Commit 3d2825c8 authored Aug 27, 2020 by Alexander Aring Committed by David Teigland Aug 27, 2020

fs: dlm: fix configfs memory leak



This patch fixes the following memory detected by kmemleak and umount
gfs2 filesystem which removed the last lockspace:

unreferenced object 0xffff9264f482f600 (size 192):
  comm "dlm_controld", pid 325, jiffies 4294690276 (age 48.136s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 6e 6f 64 65 73 00 00 00  ........nodes...
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000060481d7>] make_space+0x41/0x130
    [<000000008d905d46>] configfs_mkdir+0x1a2/0x5f0
    [<00000000729502cf>] vfs_mkdir+0x155/0x210
    [<000000000369bcf1>] do_mkdirat+0x6d/0x110
    [<00000000cc478a33>] do_syscall_64+0x33/0x40
    [<00000000ce9ccf01>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

The patch just remembers the "nodes" entry pointer in space as I think
it's created as subdirectory when parent "spaces" is created. In
function drop_space() we will lost the pointer reference to nds because
configfs_remove_default_groups(). However as this subdirectory is always
available when "spaces" exists it will just be freed when "spaces" will be
freed.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

parent 043697f0

fs/dlm/config.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -221,6 +221,7 @@ struct dlm_space {
		struct list_head members;
		struct mutex members_lock;
		int members_count;
		struct dlm_nodes *nds;
		};

		struct dlm_comms {
		@@ -430,6 +431,7 @@ static struct config_group make_space(struct config_group g, const char *name)
		INIT_LIST_HEAD(&sp->members);
		mutex_init(&sp->members_lock);
		sp->members_count = 0;
		sp->nds = nds;
		return &sp->group;

		fail:
		@@ -451,6 +453,7 @@ static void drop_space(struct config_group g, struct config_item i)
		static void release_space(struct config_item *i)
		{
		struct dlm_space *sp = config_item_to_space(i);
		kfree(sp->nds);
		kfree(sp);
		}

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