Description: NFS client crash due to index buffer overflow during Direct IO write causing kernel panic
References:
 https://bugzilla.redhat.com/show_bug.cgi?id=1835127
 https://bugzilla.redhat.com/show_bug.cgi?id=1824270
 https://bugzilla.suse.com/show_bug.cgi?id=1171984
Notes:
 carnil> Needs to be checked if this specific to Red Hat or an upstream
 carnil> issue.
 carnil> Maybe related to 18aad3d552c7 ("NFSv4.1 Refactor
 carnil> nfs4_init_session and nfs4_init_channel_attrs") [3.11-rc1] and
 carnil> 68bf05efb7fa ("nfs41: fix session fore channel negotiation")
 carnil> [2.6.33-rc1]?
 carnil> Further analysis seem to show that the issue is introduced in
 carnil> 1763da1234cb ("NFS: rewrite directio write to use async
 carnil> coalesce code") and fixed with 91f79c43d1b5 ("new helper:
 carnil> iov_iter_get_pages_alloc()").
Bugs:
upstream: released (3.16-rc1) [91f79c43d1b54d7154b118860d81b39bad07dfff]
4.19-upstream-stable: N/A "Fixed before branching point"
4.9-upstream-stable: N/A "Fixed before branching point"
3.16-upstream-stable: N/A "Fixed before branching point"
sid: released (3.16.2-2)
4.19-buster-security: N/A "Fixed before branching point"
4.9-stretch-security: N/A "Fixed before branching point"
3.16-jessie-security: N/A "Fixed before branching point"