WSL2-Linux-Kernel/drivers/target/iscsi
Nicholas Bellinger 978d13d60c iscsi-target: Fix iscsi_np reset hung task during parallel delete
This patch fixes a bug associated with iscsit_reset_np_thread()
that can occur during parallel configfs rmdir of a single iscsi_np
used across multiple iscsi-target instances, that would result in
hung task(s) similar to below where configfs rmdir process context
was blocked indefinately waiting for iscsi_np->np_restart_comp
to finish:

[ 6726.112076] INFO: task dcp_proxy_node_:15550 blocked for more than 120 seconds.
[ 6726.119440]       Tainted: G        W  O     4.1.26-3321 #2
[ 6726.125045] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 6726.132927] dcp_proxy_node_ D ffff8803f202bc88     0 15550      1 0x00000000
[ 6726.140058]  ffff8803f202bc88 ffff88085c64d960 ffff88083b3b1ad0 ffff88087fffeb08
[ 6726.147593]  ffff8803f202c000 7fffffffffffffff ffff88083f459c28 ffff88083b3b1ad0
[ 6726.155132]  ffff88035373c100 ffff8803f202bca8 ffffffff8168ced2 ffff8803f202bcb8
[ 6726.162667] Call Trace:
[ 6726.165150]  [<ffffffff8168ced2>] schedule+0x32/0x80
[ 6726.170156]  [<ffffffff8168f5b4>] schedule_timeout+0x214/0x290
[ 6726.176030]  [<ffffffff810caef2>] ? __send_signal+0x52/0x4a0
[ 6726.181728]  [<ffffffff8168d7d6>] wait_for_completion+0x96/0x100
[ 6726.187774]  [<ffffffff810e7c80>] ? wake_up_state+0x10/0x10
[ 6726.193395]  [<ffffffffa035d6e2>] iscsit_reset_np_thread+0x62/0xe0 [iscsi_target_mod]
[ 6726.201278]  [<ffffffffa0355d86>] iscsit_tpg_disable_portal_group+0x96/0x190 [iscsi_target_mod]
[ 6726.210033]  [<ffffffffa0363f7f>] lio_target_tpg_store_enable+0x4f/0xc0 [iscsi_target_mod]
[ 6726.218351]  [<ffffffff81260c5a>] configfs_write_file+0xaa/0x110
[ 6726.224392]  [<ffffffff811ea364>] vfs_write+0xa4/0x1b0
[ 6726.229576]  [<ffffffff811eb111>] SyS_write+0x41/0xb0
[ 6726.234659]  [<ffffffff8169042e>] system_call_fastpath+0x12/0x71

It would happen because each iscsit_reset_np_thread() sets state
to ISCSI_NP_THREAD_RESET, sends SIGINT, and then blocks waiting
for completion on iscsi_np->np_restart_comp.

However, if iscsi_np was active processing a login request and
more than a single iscsit_reset_np_thread() caller to the same
iscsi_np was blocked on iscsi_np->np_restart_comp, iscsi_np
kthread process context in __iscsi_target_login_thread() would
flush pending signals and only perform a single completion of
np->np_restart_comp before going back to sleep within transport
specific iscsit_transport->iscsi_accept_np code.

To address this bug, add a iscsi_np->np_reset_count and update
__iscsi_target_login_thread() to keep completing np->np_restart_comp
until ->np_reset_count has reached zero.

Reported-by: Gary Guo <ghg@datera.io>
Tested-by: Gary Guo <ghg@datera.io>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2017-08-06 14:41:41 -07:00
..
cxgbit cxgbit: fix sg_nents calculation 2017-07-30 15:35:34 -07:00
Kconfig cxgbit: add files for cxgbit.ko 2016-05-09 23:12:54 -07:00
Makefile cxgbit: add files for cxgbit.ko 2016-05-09 23:12:54 -07:00
iscsi_target.c iscsi-target: Fix iscsi_np reset hung task during parallel delete 2017-08-06 14:41:41 -07:00
iscsi_target.h target: Minimize #include directives 2016-12-09 10:22:28 -08:00
iscsi_target_auth.c iscsi: ensure RNG is seeded before use 2017-06-19 22:06:28 -04:00
iscsi_target_auth.h target: Minimize #include directives 2016-12-09 10:22:28 -08:00
iscsi_target_configfs.c iscsi-target: Add login_keys_workaround attribute for non RFC initiators 2017-07-11 10:56:39 -07:00
iscsi_target_datain_values.c target: Minimize #include directives 2016-12-09 10:22:28 -08:00
iscsi_target_datain_values.h target: Minimize #include directives 2016-12-09 10:22:28 -08:00
iscsi_target_device.c target: Fix max_cmd_sn increment w/o cmdsn mutex regressions 2015-09-11 00:32:28 -07:00
iscsi_target_device.h target: Minimize #include directives 2016-12-09 10:22:28 -08:00
iscsi_target_erl0.c iscsi-target: Always wait for kthread_should_stop() before kthread exit 2017-05-31 15:12:57 -07:00
iscsi_target_erl0.h iscsi-target: Always wait for kthread_should_stop() before kthread exit 2017-05-31 15:12:57 -07:00
iscsi_target_erl1.c target: Minimize #include directives 2016-12-09 10:22:28 -08:00
iscsi_target_erl1.h target: Minimize #include directives 2016-12-09 10:22:28 -08:00
iscsi_target_erl2.c target/iscsi: Fix spelling of "reallegiance" 2017-02-09 00:39:08 -08:00
iscsi_target_erl2.h target/iscsi: Fix spelling of "reallegiance" 2017-02-09 00:39:08 -08:00
iscsi_target_login.c iscsi-target: Fix iscsi_np reset hung task during parallel delete 2017-08-06 14:41:41 -07:00
iscsi_target_login.h target: Minimize #include directives 2016-12-09 10:22:28 -08:00
iscsi_target_nego.c iscsi-target: Add login_keys_workaround attribute for non RFC initiators 2017-07-11 10:56:39 -07:00
iscsi_target_nego.h target: Minimize #include directives 2016-12-09 10:22:28 -08:00
iscsi_target_nodeattrib.c iscsi-target: Move iscsi_target_[core,stat].h under linux include 2015-01-30 13:06:21 -08:00
iscsi_target_nodeattrib.h target: Minimize #include directives 2016-12-09 10:22:28 -08:00
iscsi_target_parameters.c iscsi-target: Add login_keys_workaround attribute for non RFC initiators 2017-07-11 10:56:39 -07:00
iscsi_target_parameters.h iscsi-target: Add login_keys_workaround attribute for non RFC initiators 2017-07-11 10:56:39 -07:00
iscsi_target_seq_pdu_list.c iscsi-target: Move iscsi_target_[core,stat].h under linux include 2015-01-30 13:06:21 -08:00
iscsi_target_seq_pdu_list.h target: Minimize #include directives 2016-12-09 10:22:28 -08:00
iscsi_target_stat.c target: use per-attribute show and store methods 2015-10-13 22:17:49 -07:00
iscsi_target_tmr.c target/iscsi: Fix spelling of "reallegiance" 2017-02-09 00:39:08 -08:00
iscsi_target_tmr.h target: Minimize #include directives 2016-12-09 10:22:28 -08:00
iscsi_target_tpg.c iscsi-target: Add login_keys_workaround attribute for non RFC initiators 2017-07-11 10:56:39 -07:00
iscsi_target_tpg.h iscsi-target: Add login_keys_workaround attribute for non RFC initiators 2017-07-11 10:56:39 -07:00
iscsi_target_transport.c target: Minimize #include directives 2016-12-09 10:22:28 -08:00
iscsi_target_util.c target/iscsi: Simplify iscsit_free_cmd() 2017-07-06 23:11:27 -07:00
iscsi_target_util.h target/iscsi: Remove second argument of __iscsit_free_cmd() 2017-07-06 23:11:26 -07:00