On 1/9/24 02:56, Kevin Locke wrote: > Hi all, > > On a ThinkPad T430 running Linux 6.7, when I attempt to delete the ATA > device for a hard drive in the Ultrabay slot (to hotswap/undock it[1]) > the process freezes in an unterruptible sleep. Specifically, if I run > > echo 1 >/sys/devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/delete > > The shell process hangs in the write(2) syscall. The last dmesg > entries post hang are: > > sd 1:0:0:0: [sda] Synchronizing SCSI cache > ata2: SATA link up 6.0 Gbps (SStatus 133 SControl 300) > ata2.00: ACPI cmd f5/00:00:00:00:00:a0(SECURITY FREEZE LOCK) filtered out > ata2.00: ACPI cmd ef/10:03:00:00:00:a0(SET FEATURES) filtered out > ata2.00: ACPI cmd f5/00:00:00:00:00:a0(SECURITY FREEZE LOCK) filtered out > ata2.00: ACPI cmd ef/10:03:00:00:00:a0(SET FEATURES) filtered out > ata2.00: configured for UDMA/133 It looks like the device was sleeping or was in standby state. If that is the case, then we may be deadlocking with the scsi revalidate done when waking up a drive. Can you confirm what the power state of the drive was when you ran this ? Do you see an issue if you first make sure that the drive is spun-up ? > ata2.00: retrying FLUSH 0xea Emask 0x0 > > On kernel versions prior to 6.5-rc1, dmesg would subsequently contain: > > sd 1:0:0:0: [sda] Stopping disk > ata2.00: disable device > > Note that the hang only occurs when deleting a hard disk drive. It > does not occur when deleting an optical disk drive. > > I bisected the regression to 8b566edbdbfb5cde31a322c57932694ff48125ed. > > I know very little about the SCSI/ATA subsystems or the internals of > ATA hotswapping/undocking. I'd appreciate any help investigating the > issue, or properly undocking. > > Thanks, > Kevin > > [1]: https://www.thinkwiki.org/wiki/How_to_hotswap_Ultrabay_devices > -- Damien Le Moal Western Digital Research
