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To:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Hugh Dickins <hughd@google.com>
Cc:     Linux-MM <linux-mm@kvack.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        David Howells <dhowells@redhat.com>
From:   Laura Abbott <labbott@redhat.com>
Subject: mount on tmpfs failing to parse context option
Message-ID: <d5b67332-57b7-c19a-0462-f84d07ef1a16@redhat.com>
Date:   Mon, 30 Sep 2019 12:07:18 -0400
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Hi,

Fedora got a bug report https://bugzilla.redhat.com/show_bug.cgi?id=1757104
of a failure to parse options with the context mount option. From the reporter:


$ unshare -rm mount -t tmpfs tmpfs /tmp -o 'context="system_u:object_r:container_file_t:s0:c475,c690"'
mount: /tmp: wrong fs type, bad option, bad superblock on tmpfs, missing codepage or helper program, or other error.


Sep 30 16:50:42 kernel: tmpfs: Unknown parameter 'c690"'

I haven't asked the reporter to bisect yet but I'm suspecting one of the
conversion to the new mount API:

$ git log --oneline v5.3..origin/master mm/shmem.c
edf445ad7c8d Merge branch 'hugepage-fallbacks' (hugepatch patches from David Rientjes)
19deb7695e07 Revert "Revert "Revert "mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask""
28eb3c808719 shmem: fix obsolete comment in shmem_getpage_gfp()
4101196b19d7 mm: page cache: store only head pages in i_pages
d8c6546b1aea mm: introduce compound_nr()
f32356261d44 vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API
626c3920aeb4 shmem_parse_one(): switch to use of fs_parse()
e04dc423ae2c shmem_parse_options(): take handling a single option into a helper
f6490b7fbb82 shmem_parse_options(): don't bother with mpol in separate variable
0b5071dd323d shmem_parse_options(): use a separate structure to keep the results
7e30d2a5eb0b make shmem_fill_super() static


I didn't find another report or a fix yet. Is it worth asking the reporter to bisect?

Thanks,
Laura