Patch "infiniband: fix race condition between infiniband mlx4, mlx5 driver and core dumping" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    infiniband: fix race condition between infiniband mlx4, mlx5  driver and core dumping

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     infiniband-fix-race-condition-between-infiniband-mlx4-mlx5-driver-and-core-dumping.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From akaher@vmware.com  Mon Aug  5 08:01:12 2019
From: Ajay Kaher <akaher@vmware.com>
Date: Sun, 4 Aug 2019 09:29:26 +0530
Subject: infiniband: fix race condition between infiniband mlx4, mlx5  driver and core dumping
To: <aarcange@redhat.com>, <jannh@google.com>, <oleg@redhat.com>, <peterx@redhat.com>, <rppt@linux.ibm.com>, <jgg@mellanox.com>, <mhocko@suse.com>
Cc: srinidhir@vmware.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, amakhalov@vmware.com, sean.hefty@intel.com, srivatsa@csail.mit.edu, srivatsab@vmware.com, devel@driverdev.osuosl.org, linux-rdma@vger.kernel.org, bvikas@vmware.com, dledford@redhat.com, akaher@vmware.com, riandrews@android.com, hal.rosenstock@gmail.com, vsirnapalli@vmware.com, leonro@mellanox.com, jglisse@redhat.com, viro@zeniv.linux.org.uk, gregkh@linuxfoundation.org, yishaih@mellanox.com, matanb@mellanox.com, stable@vger.kernel.org, arve@android.com, linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org, torvalds@linux-foundation.org, mike.kravetz@oracle.com
Message-ID: <1564891168-30016-2-git-send-email-akaher@vmware.com>

From: Ajay Kaher <akaher@vmware.com>

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 <akaher@vmware.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/infiniband/hw/mlx4/main.c |    4 +++-
 drivers/infiniband/hw/mlx5/main.c |    3 +++
 2 files changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/hw/mlx4/main.c
+++ b/drivers/infiniband/hw/mlx4/main.c
@@ -1172,6 +1172,8 @@ static void mlx4_ib_disassociate_ucontex
 	 * 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_ucontex
 		/* 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);
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -1307,6 +1307,8 @@ static void mlx5_ib_disassociate_ucontex
 	 * 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_ucontex
 		list_del(&vma_private->list);
 		kfree(vma_private);
 	}
+skip_mm:
 	up_write(&owning_mm->mmap_sem);
 	mmput(owning_mm);
 	put_task_struct(owning_process);


Patches currently in stable-queue which might be from akaher@vmware.com are

queue-4.9/infiniband-fix-race-condition-between-infiniband-mlx4-mlx5-driver-and-core-dumping.patch
queue-4.9/coredump-fix-race-condition-between-collapse_huge_page-and-core-dumping.patch
queue-4.9/coredump-fix-race-condition-between-mmget_not_zero-get_task_mm-and-core-dumping.patch