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CPU1: Sets a valid sbdf via devid_write, then checks the sbdf's > validity in execution flows such as devid_show, iommu_devtbl_show, > and iommu_irqtbl_show. > > 2. CPU2: Sets an invalid sbdf via devid_write, at which point the sbdf > value is -1. > > 3. CPU1: accesses the IOMMU device table, IRQ table, based on the > invalid SBDF value of -1, resulting in illegal access. > > This is especially problematic in monitoring scripts, where multiple > scripts may access debugFS simultaneously, and some scripts may > unexpectedly set invalid values, which triggers illegal access in > debugfs. > > This patch modifies the execution flow of devid_show, > iommu_devtbl_show, and iommu_irqtbl_show to ensure that these > processes determine the validity and access based on the > same device-id, thus guaranteeing correctness and robustness. > Signed-off-by: Guanghui Feng Looks good. Reviewed-by: Vasant Hegde -Vasant