Olga Kornievskaia a204501e17 nfsd: prevent panic for nfsv4.0 closed files in nfs4_show_open
Prior to commit 3f29cc82a8 ("nfsd: split sc_status out of
sc_type") states_show() relied on sc_type field to be of valid
type before calling into a subfunction to show content of a
particular stateid. From that commit, we split the validity of
the stateid into sc_status and no longer changed sc_type to 0
while unhashing the stateid. This resulted in kernel oopsing
for nfsv4.0 opens that stay around and in nfs4_show_open()
would derefence sc_file which was NULL.

Instead, for closed open stateids forgo displaying information
that relies of having a valid sc_file.

To reproduce: mount the server with 4.0, read and close
a file and then on the server cat /proc/fs/nfsd/clients/2/states

[  513.590804] Call trace:
[  513.590925]  _raw_spin_lock+0xcc/0x160
[  513.591119]  nfs4_show_open+0x78/0x2c0 [nfsd]
[  513.591412]  states_show+0x44c/0x488 [nfsd]
[  513.591681]  seq_read_iter+0x5d8/0x760
[  513.591896]  seq_read+0x188/0x208
[  513.592075]  vfs_read+0x148/0x470
[  513.592241]  ksys_read+0xcc/0x178

Fixes: 3f29cc82a8 ("nfsd: split sc_status out of sc_type")
Signed-off-by: Olga Kornievskaia <okorniev@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-08-23 12:25:46 -04:00
2022-09-28 09:02:20 +02:00
2024-07-07 14:23:46 -07:00
2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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