Re: [PATCH] reiserfs: check kstrdup failure

From: Jan Kara
Date: Wed May 25 2016 - 11:43:18 EST


On Tue 24-05-16 22:51:27, Mikulas Patocka wrote:
> 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>

OK, makes sense. I've added the patch to my tree and will push it to Linus.
Thanks for the patch.

Honza
>
> ---
> 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:
> --
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--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR