003786736, 2002596704, 0, 2002618953, 2003087348, > 2140717196, 0, 163409408, > 2001286473, 163374248, 10, 2000834616, 2002534400, 604, > 2003087348, 604, 2002791863, 4294967295, 10}}, sa_flags = 2140717316, > sa_restorer = 0x7764bd84 } > sigs = {__val = {32, 0 }} > #3 0x77603390 in default_fatal_finish (type=, > status=) at failures.c:187 > backtrace = 0x9bce098 > "/opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x3837a) [0x7760337a] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(+0x383eb) [0x776033eb] -> > /opt/dovecot2/lib/dovecot/libdovecot.so.0(i_fatal+0) [0x775d877a"... > #4 0x776033eb in i_internal_fatal_handler (ctx=0x7f98c174, > format=0x9bd6db0 "(25476) epoll_ctl(%s, %d) failed: %m", > args=0x7f98c194 "\323bw06") > at failures.c:688 > status = 0 > #5 0x775d877a in i_panic (format=0x7762d364 "epoll_ctl(%s, %d) > failed: %m") at failures.c:263 > ctx = {type = LOG_TYPE_PANIC, exit_status = 0, timestamp = 0x0} > args = 0x7f98c194 "\323bw06" > f = > #6 0x77611d8a in io_loop_handle_add (io=0x9bd6d78) at ioloop-epoll.c:119 > ---Type to continue, or q to quit--- > ctx = 0x9bd64d8 > list = > event = {events = 24, data = {ptr = 0x9bd6da0, fd = 163409312, > u32 = 163409312, u64 = 163409312}} > op = 1 > first = true > #7 0x776109af in io_add (fd=6, condition=IO_ERROR, > callback=0x775fd030 , context=0x9bd6300) at > ioloop.c:54 > io = > __FUNCTION__ = "io_add" > #8 0x775fca9a in master_service_init_finish (service=0x9bd6300) at > master-service.c:381 > sigint_flags = > st = {st_dev = 8, __pad1 = 0, __st_ino = 1286567453, st_mode = > 4480, st_nlink = 1, st_uid = 0, st_gid = 0, st_rdev = 0, __pad2 = 0, > st_size = 0, > st_blksize = 4096, st_blocks = 0, st_atim = {tv_sec = > 1338389522, tv_nsec = 269436805}, st_mtim = {tv_sec = 1338389522, > tv_nsec = 269436805}, st_ctim = { > tv_sec = 1338389522, tv_nsec = 269436805}, st_ino = 1286567453} > value = > count = 1 > __FUNCTION__ = "master_service_init_finish" > #9 0x0804a954 in main (argc=1, argv=0x7f98c414) at main.c:232 > set_roots = {0x804ee40, 0x0} > service_flags = > storage_service_flags = MAIL_STORAGE_SERVICE_FLAG_DISALLOW_ROOT > postlogin_socket_path = 0x0 > username = 0x0 > c = > > We do some investigation. > Restart helped for a moment, but problem was returning. > When we back to older kernel - everything back to normal. > > We compile Dovecot with poll instead of epoll (--with-ioloop=poll) and > this works for us. > > Is any problem with epoll on 3.2.x kernels? Or maybe this is Dovecot problem? > Maybe this is not connected with epoll, but epoll is interferes with this. > > Problem on Dovecot 2.0.11 and 2.0.20.
