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ubifs: dbg_check_idx_size: Fix kmemleak if loading znode failed

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If function dbg_check_idx_size() failed by loading znode in mounting
process, there are two problems:
  1. Allocated znodes won't be freed, which causes kmemleak in kernel:
     ubifs_mount
      dbg_check_idx_size
       dbg_walk_index
        c->zroot.znode = ubifs_load_znode
	child = ubifs_load_znode // failed
	// Loaded znodes won't be freed in error handling path.
  2. Global variable ubifs_clean_zn_cnt is not decreased, because
     ubifs_tnc_close() is not invoked in error handling path, which
     triggers a warning in ubifs_exit():
      WARNING: CPU: 1 PID: 1576 at fs/ubifs/super.c:2486 ubifs_exit
      Modules linked in: zstd ubifs(-) ubi nandsim
      CPU: 1 PID: 1576 Comm: rmmod Not tainted 6.7.0-rc6
      Call Trace:
	ubifs_exit+0xca/0xc70 [ubifs]
	__do_sys_delete_module+0x29a/0x4a0
	do_syscall_64+0x6f/0x140

Fix it by adding error handling path in dbg_check_idx_size() to release
tnc tree.

Fixes: 1e51764a3c ("UBIFS: add new flash file system")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Suggested-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Zhihao Cheng 2024-01-08 10:41:04 +08:00 committed by Richard Weinberger
parent 9277b3a649
commit 31a9d5f329
4 changed files with 31 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
fs/ubifs/debug.c
View File

@ -1742,17 +1742,22 @@ int dbg_check_idx_size(struct ubifs_info *c, long long idx_size)
err = dbg_walk_index(c, NULL, add_size, &calc);
if (err) {
ubifs_err(c, "error %d while walking the index", err);
return err;
goto out_err;
}
if (calc != idx_size) {
ubifs_err(c, "index size check failed: calculated size is %lld, should be %lld",
calc, idx_size);
dump_stack();
return -EINVAL;
err = -EINVAL;
goto out_err;
}
return 0;
out_err:
ubifs_destroy_tnc_tree(c);
return err;
}
/**

9
fs/ubifs/tnc.c
View File

@ -3116,14 +3116,7 @@ static void tnc_destroy_cnext(struct ubifs_info *c)
void ubifs_tnc_close(struct ubifs_info *c)
{
tnc_destroy_cnext(c);
if (c->zroot.znode) {
long n, freed;
n = atomic_long_read(&c->clean_zn_cnt);
freed = ubifs_destroy_tnc_subtree(c, c->zroot.znode);
ubifs_assert(c, freed == n);
atomic_long_sub(n, &ubifs_clean_zn_cnt);
}
ubifs_destroy_tnc_tree(c);
kfree(c->gap_lebs);
kfree(c->ilebs);
destroy_old_idx(c);

22
fs/ubifs/tnc_misc.c
View File

@ -250,6 +250,28 @@ long ubifs_destroy_tnc_subtree(const struct ubifs_info *c,
}
}
/**
* ubifs_destroy_tnc_tree - destroy all znodes connected to the TNC tree.
* @c: UBIFS file-system description object
*
* This function destroys the whole TNC tree and updates clean global znode
* count.
*/
void ubifs_destroy_tnc_tree(struct ubifs_info *c)
{
long n, freed;
if (!c->zroot.znode)
return;
n = atomic_long_read(&c->clean_zn_cnt);
freed = ubifs_destroy_tnc_subtree(c, c->zroot.znode);
ubifs_assert(c, freed == n);
atomic_long_sub(n, &ubifs_clean_zn_cnt);
c->zroot.znode = NULL;
}
/**
* read_znode - read an indexing node from flash and fill znode.
* @c: UBIFS file-system description object

1
fs/ubifs/ubifs.h
View File

@ -1903,6 +1903,7 @@ struct ubifs_znode *ubifs_tnc_postorder_next(const struct ubifs_info *c,
struct ubifs_znode *znode);
long ubifs_destroy_tnc_subtree(const struct ubifs_info *c,
struct ubifs_znode *zr);
void ubifs_destroy_tnc_tree(struct ubifs_info *c);
struct ubifs_znode *ubifs_load_znode(struct ubifs_info *c,
struct ubifs_zbranch *zbr,
struct ubifs_znode *parent, int iip);