[PATCH v2 2/2] nvmet: avoid memleak by freeing any remaining aens in nvmet_async_events_free

From: David Milburn <dmilburn@redhat.com>
To: linux-nvme@lists.infradead.org
Cc: hch@infradead.org, chaitanya.kulkarni@wdc.com, dwagner@suse.de
Subject: [PATCH v2 2/2] nvmet: avoid memleak by freeing any remaining aens in nvmet_async_events_free
Date: Mon, 18 May 2020 13:59:56 -0500	[thread overview]
Message-ID: <1589828396-144513-3-git-send-email-dmilburn@redhat.com> (raw)
In-Reply-To: <1589828396-144513-1-git-send-email-dmilburn@redhat.com>

Make sure we free all resources including any remaining aens
which may result in a memory leak.

$ cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff888c1af2c000 (size 32):
  comm "nvmetcli", pid 5164, jiffies 4295220864 (age 6829.924s)
  hex dump (first 32 bytes):
    28 01 82 3b 8b 88 ff ff 28 01 82 3b 8b 88 ff ff  (..;....(..;....
    02 00 04 65 76 65 6e 74 5f 66 69 6c 65 00 00 00  ...event_file...
  backtrace:
    [<00000000217ae580>] nvmet_add_async_event+0x57/0x290 [nvmet]
    [<0000000012aa2ea9>] nvmet_ns_changed+0x206/0x300 [nvmet]
    [<00000000bb3fd52e>] nvmet_ns_disable+0x367/0x4f0 [nvmet]
    [<00000000e91ca9ec>] nvmet_ns_free+0x15/0x180 [nvmet]
    [<00000000a15deb52>] config_item_release+0xf1/0x1c0
    [<000000007e148432>] configfs_rmdir+0x555/0x7c0
    [<00000000f4506ea6>] vfs_rmdir+0x142/0x3c0
    [<0000000000acaaf0>] do_rmdir+0x2b2/0x340
    [<0000000034d1aa52>] do_syscall_64+0xa5/0x4d0
    [<00000000211f13bc>] entry_SYSCALL_64_after_hwframe+0x6a/0xdf

Steps to Reproduce:

target:
1. nvmetcli restore rdma.json

client:
2. nvme connect -t rdma -a $IP -s 4420 -n testnqn

target:
3. nvmetcli clear
4. sleep 5 && nvmetcli restore rdma.json
5. cat /sys/kernel/debug/kmemleak after 5 minutes

Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: David Milburn <dmilburn@redhatcom>
---
Changes from v1:
 - declare struct nvmet_async_event in this patch.

 drivers/nvme/target/core.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index dc036a815d39..dda888672f31 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -154,6 +154,7 @@ static void nvmet_async_events_process(struct nvmet_ctrl *ctrl, u16 status)
 
 static void nvmet_async_events_free(struct nvmet_ctrl *ctrl)
 {
+	struct nvmet_async_event *aen;
 	struct nvmet_req *req;
 
 	mutex_lock(&ctrl->lock);
@@ -163,6 +164,13 @@ static void nvmet_async_events_free(struct nvmet_ctrl *ctrl)
 		nvmet_req_complete(req, NVME_SC_INTERNAL | NVME_SC_DNR);
 		mutex_lock(&ctrl->lock);
 	}
+
+	while (!list_empty(&ctrl->async_events)) {
+		aen = list_first_entry(&ctrl->async_events,
+				       struct nvmet_async_event, entry);
+		list_del(&aen->entry);
+		kfree(aen);
+	}
 	mutex_unlock(&ctrl->lock);
 }
 
-- 
2.18.1


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