diff options
| author | Douglas Miller <doug.miller@cornelisnetworks.com> | 2022-04-08 09:35:23 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-13 21:01:08 +0200 |
| commit | 5f54364ff6cfcd14cddf5441c4a490bb28dd69f7 (patch) | |
| tree | 0b72e43139e05e842fc983d4f3819f08f76c47d5 /drivers/infiniband | |
| parent | 8bb41682911f8d3d0874af6646406856290565a9 (diff) | |
RDMA/hfi1: Fix use-after-free bug for mm struct
commit 2bbac98d0930e8161b1957dc0ec99de39ade1b3c upstream.
Under certain conditions, such as MPI_Abort, the hfi1 cleanup code may
represent the last reference held on the task mm.
hfi1_mmu_rb_unregister() then drops the last reference and the mm is freed
before the final use in hfi1_release_user_pages(). A new task may
allocate the mm structure while it is still being used, resulting in
problems. One manifestation is corruption of the mmap_sem counter leading
to a hang in down_write(). Another is corruption of an mm struct that is
in use by another task.
Fixes: 3d2a9d642512 ("IB/hfi1: Ensure correct mm is used at all times")
Link: https://lore.kernel.org/r/20220408133523.122165.72975.stgit@awfm-01.cornelisnetworks.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Douglas Miller <doug.miller@cornelisnetworks.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/infiniband')
| -rw-r--r-- | drivers/infiniband/hw/hfi1/mmu_rb.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/infiniband/hw/hfi1/mmu_rb.c b/drivers/infiniband/hw/hfi1/mmu_rb.c index d213f65d4cdd..ed8a96ae61ce 100644 --- a/drivers/infiniband/hw/hfi1/mmu_rb.c +++ b/drivers/infiniband/hw/hfi1/mmu_rb.c @@ -121,6 +121,9 @@ void hfi1_mmu_rb_unregister(struct mmu_rb_handler *handler) unsigned long flags; struct list_head del_list; + /* Prevent freeing of mm until we are completely finished. */ + mmgrab(handler->mn.mm); + /* Unregister first so we don't get any more notifications. */ mmu_notifier_unregister(&handler->mn, handler->mn.mm); @@ -143,6 +146,9 @@ void hfi1_mmu_rb_unregister(struct mmu_rb_handler *handler) do_remove(handler, &del_list); + /* Now the mm may be freed. */ + mmdrop(handler->mn.mm); + kfree(handler); } |