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Selvin Xavier 6a89b3a67a RDMA/bnxt_re: Fix recursive lock warning in debug kernel [ Upstream commit `d455f29f6d` ] Fix possible recursive lock warning. Its a false warning as the locks are part of two differnt HW Queue data structure - cmdq and creq. Debug kernel is throwing the following warning and stack trace. [ 783.914967] ============================================ [ 783.914970] WARNING: possible recursive locking detected [ 783.914973] 4.19.0-rc2+ #33 Not tainted [ 783.914976] -------------------------------------------- [ 783.914979] swapper/2/0 is trying to acquire lock: [ 783.914982] 000000002aa3949d (&(&hwq->lock)->rlock){..-.}, at: bnxt_qplib_service_creq+0x232/0x350 [bnxt_re] [ 783.914999] but task is already holding lock: [ 783.915002] 00000000be73920d (&(&hwq->lock)->rlock){..-.}, at: bnxt_qplib_service_creq+0x2a/0x350 [bnxt_re] [ 783.915013] other info that might help us debug this: [ 783.915016] Possible unsafe locking scenario: [ 783.915019] CPU0 [ 783.915021] ---- [ 783.915034] lock(&(&hwq->lock)->rlock); [ 783.915035] lock(&(&hwq->lock)->rlock); [ 783.915037] * DEADLOCK * [ 783.915038] May be due to missing lock nesting notation [ 783.915039] 1 lock held by swapper/2/0: [ 783.915040] #0: 00000000be73920d (&(&hwq->lock)->rlock){..-.}, at: bnxt_qplib_service_creq+0x2a/0x350 [bnxt_re] [ 783.915044] stack backtrace: [ 783.915046] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.19.0-rc2+ #33 [ 783.915047] Hardware name: Dell Inc. PowerEdge R730/0599V5, BIOS 1.0.4 08/28/2014 [ 783.915048] Call Trace: [ 783.915049] <IRQ> [ 783.915054] dump_stack+0x90/0xe3 [ 783.915058] __lock_acquire+0x106c/0x1080 [ 783.915061] ? sched_clock+0x5/0x10 [ 783.915063] lock_acquire+0xbd/0x1a0 [ 783.915065] ? bnxt_qplib_service_creq+0x232/0x350 [bnxt_re] [ 783.915069] _raw_spin_lock_irqsave+0x4a/0x90 [ 783.915071] ? bnxt_qplib_service_creq+0x232/0x350 [bnxt_re] [ 783.915073] bnxt_qplib_service_creq+0x232/0x350 [bnxt_re] [ 783.915078] tasklet_action_common.isra.17+0x197/0x1b0 [ 783.915081] __do_softirq+0xcb/0x3a6 [ 783.915084] irq_exit+0xe9/0x100 [ 783.915085] do_IRQ+0x6a/0x120 [ 783.915087] common_interrupt+0xf/0xf [ 783.915088] </IRQ> Use nested notation for the spin_lock to avoid this warning. Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2018-11-13 11:08:33 -08:00
arch	KVM: nVMX: Clear reserved bits of #DB exit qualification	2018-11-13 11:08:32 -08:00
block	block, bfq: correctly charge and reset entity service in all cases	2018-11-13 11:08:28 -08:00
certs	export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR()	2018-08-22 23:21:44 +09:00
crypto	Revert "net: simplify sock_poll_wait"	2018-11-04 14:50:51 +01:00
Documentation	Code of Conduct: Change the contact email address	2018-10-22 07:33:36 +01:00
drivers	RDMA/bnxt_re: Fix recursive lock warning in debug kernel	2018-11-13 11:08:33 -08:00
firmware	kbuild: remove all dummy assignments to obj-	2017-11-18 11:46:06 +09:00
fs	f2fs: fix to account IO correctly for cgroup writeback	2018-11-13 11:08:31 -08:00
include	UAPI: ndctl: Fix g++-unsupported initialisation in headers	2018-11-13 11:08:32 -08:00
init	Kbuild updates for v4.19 (2nd)	2018-08-25 13:40:38 -07:00
ipc	ipc/shm.c: use ERR_CAST() for shm_lock() error return	2018-10-05 16:32:04 -07:00
kernel	bpf/verifier: fix verifier instability	2018-11-13 11:08:28 -08:00
lib	locking/lockdep: Fix debug_locks off performance problem	2018-11-13 11:08:20 -08:00
LICENSES	LICENSES: Remove CC-BY-SA-4.0 license text	2018-10-18 11:28:50 +02:00
mm	mremap: properly flush TLB before releasing the page	2018-10-18 11:30:52 +02:00
net	cgroup, netclassid: add a preemption point to write_classid	2018-11-13 11:08:31 -08:00
samples	samples: disable CONFIG_SAMPLES for UML	2018-10-11 02:15:46 +09:00
scripts	Kbuild fixes for v4.19 (2nd)	2018-10-11 19:23:07 +02:00
security	Revert "uapi/linux/keyctl.h: don't use C++ reserved keyword as a struct member name"	2018-09-25 13:28:58 +02:00
sound	ALSA: hda - Fix incorrect clearance of thinkpad_acpi hooks	2018-11-13 11:08:19 -08:00
tools	perf tests: Fix record+probe_libc_inet_pton.sh without ping's debuginfo	2018-11-13 11:08:28 -08:00
usr	initramfs: move gen_initramfs_list.sh from scripts/ to usr/	2018-08-22 23:21:44 +09:00
virt	KVM: Remove obsolete kvm_unmap_hva notifier backend	2018-09-07 15:06:02 +02:00
.clang-format	clang-format: Set IndentWrappedFunctionNames false	2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes	.gitattributes: set git diff driver for C source code files	2016-10-07 18:46:30 -07:00
.gitignore	Kbuild updates for v4.17 (2nd)	2018-04-15 17:21:30 -07:00
.mailmap	libnvdimm-for-4.19_misc	2018-08-25 18:13:10 -07:00
COPYING	COPYING: use the new text with points to the license files	2018-03-23 12:41:45 -06:00
CREDITS	9p: remove Ron Minnich from MAINTAINERS	2018-08-17 16:20:26 -07:00
Kbuild	Kbuild updates for v4.15	2017-11-17 17:45:29 -08:00
Kconfig	kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt	2018-08-02 08:06:55 +09:00
MAINTAINERS	MAINTAINERS: Add an entry for the code of conduct	2018-10-22 07:33:36 +01:00
Makefile	Linux 4.19.1	2018-11-04 14:50:54 +01:00
README	Docs: Added a pointer to the formatted docs to README	2018-03-21 09:02:53 -06:00

README

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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.