[PATCH] reiserfs: check kstrdup failure

From: Mikulas Patocka
Date: Tue May 24 2016 - 17:15:16 EST


Check out-of-memory failure of the kstrdup option. Note that the argument
"arg" may be NULL (in that case kstrup returns NULL), so out of memory
condition happened if arg was non-NULL and kstrdup returned NULL.

The patch also changes the call to replace_mount_options - if we didn't
pass any filesystem-specific options, we don't call replace_mount_options
(thus we don't erase existing reported options).

Note that to properly report options after remount, the reiserfs
filesystem should implement the show_options method. Without the
show_options method, options changed with remount replace existing
options.

Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>

---
fs/reiserfs/super.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

Index: linux-4.6/fs/reiserfs/super.c
===================================================================
--- linux-4.6.orig/fs/reiserfs/super.c 2016-05-19 20:59:46.000000000 +0200
+++ linux-4.6/fs/reiserfs/super.c 2016-05-19 21:00:00.000000000 +0200
@@ -1393,7 +1393,7 @@ static int reiserfs_remount(struct super
unsigned long safe_mask = 0;
unsigned int commit_max_age = (unsigned int)-1;
struct reiserfs_journal *journal = SB_JOURNAL(s);
- char *new_opts = kstrdup(arg, GFP_KERNEL);
+ char *new_opts;
int err;
char *qf_names[REISERFS_MAXQUOTAS];
unsigned int qfmt = 0;
@@ -1401,6 +1401,10 @@ static int reiserfs_remount(struct super
int i;
#endif

+ new_opts = kstrdup(arg, GFP_KERNEL);
+ if (arg && !new_opts)
+ return -ENOMEM;
+
sync_filesystem(s);
reiserfs_write_lock(s);

@@ -1546,7 +1550,8 @@ static int reiserfs_remount(struct super
}

out_ok_unlocked:
- replace_mount_options(s, new_opts);
+ if (new_opts)
+ replace_mount_options(s, new_opts);
return 0;

out_err_unlock: