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Stefan Wiehler
9da397e5d4
commit55702ec960upstream. rcutree_report_cpu_starting() must be called before clockevents_register_device() to avoid the following lockdep splat triggered by calling list_add() when CONFIG_PROVE_RCU_LIST=y: WARNING: suspicious RCU usage ... ----------------------------- kernel/locking/lockdep.c:3680 RCU-list traversed in non-reader section!! other info that might help us debug this: RCU used illegally from offline CPU! rcu_scheduler_active = 1, debug_locks = 1 no locks held by swapper/1/0. ... Call Trace: [<ffffffff8012a434>] show_stack+0x64/0x158 [<ffffffff80a93d98>] dump_stack_lvl+0x90/0xc4 [<ffffffff801c9e9c>] __lock_acquire+0x1404/0x2940 [<ffffffff801cbf3c>] lock_acquire+0x14c/0x448 [<ffffffff80aa4260>] _raw_spin_lock_irqsave+0x50/0x88 [<ffffffff8021e0c8>] clockevents_register_device+0x60/0x1e8 [<ffffffff80130ff0>] r4k_clockevent_init+0x220/0x3a0 [<ffffffff801339d0>] start_secondary+0x50/0x3b8 raw_smp_processor_id() is required in order to avoid calling into lockdep before RCU has declared the CPU to be watched for readers. See also commit29368e0939("x86/smpboot: Move rcu_cpu_starting() earlier"), commitde5d9dae15("s390/smp: move rcu_cpu_starting() earlier") and commit99f070b623("powerpc/smp: Call rcu_cpu_starting() earlier"). Signed-off-by: Stefan Wiehler <stefan.wiehler@nokia.com> Reviewed-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.