From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ajay Kaher Subject: [PATCH v4 2/3][v4.9.y] coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping Date: Tue, 25 Jun 2019 02:33:04 +0530 Message-ID: <1561410186-3919-2-git-send-email-akaher@vmware.com> References: <1561410186-3919-1-git-send-email-akaher@vmware.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1561410186-3919-1-git-send-email-akaher@vmware.com> Sender: stable-owner@vger.kernel.org To: aarcange@redhat.com, jannh@google.com, oleg@redhat.com, peterx@redhat.com, rppt@linux.ibm.com, jgg@mellanox.com, mhocko@suse.com Cc: jglisse@redhat.com, akpm@linux-foundation.org, mike.kravetz@oracle.com, viro@zeniv.linux.org.uk, riandrews@android.com, arve@android.com, yishaih@mellanox.com, dledford@redhat.com, sean.hefty@intel.com, hal.rosenstock@gmail.com, matanb@mellanox.com, leonro@mellanox.com, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, devel@driverdev.osuosl.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, akaher@vmware.com, srivatsab@vmware.com, amakhalov@vmware.com List-Id: linux-rdma@vger.kernel.org This patch is the extension of following upstream commit to fix the race condition between get_task_mm() and core dumping for IB->mlx4 and IB->mlx5 drivers: commit 04f5866e41fb ("coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping")' Thanks to Jason for pointing this. Signed-off-by: Ajay Kaher --- drivers/infiniband/hw/mlx4/main.c | 4 +++- drivers/infiniband/hw/mlx5/main.c | 3 +++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/hw/mlx4/main.c b/drivers/infiniband/hw/mlx4/main.c index 8d59a59..7ccf722 100644 --- a/drivers/infiniband/hw/mlx4/main.c +++ b/drivers/infiniband/hw/mlx4/main.c @@ -1172,6 +1172,8 @@ static void mlx4_ib_disassociate_ucontext(struct ib_ucontext *ibcontext) * mlx4_ib_vma_close(). */ down_write(&owning_mm->mmap_sem); + if (!mmget_still_valid(owning_mm)) + goto skip_mm; for (i = 0; i < HW_BAR_COUNT; i++) { vma = context->hw_bar_info[i].vma; if (!vma) @@ -1190,7 +1192,7 @@ static void mlx4_ib_disassociate_ucontext(struct ib_ucontext *ibcontext) /* context going to be destroyed, should not access ops any more */ context->hw_bar_info[i].vma->vm_ops = NULL; } - +skip_mm: up_write(&owning_mm->mmap_sem); mmput(owning_mm); put_task_struct(owning_process); diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c index b1daf5c..f94df0e 100644 --- a/drivers/infiniband/hw/mlx5/main.c +++ b/drivers/infiniband/hw/mlx5/main.c @@ -1307,6 +1307,8 @@ static void mlx5_ib_disassociate_ucontext(struct ib_ucontext *ibcontext) * mlx5_ib_vma_close. */ down_write(&owning_mm->mmap_sem); + if (!mmget_still_valid(owning_mm)) + goto skip_mm; list_for_each_entry_safe(vma_private, n, &context->vma_private_list, list) { vma = vma_private->vma; @@ -1321,6 +1323,7 @@ static void mlx5_ib_disassociate_ucontext(struct ib_ucontext *ibcontext) list_del(&vma_private->list); kfree(vma_private); } +skip_mm: up_write(&owning_mm->mmap_sem); mmput(owning_mm); put_task_struct(owning_process); -- 2.7.4