Commit 01d6e087 authored May 24, 2016 by Mikulas Patocka Committed by Linus Torvalds May 28, 2016

affs: fix remount failure when there are no options changed



Commit c8f33d0b ("affs: kstrdup() memory handling") checks if the
kstrdup function returns NULL due to out-of-memory condition.

However, if we are remounting a filesystem with no change to
filesystem-specific options, the parameter data is NULL.  In this case,
kstrdup returns NULL (because it was passed NULL parameter), although no
out of memory condition exists.  The mount syscall then fails with
ENOMEM.

This patch fixes the bug.  We fail with ENOMEM only if data is non-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).

Fixes: c8f33d0b ("affs: kstrdup() memory handling")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org	# v4.1+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 44d51706

fs/affs/super.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -528,7 +528,7 @@ affs_remount(struct super_block sb, int flags, char *data)
		char *prefix = NULL;

		new_opts = kstrdup(data, GFP_KERNEL);
		if (!new_opts)
		if (data && !new_opts)
		return -ENOMEM;

		pr_debug("%s(flags=0x%x,opts=\"%s\")\n", __func__, *flags, data);
		@@ -546,6 +546,7 @@ affs_remount(struct super_block sb, int flags, char *data)
		}

		flush_delayed_work(&sbi->sb_work);
		if (new_opts)
		replace_mount_options(sb, new_opts);

		sbi->s_flags = mount_flags;

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