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author | Steve Sistare <steven.sistare@oracle.com> | 2023-01-31 08:58:04 -0800 |
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committer | Alex Williamson <alex.williamson@redhat.com> | 2023-02-09 11:39:14 -0700 |
commit | 046eca5018f8a5dd1dc2cedf87fb5843b9ea3026 (patch) | |
tree | bb4f28348e7ac703569d12aa7b247897a9fa8c2a /scripts | |
parent | ef3a3f6a294ba65fd906a291553935881796f8a5 (diff) | |
download | linux-stable-046eca5018f8a5dd1dc2cedf87fb5843b9ea3026.tar.gz linux-stable-046eca5018f8a5dd1dc2cedf87fb5843b9ea3026.tar.bz2 linux-stable-046eca5018f8a5dd1dc2cedf87fb5843b9ea3026.zip |
vfio/type1: prevent underflow of locked_vm via exec()
When a vfio container is preserved across exec, the task does not change,
but it gets a new mm with locked_vm=0, and loses the count from existing
dma mappings. If the user later unmaps a dma mapping, locked_vm underflows
to a large unsigned value, and a subsequent dma map request fails with
ENOMEM in __account_locked_vm.
To avoid underflow, grab and save the mm at the time a dma is mapped.
Use that mm when adjusting locked_vm, rather than re-acquiring the saved
task's mm, which may have changed. If the saved mm is dead, do nothing.
locked_vm is incremented for existing mappings in a subsequent patch.
Fixes: 73fa0d10d077 ("vfio: Type1 IOMMU implementation")
Cc: stable@vger.kernel.org
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/1675184289-267876-3-git-send-email-steven.sistare@oracle.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'scripts')
0 files changed, 0 insertions, 0 deletions