| commit | 10c39de26c1356d088f2dbaa5809e1289062641d | |
| author | Matthew Dillon <dillon@apollo.backplane.com> | |
| Mon, 5 Sep 2016 19:33:42 +0000 (5 12:33 -0700) | ||
| committer | Matthew Dillon <dillon@apollo.backplane.com> | |
| Mon, 5 Sep 2016 19:33:42 +0000 (5 12:33 -0700) | ||
| tree | 461bd4db62a93ebc08ba5dfecc2a51be7ecefbc0 | treesnapshot (tar.gz zip) |
| parent | 295428701a38864138373ee27033fb7a9fc09814 | commitdiff |
kernel - Fix indefinite wait buffer during heavy swapping
* Fix a deadlock which can occur between CAM and the VM system due to
a bug in uiomove_nofault() when called via vop_helper_read_shortcut().
If the backing store is swapped out, vm_fault()/vm_fault_object() attempts
to page the data in instead of telling uiomove_nofault() to give up.
This can result in a deadlock against the underlying vm_page's in the
file that might already be undergoing I/O.
* Probably also reported by other people over the years, but could never
track it down until now.
Reported-by: Studbolt
* Fix a deadlock which can occur between CAM and the VM system due to
a bug in uiomove_nofault() when called via vop_helper_read_shortcut().
If the backing store is swapped out, vm_fault()/vm_fault_object() attempts
to page the data in instead of telling uiomove_nofault() to give up.
This can result in a deadlock against the underlying vm_page's in the
file that might already be undergoing I/O.
* Probably also reported by other people over the years, but could never
track it down until now.
Reported-by: Studbolt
| sys/vm/vm_fault.c | diffblobblamehistory |