Revision - a4e63bc - RDMA/odp: Ensure the mm is still alive before creating an [...] - origin: https://github.com/torvalds/linux

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Revision a4e63bce1414df7ab6eb82ca9feb8494ce13e554 authored by Jason Gunthorpe on 27 February 2020, 11:41:18 UTC, committed by Jason Gunthorpe on 04 March 2020, 17:56:07 UTC

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: c571feca2dc9 ("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>

1 parent e38b55e

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Tip revision: a4e63bce1414df7ab6eb82ca9feb8494ce13e554 authored by Jason Gunthorpe on 27 February 2020, 11:41:18 UTC
RDMA/odp: Ensure the mm is still alive before creating an implicit child

Tip revision: a4e63bc

File	Mode	Size
Documentation
LICENSES
arch
block
certs
crypto
drivers
fs
include
init
ipc
kernel
lib
mm
net
samples
scripts
security
sound
tools
usr
virt
.clang-format	-rw-r--r--	15.0 KB
.cocciconfig	-rw-r--r--	59 bytes
.get_maintainer.ignore	-rw-r--r--	71 bytes
.gitattributes	-rw-r--r--	62 bytes
.gitignore	-rw-r--r--	1.7 KB
.mailmap	-rw-r--r--	14.8 KB
COPYING	-rw-r--r--	423 bytes
CREDITS	-rw-r--r--	97.3 KB
Kbuild	-rw-r--r--	1.3 KB
Kconfig	-rw-r--r--	595 bytes
MAINTAINERS	-rw-r--r--	532.9 KB
Makefile	-rw-r--r--	58.9 KB
README	-rw-r--r--	727 bytes

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RDMA/odp: Ensure the mm is still alive before creating an implicit child

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