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The srv_mutex is used during writeback so cifs should ensure that
allocations done when that mutex is held are done with GFP_NOFS, to
avoid having direct reclaim ending up waiting for the same mutex and
causing a deadlock. This is detected by lockdep with the splat below:
======================================================
WARNING: possible circular locking dependency detected
5.18.0 #70 Not tainted
------------------------------------------------------
kswapd0/49 is trying to acquire lock:
ffff8880195782e0 (&tcp_ses->srv_mutex){+.+.}-{3:3}, at: compound_send_recv
but task is already holding lock:
ffffffffa98e66c0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (fs_reclaim){+.+.}-{0:0}:
fs_reclaim_acquire
kmem_cache_alloc_trace
__request_module
crypto_alg_mod_lookup
crypto_alloc_tfm_node
crypto_alloc_shash
cifs_alloc_hash
smb311_crypto_shash_allocate
smb311_update_preauth_hash
compound_send_recv
cifs_send_recv
SMB2_negotiate
smb2_negotiate
cifs_negotiate_protocol
cifs_get_smb_ses
cifs_mount
cifs_smb3_do_mount
smb3_get_tree
vfs_get_tree
path_mount
__x64_sys_mount
do_syscall_64
entry_SYSCALL_64_after_hwframe
-> #0 (&tcp_ses->srv_mutex){+.+.}-{3:3}:
__lock_acquire
lock_acquire
__mutex_lock
mutex_lock_nested
compound_send_recv
cifs_send_recv
SMB2_write
smb2_sync_write
cifs_write
cifs_writepage_locked
cifs_writepage
shrink_page_list
shrink_lruvec
shrink_node
balance_pgdat
kswapd
kthread
ret_from_fork
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&tcp_ses->srv_mutex);
lock(fs_reclaim);
lock(&tcp_ses->srv_mutex);
*** DEADLOCK ***
1 lock held by kswapd0/49:
#0: ffffffffa98e66c0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat
stack backtrace:
CPU: 2 PID: 49 Comm: kswapd0 Not tainted 5.18.0 #70
Call Trace:
<TASK>
dump_stack_lvl
dump_stack
print_circular_bug.cold
check_noncircular
__lock_acquire
lock_acquire
__mutex_lock
mutex_lock_nested
compound_send_recv
cifs_send_recv
SMB2_write
smb2_sync_write
cifs_write
cifs_writepage_locked
cifs_writepage
shrink_page_list
shrink_lruvec
shrink_node
balance_pgdat
kswapd
kthread
ret_from_fork
</TASK>
Fix this by using the memalloc_nofs_save/restore APIs around the places
where the srv_mutex is held. Do this in a wrapper function for the
lock/unlock of the srv_mutex, and rename the srv_mutex to avoid missing
call sites in the conversion.
Note that there is another lockdep warning involving internal crypto
locks, which was masked by this problem and is visible after this fix,
see the discussion in this thread:
https://lore.kernel.org/all/20220523123755.GA13668@axis.com/
Link: https://lore.kernel.org/r/CANT5p=rqcYfYMVHirqvdnnca4Mo+JQSw5Qu12v=kPfpk5yhhmg@mail.gmail.com/
Reported-by: Shyam Prasad N <nspmangalore@gmail.com>
Suggested-by: Lars Persson <larper@axis.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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The cifs_demultiplexer_thread should only call cifs_reconnect.
If any other thread wants to trigger a reconnect, they can do
so by updating the server tcpStatus to CifsNeedReconnect.
The last patch attempted to use the same helper function for
both types of threads, but that causes other issues
with lock dependencies.
This patch creates a new helper for non-cifsd threads, that
will indicate to cifsd that the server needs reconnect.
Fixes: 2a05137a0575 ("cifs: mark sessions for reconnection in helper function")
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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cifs_mark_tcp_ses_conns_for_reconnect helper function is now
meant to be used by any of the threads to mark a channel
(or all the channels) for reconnect.
Replace all such manual changes to tcpStatus to use this
helper function, which takes care that the right channels,
smb sessions and tcons are marked for reconnect.
Also includes one line minor change
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Recent restructuring of cifs_reconnect introduced a helper func
named cifs_ses_mark_for_reconnect, which updates the state of tcp
session for all the channels of a session for reconnect.
However, this does not update the session state and chans_need_reconnect
bitmask. This change fixes that.
Also, cifs_mark_tcp_sess_for_reconnect should mark set the bitmask
for all channels when the whole session is marked for reconnect.
Fixed that here too.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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While checking/updating status for tcp ses, smb ses or tcon,
we take GlobalMid_Lock. This doesn't make any sense.
Replaced it with cifs_tcp_ses_lock.
Ideally, we should take a spin lock per struct.
But since tcp ses, smb ses and tcon objects won't add up to a lot,
I think there should not be too much contention.
Also, in few other places, these are checked without locking.
Added locking for these.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Use new cifs_ses_mark_for_reconnect() helper to mark all session
channels for reconnect instead of duplicating it in different places.
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
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for SMB1.
This removes the dependency to DES.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Although in practice this can not occur (since IPv4 and IPv6 are the
only two cases currently supported), it is cleaner to avoid uninitialized
variable warnings.
Addresses smatch warning:
fs/cifs/cifs_swn.c:468 cifs_swn_store_swn_addr() error: uninitialized symbol 'port'.
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
CC: Samuel Cabrero <scabrero@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
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A typo is found out by codespell tool in 251th lines of cifs_swn.c:
$ codespell ./fs/cifs/
./cifs_swn.c:251: funciton ==> function
Fix a typo found by codespell.
Signed-off-by: Liu xuzhi <liu.xuzhi@zte.com.cn>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Fix inconsistent IS_ERR and PTR_ERR in cifs_find_swn_reg(). The proper
pointer to be passed as argument to PTR_ERR() is share_name.
This bug was detected with the help of Coccinelle.
Fixes: bf80e5d4259a ("cifs: Send witness register and unregister commands to userspace daemon")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Samuel Cabrero <scabrero@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
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This code is slightly nicer if we flip the cifs_sockaddr_equal()
around and pull all the code in one tab.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Samuel Cabrero <scabrero@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
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There are three error paths which need to unlock before returning.
Fixes: 121d947d4fe1 ("cifs: Handle witness client move notification")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Samuel Cabrero <scabrero@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
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The unlock is done in the caller, this is a stray which leads to a
double unlock bug.
Fixes: bf80e5d4259a ("cifs: Send witness register and unregister commands to userspace daemon")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Samuel Cabrero <scabrero@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Pull cifs updates from Steve French:
"The largest part are for support of the newer mount API which has been
needed for cifs/smb3 mounts for a long time due to the new API's
better handling of remount, and better error reporting. There are
three additional small cleanup patches for this being tested, that are
not included yet.
This series also includes addition of support for the SMB3 witness
protocol which can provide important notifications from the server to
client on server address or export or network changes. This can be
useful for example in order to be notified before the failure - when a
server's IP address changes (in the future it will allow us to support
server notifications of when a share is moved).
It also includes three patches for stable e.g. some that better handle
some confusing error messages during session establishment"
* tag '5.11-rc-smb3' of git://git.samba.org/sfrench/cifs-2.6: (55 commits)
cifs: update internal module version number
cifs: Fix support for remount when not changing rsize/wsize
cifs: handle "guest" mount parameter
cifs: correct four aliased mount parms to allow use of previous names
cifs: Tracepoints and logs for tracing credit changes.
cifs: fix use after free in cifs_smb3_do_mount()
cifs: fix rsize/wsize to be negotiated values
cifs: Fix some error pointers handling detected by static checker
smb3: remind users that witness protocol is experimental
cifs: update super_operations to show_devname
cifs: fix uninitialized variable in smb3_fs_context_parse_param
cifs: update mnt_cifs_flags during reconfigure
cifs: move update of flags into a separate function
cifs: remove ctx argument from cifs_setup_cifs_sb
cifs: do not allow changing posix_paths during remount
cifs: uncomplicate printing the iocharset parameter
cifs: don't create a temp nls in cifs_setup_ipc
cifs: simplify handling of cifs_sb/ctx->local_nls
cifs: we do not allow changing username/password/unc/... during remount
cifs: add initial reconfigure support
...
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* extract_hostname() and extract_sharename() never return NULL, so
use IS_ERR() instead of IS_ERR_OR_NULL() in cifs_find_swn_reg(). If
any of these functions return an error, then return an error pointer
instead of NULL.
* Change cifs_find_swn_reg() function to always return a valid pointer
or an error pointer, instead of returning NULL if the registration
is not found.
* Finally update cifs_find_swn_reg() callers to check for -EEXIST
instead of NULL.
* In cifs_get_swn_reg() the swnreg idr mutex was not unlocked in the
error path of cifs_find_swn_reg() call.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Samuel Cabrero <scabrero@suse.de>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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This message is sent to tell a client to close its current connection
and connect to the specified address.
Signed-off-by: Samuel Cabrero <scabrero@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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If the daemon starts after mounting a share, or if it crashes, this
provides a mechanism to register again.
Signed-off-by: Samuel Cabrero <scabrero@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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+ Indicate if witness feature is supported
+ Indicate if witness is used when dumping tcons
+ Dumps witness registrations. Example:
Witness registrations:
Id: 1 Refs: 1 Network name: 'fs.fover.ad'(y) Share name: 'share1'(y) \
Ip address: 192.168.103.200(n)
Signed-off-by: Samuel Cabrero <scabrero@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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+ Set a handler for the witness notification messages received from the
userspace daemon.
+ Handle the resource state change notification. When the resource
becomes unavailable or available set the tcp status to
CifsNeedReconnect for all channels.
Signed-off-by: Samuel Cabrero <scabrero@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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+ Define the generic netlink family commands and message attributes to
communicate with the userspace daemon
+ The register and unregister commands are sent when connecting or
disconnecting a tree. The witness registration keeps a pointer to
the tcon and has the same lifetime.
+ Each registration has an id allocated by an IDR. This id is sent to the
userspace daemon in the register command, and will be included in the
notification messages from the userspace daemon to retrieve from the
IDR the matching registration.
+ The authentication information is bundled in the register message.
If kerberos is used the message just carries a flag.
Signed-off-by: Samuel Cabrero <scabrero@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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