tjh.dev
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.
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1442907
3
927
Clone this repository
https://tangled.org/tjh.dev/kernel
https://tangled.org/did:plc:65gha4t3avpfpzmvpbwovss7/kernel
git@gordian.tjh.dev:tjh.dev/kernel
git@gordian.tjh.dev:did:plc:65gha4t3avpfpzmvpbwovss7/kernel
For self-hosted knots, clone URLs may differ based on your setup.
Download tar.gz
The lock ordering rules listed as comments in cifsglob.h were
missing some lock details and also the fid_lock.
Updated those notes in this commit.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
When calling cifs_reconnect, before the connection to the
server is reestablished, the code today does a DNS resolution and
updates server->dstaddr.
However, this is not necessary for secondary channels. Secondary
channels use the interface list returned by the server to decide
which address to connect to. And that happens after tcon is reconnected
and server interfaces are requested.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
When the server interface info changes (more common in clustered
servers like Azure Files), the per-channel iface gets updated.
However, this did not update the corresponding dstaddr. As a result
these channels will still connect (or try connecting) to older addresses.
Fixes: b54034a73baf ("cifs: during reconnect, update interface if necessary")
Cc: <stable@vger.kernel.org>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
cifs_reconnect can be called with a flag to mark the session as needing
reconnect too. When this is done, we expect the connections of all
channels to be reconnected too, which is not happening today.
Without doing this, we have seen bad things happen when primary and
secondary channels are connected to different servers (in case of cloud
services like Azure Files SMB).
This change would force all connections to reconnect as well, not just
the sessions and tcons.
Cc: <stable@vger.kernel.org>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Implement ParentLeaseKey logic in cifs_do_create() by looking up the
parent cfid, copying its lease key into the fid struct, and setting
the appropriate lease flag.
Fixes: f047390a097e ("CIFS: Add create lease v2 context for SMB3")
Signed-off-by: Henrique Carvalho <henrique.carvalho@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Implement ParentLeaseKey logic in open_cached_dir() by looking up the
parent cfid, copying its lease key into the fid struct, and setting
the appropriate lease flag.
Fixes: f047390a097e ("CIFS: Add create lease v2 context for SMB3")
Signed-off-by: Henrique Carvalho <henrique.carvalho@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
According to MS-SMB2 3.2.4.3.8, when opening a file the client must
lookup its parent directory, copy that entry’s LeaseKey into
ParentLeaseKey, and set SMB2_LEASE_FLAG_PARENT_LEASE_KEY_SET.
Extend lease context functions to carry a parent_lease_key and
lease_flags and to add them to the lease context buffer accordingly in
smb3_create_lease_buf. Also add a parent_lease_key field to struct
cifs_fid and lease_flags to cifs_open_parms.
Only applies to the SMB 3.x dialect family.
Fixes: f047390a097e ("CIFS: Add create lease v2 context for SMB3")
Signed-off-by: Henrique Carvalho <henrique.carvalho@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
For TRANS2 QUERY_PATH_INFO request when the path does not exist, the
Windows NT SMB server returns error response STATUS_OBJECT_NAME_NOT_FOUND
or ERRDOS/ERRbadfile without the SMBFLG_RESPONSE flag set. Similarly it
returns STATUS_DELETE_PENDING when the file is being deleted. And looks
like that any error response from TRANS2 QUERY_PATH_INFO does not have
SMBFLG_RESPONSE flag set.
So relax check in check_smb_hdr() for detecting if the packet is response
for this special case.
This change fixes stat() operation against Windows NT SMB servers and also
all operations which depends on -ENOENT result from stat like creat() or
mkdir().
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Validate the SMB1 query reparse point response per [MS-CIFS] section
2.2.7.2 NT_TRANSACT_IOCTL.
NT_TRANSACT_IOCTL response contains one word long setup data after which is
ByteCount member. So check that SetupCount is 1 before trying to read and
use ByteCount member.
Output setup data contains ReturnedDataLen member which is the output
length of executed IOCTL command by remote system. So check that output was
not truncated before transferring over network.
Change MaxSetupCount of NT_TRANSACT_IOCTL request from 4 to 1 as io_rsp
structure already expects one word long output setup data. This should
prevent server sending incompatible structure (in case it would be extended
in future, which is unlikely).
Change MaxParameterCount of NT_TRANSACT_IOCTL request from 2 to 0 as
NT IOCTL does not have any documented output parameters and this function
does not parse any output parameters at all.
Fixes: ed3e0a149b58 ("smb: client: implement ->query_reparse_point() for SMB1")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
[MS-CIFS] specification in section 2.2.4.53.1 where is described
SMB_COM_SESSION_SETUP_ANDX Request, for SessionKey field says:
The client MUST set this field to be equal to the SessionKey field in
the SMB_COM_NEGOTIATE Response for this SMB connection.
Linux SMB client currently set this field to zero. This is working fine
against Windows NT SMB servers thanks to [MS-CIFS] product behavior <94>:
Windows NT Server ignores the client's SessionKey.
For compatibility with [MS-CIFS], set this SessionKey field in Session
Setup Request to value retrieved from Negotiate response.
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
SMB1 Session Setup NTLMSSP Request in non-UNICODE mode is similar to
UNICODE mode, just strings are encoded in ASCII and not in UTF-16.
With this change it is possible to setup SMB1 session with NTLM
authentication in non-UNICODE mode with Windows SMB server.
This change fixes mounting SMB1 servers with -o nounicode mount option
together with -o sec=ntlmssp mount option (which is the default sec=).
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
page is checked for null in __build_path_from_dentry_optional_prefix
when tcon->origin_fullpath is not set. However, the check is missing when
it is set.
Add a check to prevent a potential NULL pointer dereference.
Signed-off-by: Ruben Devos <devosruben6@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
SMB2_QFS_info() has been unused since 2018's
commit 730928c8f4be ("cifs: update smb2_queryfs() to use compounding")
sign_CIFS_PDUs has been unused since 2009's
commit 2edd6c5b0517 ("[CIFS] NTLMSSP support moving into new file, old dead
code removed")
Remove them.
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
This is kind of last-minute, but Al Viro reported that the new
FOP_DONTCACHE flag causes memory corruption due to use-after-free
issues.
This was triggered by commit 974c5e6139db ("xfs: flag as supporting
FOP_DONTCACHE"), but that is not the underlying bug - it is just the
first user of the flag.
Vlastimil Babka suspects the underlying problem stems from the
folio_end_writeback() logic introduced in commit fb7d3bc414939
("mm/filemap: drop streaming/uncached pages when writeback completes").
The most straightforward fix would be to just revert the commit that
exposed this, but Matthew Wilcox points out that other filesystems are
also starting to enable the FOP_DONTCACHE logic, so this instead
disables that bit globally for now.
The fix will hopefully end up being trivial and we can just re-enable
this logic after more testing, but until such a time we'll have to
disable the new FOP_DONTCACHE flag.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/all/20250525083209.GS2023217@ZenIV/
Triggered-by: 974c5e6139db ("xfs: flag as supporting FOP_DONTCACHE")
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull hotfixes from Andrew Morton:
"22 hotfixes.
13 are cc:stable and the remainder address post-6.14 issues or aren't
considered necessary for -stable kernels. 19 are for MM"
* tag 'mm-hotfixes-stable-2025-05-25-00-58' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (22 commits)
mailmap: add Jarkko's employer email address
mm: fix copy_vma() error handling for hugetlb mappings
memcg: always call cond_resched() after fn()
mm/hugetlb: fix kernel NULL pointer dereference when replacing free hugetlb folios
mm: vmalloc: only zero-init on vrealloc shrink
mm: vmalloc: actually use the in-place vrealloc region
alloc_tag: allocate percpu counters for module tags dynamically
module: release codetag section when module load fails
mm/cma: make detection of highmem_start more robust
MAINTAINERS: add mm memory policy section
MAINTAINERS: add mm ksm section
kasan: avoid sleepable page allocation from atomic context
highmem: add folio_test_partial_kmap()
MAINTAINERS: add hung-task detector section
taskstats: fix struct taskstats breaks backward compatibility since version 15
mm/truncate: fix out-of-bounds when doing a right-aligned split
MAINTAINERS: add mm reclaim section
MAINTAINERS: update page allocator section
mm: fix VM_UFFD_MINOR == VM_SHADOW_STACK on USERFAULTFD=y && ARM64_GCS=y
mm: mmap: map MAP_STACK to VM_NOHUGEPAGE only if THP is enabled
...
README