diff options
author | J. Bruce Fields <bfields@redhat.com> | 2019-04-12 16:37:30 -0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-06-22 08:18:20 +0200 |
commit | 198a54f07f51d4f52503ae611e0b0c1e8e445cef (patch) | |
tree | 2899ee2b4c36b255dfd0e8af841c7529df115d23 /kernel/debug | |
parent | e6779b264d69141da1645f9ec3b40fe1bde84ec2 (diff) |
nfsd: allow fh_want_write to be called twice
[ Upstream commit 0b8f62625dc309651d0efcb6a6247c933acd8b45 ]
A fuzzer recently triggered lockdep warnings about potential sb_writers
deadlocks caused by fh_want_write().
Looks like we aren't careful to pair each fh_want_write() with an
fh_drop_write().
It's not normally a problem since fh_put() will call fh_drop_write() for
us. And was OK for NFSv3 where we'd do one operation that might call
fh_want_write(), and then put the filehandle.
But an NFSv4 protocol fuzzer can do weird things like call unlink twice
in a compound, and then we get into trouble.
I'm a little worried about this approach of just leaving everything to
fh_put(). But I think there are probably a lot of
fh_want_write()/fh_drop_write() imbalances so for now I think we need it
to be more forgiving.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel/debug')
0 files changed, 0 insertions, 0 deletions