linux/drivers/infiniband
Jason Gunthorpe a4e63bce14 RDMA/odp: Ensure the mm is still alive before creating an implicit child
Registration of a mmu_notifier requires the caller to hold a mmget() on
the mm as registration is not permitted to race with exit_mmap(). There is
a BUG_ON inside the mmu_notifier to guard against this.

Normally creating a umem is done against current which implicitly holds
the mmget(), however an implicit ODP child is created from a pagefault
work queue and is not guaranteed to have a mmget().

Call mmget() around this registration and abort faulting if the MM has
gone to exit_mmap().

Before the patch below the notifier was registered when the implicit ODP
parent was created, so there was no chance to register a notifier outside
of current.

Fixes: c571feca2d ("RDMA/odp: use mmu_notifier_get/put for 'struct ib_ucontext_per_mm'")
Link: https://lore.kernel.org/r/20200227114118.94736-1-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2020-03-04 13:56:07 -04:00
..
core RDMA/odp: Ensure the mm is still alive before creating an implicit child 2020-03-04 13:56:07 -04:00
hw IB/mlx5: Fix implicit ODP race 2020-03-04 13:25:00 -04:00
sw RDMA/rxe: Fix soft lockup problem due to using tasklets in softirq 2020-02-13 10:51:09 -04:00
ulp RDMA subsystem updates for 5.6 2020-01-31 14:40:36 -08:00
Kconfig RDMA/iw_cxgb3: Remove the iw_cxgb3 module from kernel 2019-10-04 15:08:59 -03:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00