linux-kernel - [PATCH] ocfs2: fix memory leak in ocfs2_mount

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Message-ID: <20221108152516.1189165-1-lizetao1@huawei.com>
Date:   Tue, 8 Nov 2022 23:25:16 +0800
From:   Li Zetao <lizetao1@...wei.com>
To:     <mark@...heh.com>, <jlbec@...lplan.org>,
        <joseph.qi@...ux.alibaba.com>, <srinivas.eeda@...cle.com>
CC:     <lizetao1@...wei.com>, <ocfs2-devel@....oracle.com>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH] ocfs2: fix memory leak in ocfs2_mount_volume()

There is a memory leak reported by kmemleak:

  unreferenced object 0xffff88810cc65e60 (size 32):
    comm "mount.ocfs2", pid 23753, jiffies 4302528942 (age 34735.105s)
    hex dump (first 32 bytes):
      10 00 00 00 00 00 00 00 00 01 01 01 01 01 01 01  ................
      01 01 01 01 01 01 01 01 00 00 00 00 00 00 00 00  ................
    backtrace:
      [<ffffffff8170f73d>] __kmalloc+0x4d/0x150
      [<ffffffffa0ac3f51>] ocfs2_compute_replay_slots+0x121/0x330 [ocfs2]
      [<ffffffffa0b65165>] ocfs2_check_volume+0x485/0x900 [ocfs2]
      [<ffffffffa0b68129>] ocfs2_mount_volume.isra.0+0x1e9/0x650 [ocfs2]
      [<ffffffffa0b7160b>] ocfs2_fill_super+0xe0b/0x1740 [ocfs2]
      [<ffffffff818e1fe2>] mount_bdev+0x312/0x400
      [<ffffffff819a086d>] legacy_get_tree+0xed/0x1d0
      [<ffffffff818de82d>] vfs_get_tree+0x7d/0x230
      [<ffffffff81957f92>] path_mount+0xd62/0x1760
      [<ffffffff81958a5a>] do_mount+0xca/0xe0
      [<ffffffff81958d3c>] __x64_sys_mount+0x12c/0x1a0
      [<ffffffff82f26f15>] do_syscall_64+0x35/0x80
      [<ffffffff8300006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

This call stack is related to two problems. Firstly, the ocfs2 super uses
"replay_map" to trace online/offline slots, in order to recover offline
slots during recovery and mount. But when ocfs2_truncate_log_init()
returns an error in ocfs2_mount_volume(), the memory of "replay_map"
will not be freed in error handling path. Secondly, the memory of
"replay_map" will not be freed if d_make_root() returns an error in
ocfs2_fill_super(). But the memory of "replay_map" will be freed normally
when completing recovery and mount in ocfs2_complete_mount_recovery().

Fix the first problem by adding error handling path to free "replay_map"
when ocfs2_truncate_log_init() fails. And fix the second problem by
calling ocfs2_free_replay_slots(osb) in the error handling path
"out_dismount". In addition, since ocfs2_free_replay_slots() is static,
it is necessary to remove its static attribute and declare it in header
file.

Fixes: 9140db04ef18 ("ocfs2: recover orphans in offline slots during recovery and mount")
Signed-off-by: Li Zetao <lizetao1@...wei.com>
---
 fs/ocfs2/journal.c | 2 +-
 fs/ocfs2/journal.h | 1 +
 fs/ocfs2/super.c   | 5 ++++-
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index 126671e6caed..3fb98b4569a2 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -157,7 +157,7 @@ static void ocfs2_queue_replay_slots(struct ocfs2_super *osb,
 	replay_map->rm_state = REPLAY_DONE;
 }
 
-static void ocfs2_free_replay_slots(struct ocfs2_super *osb)
+void ocfs2_free_replay_slots(struct ocfs2_super *osb)
 {
 	struct ocfs2_replay_map *replay_map = osb->replay_map;
 
diff --git a/fs/ocfs2/journal.h b/fs/ocfs2/journal.h
index 969d0aa28718..41c382f68529 100644
--- a/fs/ocfs2/journal.h
+++ b/fs/ocfs2/journal.h
@@ -150,6 +150,7 @@ int ocfs2_recovery_init(struct ocfs2_super *osb);
 void ocfs2_recovery_exit(struct ocfs2_super *osb);
 
 int ocfs2_compute_replay_slots(struct ocfs2_super *osb);
+void ocfs2_free_replay_slots(struct ocfs2_super *osb);
 /*
  *  Journal Control:
  *  Initialize, Load, Shutdown, Wipe a journal.
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 42c993e53924..f8041aebe4ee 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -1159,6 +1159,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
 out_dismount:
 	atomic_set(&osb->vol_state, VOLUME_DISABLED);
 	wake_up(&osb->osb_mount_event);
+	ocfs2_free_replay_slots(osb);
 	ocfs2_dismount_volume(sb, 1);
 	goto out;
 
@@ -1822,12 +1823,14 @@ static int ocfs2_mount_volume(struct super_block *sb)
 	status = ocfs2_truncate_log_init(osb);
 	if (status < 0) {
 		mlog_errno(status);
-		goto out_system_inodes;
+		goto out_truncate_log;
 	}
 
 	ocfs2_super_unlock(osb, 1);
 	return 0;
 
+out_truncate_log:
+	ocfs2_free_replay_slots(osb);
 out_system_inodes:
 	if (osb->local_alloc_state == OCFS2_LA_ENABLED)
 		ocfs2_shutdown_local_alloc(osb);
-- 
2.25.1