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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 在 2025/2/20 18:15, Yunhui Cui 写道: > When entering intel_iommu_shutdown, system interrupts are disabled, System interrupts were disabled ? you mean all interrupts were disabled when entering intel_iommu_shutdown(), perhaps it is not true, at least for upstream latest code. > and the reboot process might be scheduled out by down_write(). If the > scheduled process does not yield (e.g., while(1)), the system will hang. No NMI lockup watchdog jumping out here ? Thanks, Ethan > > Signed-off-by: Yunhui Cui > --- > drivers/iommu/intel/iommu.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c > index cc46098f875b..76a1d83b46bf 100644 > --- a/drivers/iommu/intel/iommu.c > +++ b/drivers/iommu/intel/iommu.c > @@ -2871,7 +2871,8 @@ void intel_iommu_shutdown(void) > if (no_iommu || dmar_disabled) > return; > > - down_write(&dmar_global_lock); > + if (!down_write_trylock(&dmar_global_lock)) > + return; > > /* Disable PMRs explicitly here. */ > for_each_iommu(iommu, drhd) -- "firm, enduring, strong, and long-lived"