Hi guys, I'm sorry if someone else has already asked the same question before, but here's what we are facing with scsi mid-level.
Variables of bit-field in struct scsi_device are not protected by lock, such as no_report_opcodes, is_visible and so on. I guess everyone think these variable can't be accessed by multi-processes, but unfortunately, I came across one problem as follows: Assuming there is a process A which is executing the operation of adding device, so it will call scsi_sysfs_add_sdev, and eventually it will start an async kworker B to execute sd_probe_async. In this way, process A will set "sdev->is_visible = 1" in the function of scsi_sysfs_add_sdev, in the meantime, aysnc kworker B may set "sdev->no_report_opcodes = 1" in the function of sd_read_write_same. Neither of the variables are protected by any lock, setting the value of no_report_opcodes may change value of is_visible from 1 to 0, which alters the bit field unexpectedly. Did I miss anything? So I'd like to know whether these variable of bit-field should be protected by lock or not. Please advise. Thanks in advance! Best regards, Yiwen -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
