On 4/19/22 16:28, Wenchao Hao wrote:
Hi all, I am wondered how does SCSI EH guarantee there is no UAF of scsi_cmnd
if host reset failed. If host reset failed and eh_cmd_q of shost is not empty,
these command in eh_cmd_q would be added to done_q in scsi_eh_offline_sdevs()
and finished by scsi_eh_flush_done_q(). So these scsi_cmnd and it's related
request would be freed.
Yes.
While since host reset failed, we can not guarantee the LLDDs has cleared all
references to these commands in eh_cmd_q. Is there any possibility that the
LLDDs reference to these commands? If this happened, then a using after free
issue would occur.
If host reset has failed there are _no_ assumptions we can make about
commands, and not even about the PCI device itself.
So in effect, once host_reset failed the system is hosed.
We _might_ be able to resurrect the system by doing PCI EEH, but not
many systems nor drivers implement that.
Cheers,
Hannes
