b5bbc65512
HW may generate completions that indicates QP is destroyed.
Driver should not be scheduling any more completion handlers
for this QP, after the QP is destroyed. Since CQs are active
during the QP destroy, driver may still schedule completion
handlers. This can cause a race where the destroy_cq and poll_cq
running simultaneously.
Snippet of kernel panic while doing bnxt_re driver load unload in loop.
This indicates a poll after the CQ is freed.
[77786.481636] Call Trace:
[77786.481640] <TASK>
[77786.481644] bnxt_re_poll_cq+0x14a/0x620 [bnxt_re]
[77786.481658] ? kvm_clock_read+0x14/0x30
[77786.481693] __ib_process_cq+0x57/0x190 [ib_core]
[77786.481728] ib_cq_poll_work+0x26/0x80 [ib_core]
[77786.481761] process_one_work+0x1e5/0x3f0
[77786.481768] worker_thread+0x50/0x3a0
[77786.481785] ? __pfx_worker_thread+0x10/0x10
[77786.481790] kthread+0xe2/0x110
[77786.481794] ? __pfx_kthread+0x10/0x10
[77786.481797] ret_from_fork+0x2c/0x50
To avoid this, complete all completion handlers before returning the
destroy QP. If free_cq is called soon after destroy_qp, IB stack
will cancel the CQ work before invoking the destroy_cq verb and
this will prevent any race mentioned.
Fixes: 1ac5a4047975 ("RDMA/bnxt_re: Add bnxt_re RoCE driver")
Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Link: https://lore.kernel.org/r/1689322969-25402-2-git-send-email-selvin.xavier@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.