kernel/linux.git/fs/dlm/lock.c, branch v6.6.134

dlm: fix possible lkb_resource null dereference

2024-12-14T19:00:02+00:00

[ Upstream commit b98333c67daf887c724cd692e88e2db9418c0861 ] This patch fixes a possible null pointer dereference when this function is called from request_lock() as lkb->lkb_resource is not assigned yet, only after validate_lock_args() by calling attach_lkb(). Another issue is that a resource name could be a non printable bytearray and we cannot assume to be ASCII coded. The log functionality is probably never being hit when DLM is used in normal way and no debug logging is enabled. The null pointer dereference can only occur on a new created lkb that does not have the resource assigned yet, it probably never hits the null pointer dereference but we should be sure that other changes might not change this behaviour and we actually can hit the mentioned null pointer dereference. In this patch we just drop the printout of the resource name, the lkb id is enough to make a possible connection to a resource name if this exists. Signed-off-by: Alexander Aring Signed-off-by: David Teigland Signed-off-by: Sasha Levin

fs: dlm: constify receive buffer

2023-08-10T15:33:03+00:00

The dlm receive buffer should be never manipulated as DLM is the last instance of parsing layer. This patch constify the whole receive buffer so we are sure it never gets manipulated when it's being parsed. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: drop rxbuf manipulation in dlm_recover_master_copy

2023-08-10T15:33:03+00:00

Currently dlm_recover_master_copy() manipulates the receive buffer of an rcom lock message and modifies it on the fly so a later memcpy() to a new rcom message with the same message has those new values. This patch avoids manipulating the received rcom message by store the values for the new rcom message in paremter assigned with call by reference. Later when dlm_send_rcom_lock() constructs a new message and memcpy() the receive buffer those values will be set on the new constructed message. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: get recovery sequence number as parameter

2023-08-10T15:33:03+00:00

This patch removes a read of the ls->ls_recover_seq uint64_t number in _create_rcom(). If the ls->ls_recover_seq is readed the ls_recover_lock need to held. However this number was always readed before when any rcom message is received and it's not necessary to read it again from a per lockspace variable to use it for the replying message. This patch will pass the sequence number as parameter so another read of ls->ls_recover_seq and holding the ls->ls_recover_lock is not required. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: handle lkb wait count as atomic_t

2023-06-14T15:17:33+00:00

Currently the lkb_wait_count is locked by the rsb lock and it should be fine to handle lkb_wait_count as non atomic_t value. However for the overall process of reducing locking this patch converts it to an atomic_t value. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: warn about messages from left nodes

2023-06-14T15:17:33+00:00

This patch warns about messages which are received from nodes who already left the lockspace resource signaled by the cluster manager. Before commit 489d8e559c65 ("fs: dlm: add reliable connection if reconnect") there was a synchronization issue with the socket lifetime and the cluster event of leaving a lockspace and other nodes did not stop of sending messages because the cluster manager has a pending message to leave the lockspace. The reliable session layer for dlm use sequence numbers to ensure dlm message were never being dropped. If this is not corrected synchronized we have a problem, this patch will use the filter case and turn it into a WARN_ON_ONCE() so we seeing such issue on the kernel log because it should never happen now. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: stop unnecessarily filling zero ms_extra bytes

2023-04-21T16:46:47+00:00

Commit 7175e131ebba ("fs: dlm: fix invalid derefence of sb_lvbptr") fixes an issue when the lkb->lkb_lvbptr set to an dangled pointer and an followed memcpy() would fail. It was fixed by an additional check of DLM_LKF_VALBLK flag. The mentioned commit forgot to add an additional check if DLM_LKF_VALBLK is set for the additional amount of LVB data allocated in a dlm message. This patch is changing the message allocation to check additionally if DLM_LKF_VALBLK is set otherwise a dangled lkb->lkb_lvbptr pointer would allocated zero LVB message data which not gets filled with actual data. This patch is however only a cleanup to reduce the amount of zero bytes transmitted over network as receive_lvb() will only evaluates message LVB data if DLM_LKF_VALBLK is set. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: switch lkb_sbflags to atomic ops

2023-03-06T21:49:07+00:00

This patch moves lkb_sbflags handling to atomic bits ops. This should prepare for a possible manipulating of lkb_sbflags flags at the same time by concurrent execution. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: rsb hash table flag value to atomic ops

2023-03-06T21:49:07+00:00

This patch moves the rsb hash table handling to atomic flag operations. The flag operations for DLM_RTF_SHRINK are protected by ls->ls_rsbtbl[b].lock. However we switch to atomic ops if new possible flags will be used in a different way and don't assume such lock dependencies. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: move internal flags to atomic ops

2023-03-06T21:49:07+00:00

This patch will move the lkb_flags value to the recently introduced lkb_iflags value. For lkb_iflags we use atomic bit operations because some flags like DLM_IFL_CB_PENDING are used while non rsb lock is held to avoid issues with other flag manipulations which might run at the same time we switch to atomic bit operations. Snapshot the bit values to an uint32_t value is only used for debugging/logging use cases and don't need to be 100% correct. Signed-off-by: Alexander Aring Signed-off-by: David Teigland