Date: Mon, 17 Mar 2014 18:44:56 +0000 From: Karl Pielorz <kpielorz_lst@tdx.co.uk> To: =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= <roger.pau@citrix.com>, freebsd-xen@FreeBSD.org Subject: Re: FBSD 10.0-S (r261289M) under XenServer 6.2 - Stuck sshd in urdlck? Message-ID: <6534613783544E26A15CF44F@study64.tdx.co.uk> In-Reply-To: <53272E41.3050409@citrix.com> References: <4B8380EBE379080FAD3271FA@Mail-PC.tdx.co.uk> <53272E41.3050409@citrix.com>
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--On 17 March 2014 18:17:53 +0100 Roger Pau Monn=C3=A9 = <roger.pau@citrix.com>=20 wrote: >> Anyone know what 'urdlck' is? > > It seems like the process is stuck while trying to acquire a rw mutex in > read mode. Could you obtain a backtrace of the process with gdb? Ok, I think I did this right - let me know if I've not... # gdb /usr/sbin/sshd 5325 ... Attaching to program: /usr/sbin/sshd, process 5325 warning: current_sos: Can't read pathname for load map: Bad address [repeated several times] [lots of reading symbols from - 'no debugging symbols found' output] ... [New Thread 804006400 (LWP 100184/sshd)] [a few reading symbols - 'no debugging symbols found' output] Loaded symbols for /libexec/ld-elf.so.1 [Switching to Thread 804006400 (LWP 100184/sshd)] 0x00000008038eb89c in __error () from /lib/libthr.so.3 (gdb) bt #0 0x00000008038eb89c in __error () from /lib/libthr.so.3 #1 0x00000008038e921c in pthread_timedjoin_np () from /lib/libthr.so.3 #2 0x000000080064f9a2 in _rtld_get_stack_prot () from /libexec/ld-elf.so.1 #3 0x00000008006498c9 in r_debug_state () from /libexec/ld-elf.so.1 #4 0x00000008006470cd in .text () from /libexec/ld-elf.so.1 #5 0x0000000000000246 in ?? () #6 0x0000000000000000 in ?? () " > Also a > kernel-space dump might be useful, could you also run procstat -k <pid>? procstat output is: " # procstat -k 5334 PID TID COMM TDNAME KSTACK 5334 100183 sshd - mi_switch=20 sleepq_catch_signals sleepq_wait_sig _sleep umtxq_sleep do_rw_rdlock=20 __umtx_op_rw_rdlock amd64_syscall Xfast_syscall " If you can briefly tell me how to do the kernel-space dump? Do I panic the=20 machine (i.e. cause a crash-dump?) somehow? Cheers & thanks for your reply, -Karl
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