diff options
| author |   Rik van Riel <riel@surriel.com> | 2024-12-05 10:46:30 -0500 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2024-12-06 10:25:53 +0100 |
| commit | 953753db887f9d70f70f61d6ecbe5cf209107672 (patch) | |
| tree | cf7767890d97be7a22263826306ed2d2434bf6d3 | |
| parent | x86/mm/tlb: Add tracepoint for TLB flush IPI to stale CPU (diff) | |
| download | wireguard-linux-953753db887f9d70f70f61d6ecbe5cf209107672.tar.xz wireguard-linux-953753db887f9d70f70f61d6ecbe5cf209107672.zip | |
x86/mm/tlb: Also remove local CPU from mm_cpumask if stale
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
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/mm/tlb.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 1aac4fa90d3d..3c30817ec6a2 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -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)) |