b4c07bce79
I was seeing a null pointer deref in fs/super.c:vfs_kern_mount(). Some file system get_sb() handler was returning NULL mnt_sb with a non-negative return value. I also noticed a "hugetlbfs: Bad mount option:" message in the log. Turns out that hugetlbfs_parse_options() was not checking for an empty option string after call to strsep(). On failure, hugetlbfs_parse_options() returns 1. hugetlbfs_fill_super() just passed this return code back up the call stack where vfs_kern_mount() missed the error and proceeded with a NULL mnt_sb. Apparently introduced by patch: hugetlbfs-use-lib-parser-fix-docs.patch The problem was exposed by this line in my fstab: none /huge hugetlbfs defaults 0 0 It can also be demonstrated by invoking mount of hugetlbfs directly with no options or a bogus option. This patch: 1) adds the check for empty option to hugetlbfs_parse_options(), 2) enhances the error message to bracket any unrecognized option with quotes , 3) modifies hugetlbfs_parse_options() to return -EINVAL on any unrecognized option, 4) adds a BUG_ON() to vfs_kern_mount() to catch any get_sb() handler that returns a NULL mnt->mnt_sb with a return value >= 0. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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