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x86/mm/tlb: Also remove local CPU from mm_cpumask if stale

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The code in flush_tlb_func() that removes a remote CPU from the
cpumask if it is no longer running the target mm is also needed
on the originating CPU of a TLB flush, now that CPUs are no
longer cleared from the mm_cpumask at context switch time.

Flushing the TLB when we are not running the target mm is
harmless, because the CPU's tlb_gen only gets updated to
match the mm_tlb_gen, but it does hit this warning:

        WARN_ON_ONCE(local_tlb_gen > mm_tlb_gen);

  [ 210.343902][ T4668] WARNING: CPU: 38 PID: 4668 at arch/x86/mm/tlb.c:815 flush_tlb_func (arch/x86/mm/tlb.c:815)

Removing both local and remote CPUs from the mm_cpumask
when doing a flush for a not currently loaded mm avoids
that warning.

Reported-by: kernel test robot <oliver.sang@intel.com>
Tested-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20241205104630.755706ca@fangorn
Closes: https://lore.kernel.org/oe-lkp/202412051551.690e9656-lkp@intel.com
This commit is contained in:
Rik van Riel 2024-12-05 10:46:30 -05:00 committed by Ingo Molnar
parent 2815a56e4b
commit 953753db88
1 changed files with 6 additions and 6 deletions
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12
arch/x86/mm/tlb.c
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@ -756,13 +756,13 @@ static void flush_tlb_func(void *info)
if (!local) {
inc_irq_stat(irq_tlb_count);
count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED);
}
/* Can only happen on remote CPUs */
if (f->mm && f->mm != loaded_mm) {
cpumask_clear_cpu(raw_smp_processor_id(), mm_cpumask(f->mm));
trace_tlb_flush(TLB_REMOTE_WRONG_CPU, 0);
return;
}
/* The CPU was left in the mm_cpumask of the target mm. Clear it. */
if (f->mm && f->mm != loaded_mm) {
cpumask_clear_cpu(raw_smp_processor_id(), mm_cpumask(f->mm));
trace_tlb_flush(TLB_REMOTE_WRONG_CPU, 0);
return;
}
if (unlikely(loaded_mm == &init_mm))