Hi, we're having constant issues with CIFS mounts on our Linux terminal servers (Ubuntu 12.04 with updated kernel). Usually after 1 or 2 days we see the following in dmesg: [63840.116062] INFO: task cifsiod:1393 blocked for more than 120 seconds. [63840.116101] Not tainted 3.19.0-7-generic #7-Ubuntu [63840.116135] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [63840.116175] cifsiod D ffff88079ba3fbb8 0 1393 2 0x00000000 [63840.116193] Workqueue: cifsiod cifs_oplock_break [cifs] [63840.116195] ffff88079ba3fbb8 ffff880799305850 0000000000014200 ffff88079ba3ffd8 [63840.116197] 0000000000014200 ffff8804c3cdd850 ffff880799305850 ffff88079c7971c0 [63840.116198] ffff8807bfc94af8 ffff8807bff995e8 0000000000000002 ffffffff817cb0d0 [63840.116200] Call Trace: [63840.116207] [<ffffffff817cb0d0>] ? bit_wait_timeout+0x70/0x70 [63840.116209] [<ffffffff817ca800>] io_schedule+0xa0/0x130 [63840.116210] [<ffffffff817cb0fb>] bit_wait_io+0x2b/0x50 [63840.116212] [<ffffffff817caca7>] __wait_on_bit+0x67/0x90 [63840.116215] [<ffffffff8117ba00>] ? find_get_pages_tag+0x110/0x190 [63840.116217] [<ffffffff8117a645>] wait_on_page_bit+0xc5/0xd0 [63840.116220] [<ffffffff810b6f70>] ? autoremove_wake_function+0x40/0x40 [63840.116221] [<ffffffff8117a739>] filemap_fdatawait_range+0xe9/0x180 [63840.116225] [<ffffffff810a0070>] ? sched_ttwu_pending+0x70/0x70 [63840.116227] [<ffffffff8117a7f7>] filemap_fdatawait+0x27/0x30 [63840.116232] [<ffffffffc049fb31>] cifs_oplock_break+0x301/0x330 [cifs] [63840.116234] [<ffffffff8108f218>] process_one_work+0x158/0x460 [63840.116236] [<ffffffff8108f6ac>] rescuer_thread+0x18c/0x460 [63840.116237] [<ffffffff8108f520>] ? process_one_work+0x460/0x460 [63840.116239] [<ffffffff810950e9>] kthread+0xc9/0xe0 [63840.116241] [<ffffffff81095020>] ? kthread_create_on_node+0x1c0/0x1c0 [63840.116243] [<ffffffff817cf2bc>] ret_from_fork+0x7c/0xb0 [63840.116244] [<ffffffff81095020>] ? kthread_create_on_node+0x1c0/0x1c0 The same repeats for various other processes like kworker and the hanging userspace process. This happens with all recent kernel versions (3.13-3.19) and forces us to reboot the server regularly as the requesting processes always hang with process state "D" and (I/O) load increases from day to day. Further information: Mount options: sec=krb5,multiuser,mfsymlinks,dir_mode=0700,file_mode=0700,nomapposix,noserverino,cache=loose,nobrl CIFS server: Samba 4.1.17 with default configuration We can't use cache=strict as it causes problems with certain userspace programs. I was hoping ca7df8e0bb2a5ec79691de8a1a4c0e611fe04e60 fixes the issue but apparently it does not. Is there anything else we can try or examine? Best regards Tobias -- Dipl.-Inf. Tobias Doerffel ----------------------------------------------- EDC Electronic Design Chemnitz GmbH Technologie-Campus 4, 09126 Chemnitz Geschäftsführer: Dr.-Ing. Steffen Heinz Dipl.-Ing. André Lange Tel.: +49 371 52 45 90 Fax.: +49 371 52 45 910 E-Mail: info@xxxxxxxxxxxxxx Sitz der Gesellschaft: Chemnitz HRB 23986, Amtsgericht Chemnitz USTID: DE258181725 ----------------------------------------------- -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html