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Thomas Gleixner
84393817db
Larry reported a CPU hotplug lock recursion in the MTRR code.
============================================
WARNING: possible recursive locking detected
systemd-udevd/153 is trying to acquire lock:
(cpu_hotplug_lock.rw_sem){.+.+.+}, at: [<c030fc26>] stop_machine+0x16/0x30
but task is already holding lock:
(cpu_hotplug_lock.rw_sem){.+.+.+}, at: [<c0234353>] mtrr_add_page+0x83/0x470
....
cpus_read_lock+0x48/0x90
stop_machine+0x16/0x30
mtrr_add_page+0x18b/0x470
mtrr_add+0x3e/0x70
mtrr_add_page() holds the hotplug rwsem already and calls stop_machine()
which acquires it again.
Call stop_machine_cpuslocked() instead.
Reported-and-tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1708140920250.1865@nanos
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@suse.de>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. 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.