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eea2d396aa
Fix the following lockdep warning:
============================================
WARNING: possible recursive locking detected
5.4.0-rc6-dbg+ #2 Not tainted
--------------------------------------------
systemd-udevd/130 is trying to acquire lock:
ffffffff826b05d0 (cpu_hotplug_lock.rw_sem){++++}, at: irq_calc_affinity_vectors+0x63/0x90
but task is already holding lock:
ffffffff826b05d0 (cpu_hotplug_lock.rw_sem){++++}, at: lpfc_sli4_enable_intr+0x422/0xd50 [lpfc]
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(cpu_hotplug_lock.rw_sem);
lock(cpu_hotplug_lock.rw_sem);
*** DEADLOCK ***
May be due to missing lock nesting notation
2 locks held by systemd-udevd/130:
#0: ffff8880d53fe210 (&dev->mutex){....}, at: __device_driver_lock+0x4a/0x70
#1: ffffffff826b05d0 (cpu_hotplug_lock.rw_sem){++++}, at: lpfc_sli4_enable_intr+0x422/0xd50 [lpfc]
stack backtrace:
CPU: 1 PID: 130 Comm: systemd-udevd Not tainted 5.4.0-rc6-dbg+ #2
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Call Trace:
dump_stack+0xa5/0xe6
__lock_acquire.cold+0xf7/0x23a
lock_acquire+0x106/0x240
cpus_read_lock+0x41/0xe0
irq_calc_affinity_vectors+0x63/0x90
__pci_enable_msix_range+0x10a/0x950
pci_alloc_irq_vectors_affinity+0x144/0x210
lpfc_sli4_enable_intr+0x4b2/0xd50 [lpfc]
lpfc_pci_probe_one+0x1411/0x22b0 [lpfc]
local_pci_probe+0x7c/0xc0
pci_device_probe+0x25d/0x390
really_probe+0x170/0x510
driver_probe_device+0x127/0x190
device_driver_attach+0x98/0xa0
__driver_attach+0xb6/0x1a0
bus_for_each_dev+0x100/0x150
driver_attach+0x31/0x40
bus_add_driver+0x246/0x300
driver_register+0xe0/0x170
__pci_register_driver+0xde/0xf0
lpfc_init+0x134/0x1000 [lpfc]
do_one_initcall+0xda/0x47e
do_init_module+0x10a/0x3b0
load_module+0x4318/0x47c0
__do_sys_finit_module+0x134/0x1d0
__x64_sys_finit_module+0x47/0x50
do_syscall_64+0x6f/0x2e0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fixes: dcaa213679 ("scsi: lpfc: Change default IRQ model on AMD architectures")
Link: https://lore.kernel.org/r/20191107052158.25788-4-bvanassche@acm.org
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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.