block_dev: Suppress bdev_cache_init() kmemleak warninig
Kmemleak reports the following warning in bdev_cache_init()
[ 0.003738] kmemleak: Object 0xffff880153035200 (size 256):
[ 0.003823] kmemleak: comm "swapper/0", pid 0, jiffies 4294667299
[ 0.003909] kmemleak: min_count = 1
[ 0.003988] kmemleak: count = 0
[ 0.004066] kmemleak: flags = 0x1
[ 0.004144] kmemleak: checksum = 0
[ 0.004224] kmemleak: backtrace:
[ 0.004303] [<ffffffff814755ac>] kmemleak_alloc+0x21/0x3e
[ 0.004446] [<ffffffff811100ba>] kmem_cache_alloc+0xca/0x1dc
[ 0.004592] [<ffffffff811371b1>] alloc_vfsmnt+0x1f/0x198
[ 0.004736] [<ffffffff811375c5>] vfs_kern_mount+0x36/0xd2
[ 0.004879] [<ffffffff8113929a>] kern_mount_data+0x18/0x32
[ 0.005025] [<ffffffff81ab9075>] bdev_cache_init+0x51/0x81
[ 0.005169] [<ffffffff81ab8abf>] vfs_caches_init+0x101/0x10d
[ 0.005313] [<ffffffff81a9bae3>] start_kernel+0x344/0x383
[ 0.005456] [<ffffffff81a9b2a7>] x86_64_start_reservations+0xae/0xb2
[ 0.005602] [<ffffffff81a9b3ad>] x86_64_start_kernel+0x102/0x111
[ 0.005747] [<ffffffffffffffff>] 0xffffffffffffffff
[ 0.008653] kmemleak: Trying to color unknown object at 0xffff880153035220 as Grey
[ 0.008754] Pid: 0, comm: swapper/0 Not tainted 3.3.0-rc0-dbg-04200-g8180888-dirty #888
[ 0.008856] Call Trace:
[ 0.008934] [<ffffffff81118704>] ? find_and_get_object+0x44/0x118
[ 0.009023] [<ffffffff81118fe6>] paint_ptr+0x57/0x8f
[ 0.009109] [<ffffffff81475935>] kmemleak_not_leak+0x23/0x42
[ 0.009195] [<ffffffff81ab9096>] bdev_cache_init+0x72/0x81
[ 0.009282] [<ffffffff81ab8abf>] vfs_caches_init+0x101/0x10d
[ 0.009368] [<ffffffff81a9bae3>] start_kernel+0x344/0x383
[ 0.009466] [<ffffffff81a9b2a7>] x86_64_start_reservations+0xae/0xb2
[ 0.009555] [<ffffffff81a9b140>] ? early_idt_handlers+0x140/0x140
[ 0.009643] [<ffffffff81a9b3ad>] x86_64_start_kernel+0x102/0x111
due to attempt to mark pointer to `struct vfsmount' as a gray object, which
is embedded into `struct mount' returned from alloc_vfsmnt().
Make `bd_mnt' static, avoiding need to tell kmemleak to mark it gray, as
suggested by Al Viro.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
---
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 69a5b6f..de3913b 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -521,7 +521,7 @@ static struct super_block *blockdev_superblock __read_mostly;
void __init bdev_cache_init(void)
{
int err;
- struct vfsmount *bd_mnt;
+ static struct vfsmount *bd_mnt;
bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
@@ -533,12 +533,7 @@ void __init bdev_cache_init(void)
bd_mnt = kern_mount(&bd_type);
if (IS_ERR(bd_mnt))
panic("Cannot create bdev pseudo-fs");
- /*
- * This vfsmount structure is only used to obtain the
- * blockdev_superblock, so tell kmemleak not to report it.
- */
- kmemleak_not_leak(bd_mnt);
- blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
+ blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
}
/*
--
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