Messages in this thread | | | Date | Fri, 1 Jul 2011 10:05:31 -0700 | From | Andi Kleen <> | Subject | Linux 3.0 oopses when pulling a USB CDROM |
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Hi,
I found I can reliably crash a 3.0 system by pulling the USB cable of a mounted USB cdrom (or rather a USB device which has a builtin fake CD-ROM)
I suspect it's a regression too.
It ends with a NULL pointer reference on a NULL sdev in scsi_prep_state_check.
Here's a somewhat incomplete backtrace (written down by hand)
scsi_prep_state_check scsi_setup_blk_pc_cmnd blk_peek_request ... scsi_request_fn ... ioctl_internal_command ... scsi_set_medium_removal sr_lock_door cdrom_release ... umount
I tried adding a
if (!sdev) return BLKPREP_KILL;
to scsi_prep_state_check, but that caused a RCU CPU stall and a generally unhappy system instead.
The sdev must be still there in scsi_set_medium_removal because it's referenced, so it must get lost somewhere in SCSI or in the block layer.
Any ideas how to fix this?
-Andi -- ak@linux.intel.com -- Speaking for myself only
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