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Thomas reported the following warning:
BUG: using smp_processor_id() in preemptible [00000000] code: ovsdb-server/4498
caller is native_flush_tlb_single+0x57/0xc0
native_flush_tlb_single+0x57/0xc0
__set_pte_vaddr+0x2d/0x40
set_pte_vaddr+0x2f/0x40
cea_set_pte+0x30/0x40
ds_update_cea.constprop.4+0x4d/0x70
reserve_ds_buffers+0x159/0x410
x86_reserve_hardware+0x150/0x160
x86_pmu_event_init+0x3e/0x1f0
perf_try_init_event+0x69/0x80
perf_event_alloc+0x652/0x740
SyS_perf_event_open+0x3f6/0xd60
do_syscall_64+0x5c/0x190
set_pte_vaddr is used to map the ds buffers into the cpu entry area, but
there are two problems with that:
1) The resulting flush is not supposed to be called in preemptible context
2) The cpu entry area is supposed to be per CPU, but the debug store
buffers are mapped for all CPUs so these mappings need to be flushed
globally.
Add the necessary preemption protection across the mapping code and flush
TLBs globally.
Fixes: c1961a4631da ("x86/events/intel/ds: Map debug buffers in cpu_entry_area")
Reported-by: Thomas Zeitlhofer <thomas.zeitlhofer+lkml@ze-it.at>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Thomas Zeitlhofer <thomas.zeitlhofer+lkml@ze-it.at>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180104170712.GB3040@hirez.programming.kicks-ass.net
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.