691b048093
- When a iSER session is released, ib_isert module is taking a mutex lock and releasing all pending connections. As part of this, ib_isert is destroying rdma cm_id. To destroy cm_id, rdma_cm module is sending CM events to CMA handler of ib_isert. This handler is taking same mutex lock. Hence it leads to deadlock between ib_isert & rdma_cm modules. - For fix, created local list of pending connections and release the connection outside of mutex lock. Calltrace: --------- [ 1229.791410] INFO: task kworker/10:1:642 blocked for more than 120 seconds. [ 1229.791416] Tainted: G OE --------- - - 4.18.0-372.9.1.el8.x86_64 #1 [ 1229.791418] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 1229.791419] task:kworker/10:1 state:D stack: 0 pid: 642 ppid: 2 flags:0x80004000 [ 1229.791424] Workqueue: ib_cm cm_work_handler [ib_cm] [ 1229.791436] Call Trace: [ 1229.791438] __schedule+0x2d1/0x830 [ 1229.791445] ? select_idle_sibling+0x23/0x6f0 [ 1229.791449] schedule+0x35/0xa0 [ 1229.791451] schedule_preempt_disabled+0xa/0x10 [ 1229.791453] __mutex_lock.isra.7+0x310/0x420 [ 1229.791456] ? select_task_rq_fair+0x351/0x990 [ 1229.791459] isert_cma_handler+0x224/0x330 [ib_isert] [ 1229.791463] ? ttwu_queue_wakelist+0x159/0x170 [ 1229.791466] cma_cm_event_handler+0x25/0xd0 [rdma_cm] [ 1229.791474] cma_ib_handler+0xa7/0x2e0 [rdma_cm] [ 1229.791478] cm_process_work+0x22/0xf0 [ib_cm] [ 1229.791483] cm_work_handler+0xf4/0xf30 [ib_cm] [ 1229.791487] ? move_linked_works+0x6e/0xa0 [ 1229.791490] process_one_work+0x1a7/0x360 [ 1229.791491] ? create_worker+0x1a0/0x1a0 [ 1229.791493] worker_thread+0x30/0x390 [ 1229.791494] ? create_worker+0x1a0/0x1a0 [ 1229.791495] kthread+0x10a/0x120 [ 1229.791497] ? set_kthread_struct+0x40/0x40 [ 1229.791499] ret_from_fork+0x1f/0x40 [ 1229.791739] INFO: task targetcli:28666 blocked for more than 120 seconds. [ 1229.791740] Tainted: G OE --------- - - 4.18.0-372.9.1.el8.x86_64 #1 [ 1229.791741] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 1229.791742] task:targetcli state:D stack: 0 pid:28666 ppid: 5510 flags:0x00004080 [ 1229.791743] Call Trace: [ 1229.791744] __schedule+0x2d1/0x830 [ 1229.791746] schedule+0x35/0xa0 [ 1229.791748] schedule_preempt_disabled+0xa/0x10 [ 1229.791749] __mutex_lock.isra.7+0x310/0x420 [ 1229.791751] rdma_destroy_id+0x15/0x20 [rdma_cm] [ 1229.791755] isert_connect_release+0x115/0x130 [ib_isert] [ 1229.791757] isert_free_np+0x87/0x140 [ib_isert] [ 1229.791761] iscsit_del_np+0x74/0x120 [iscsi_target_mod] [ 1229.791776] lio_target_np_driver_store+0xe9/0x140 [iscsi_target_mod] [ 1229.791784] configfs_write_file+0xb2/0x110 [ 1229.791788] vfs_write+0xa5/0x1a0 [ 1229.791792] ksys_write+0x4f/0xb0 [ 1229.791794] do_syscall_64+0x5b/0x1a0 [ 1229.791798] entry_SYSCALL_64_after_hwframe+0x65/0xca Fixes: bd3792205aae ("iser-target: Fix pending connections handling in target stack shutdown sequnce") Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com> Signed-off-by: Saravanan Vajravel <saravanan.vajravel@broadcom.com> Link: https://lore.kernel.org/r/20230606102531.162967-2-saravanan.vajravel@broadcom.com Signed-off-by: Leon Romanovsky <leon@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.