kernel/linux.git/fs/dlm, branch v5.15.209

dlm: fix possible lkb_resource null dereference

2026-06-01T15:35:10+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 [ The context change is due to the commit 9ac8ba46a701 ("fs: dlm: handle -EINVAL as log_error()") in v6.1 which is irrelevant to the logic of this patch. ] Signed-off-by: Johnny Hao Signed-off-by: Greg Kroah-Hartman

fs: dlm: fix use after free in midcomms commit

2026-06-01T15:35:09+00:00

[ Upstream commit 724b6bab0d75f1dc01fdfbf7fe8d4217a5cb90ba ] While working on processing dlm message in softirq context I experienced the following KASAN use-after-free warning: [ 151.760477] ================================================================== [ 151.761803] BUG: KASAN: use-after-free in dlm_midcomms_commit_mhandle+0x19d/0x4b0 [ 151.763414] Read of size 4 at addr ffff88811a980c60 by task lock_torture/1347 [ 151.765284] CPU: 7 PID: 1347 Comm: lock_torture Not tainted 6.1.0-rc4+ #2828 [ 151.766778] Hardware name: Red Hat KVM/RHEL-AV, BIOS 1.16.0-3.module+el8.7.0+16134+e5908aa2 04/01/2014 [ 151.768726] Call Trace: [ 151.769277] [ 151.769748] dump_stack_lvl+0x5b/0x86 [ 151.770556] print_report+0x180/0x4c8 [ 151.771378] ? kasan_complete_mode_report_info+0x7c/0x1e0 [ 151.772241] ? dlm_midcomms_commit_mhandle+0x19d/0x4b0 [ 151.773069] kasan_report+0x93/0x1a0 [ 151.773668] ? dlm_midcomms_commit_mhandle+0x19d/0x4b0 [ 151.774514] __asan_load4+0x7e/0xa0 [ 151.775089] dlm_midcomms_commit_mhandle+0x19d/0x4b0 [ 151.775890] ? create_message.isra.29.constprop.64+0x57/0xc0 [ 151.776770] send_common+0x19f/0x1b0 [ 151.777342] ? remove_from_waiters+0x60/0x60 [ 151.778017] ? lock_downgrade+0x410/0x410 [ 151.778648] ? __this_cpu_preempt_check+0x13/0x20 [ 151.779421] ? rcu_lockdep_current_cpu_online+0x88/0xc0 [ 151.780292] _convert_lock+0x46/0x150 [ 151.780893] convert_lock+0x7b/0xc0 [ 151.781459] dlm_lock+0x3ac/0x580 [ 151.781993] ? 0xffffffffc0540000 [ 151.782522] ? torture_stop+0x120/0x120 [dlm_locktorture] [ 151.783379] ? dlm_scan_rsbs+0xa70/0xa70 [ 151.784003] ? preempt_count_sub+0xd6/0x130 [ 151.784661] ? is_module_address+0x47/0x70 [ 151.785309] ? torture_stop+0x120/0x120 [dlm_locktorture] [ 151.786166] ? 0xffffffffc0540000 [ 151.786693] ? lockdep_init_map_type+0xc3/0x360 [ 151.787414] ? 0xffffffffc0540000 [ 151.787947] torture_dlm_lock_sync.isra.3+0xe9/0x150 [dlm_locktorture] [ 151.789004] ? torture_stop+0x120/0x120 [dlm_locktorture] [ 151.789858] ? 0xffffffffc0540000 [ 151.790392] ? lock_torture_cleanup+0x20/0x20 [dlm_locktorture] [ 151.791347] ? delay_tsc+0x94/0xc0 [ 151.791898] torture_ex_iter+0xc3/0xea [dlm_locktorture] [ 151.792735] ? torture_start+0x30/0x30 [dlm_locktorture] [ 151.793606] lock_torture+0x177/0x270 [dlm_locktorture] [ 151.794448] ? torture_dlm_lock_sync.isra.3+0x150/0x150 [dlm_locktorture] [ 151.795539] ? lock_torture_stats+0x80/0x80 [dlm_locktorture] [ 151.796476] ? do_raw_spin_lock+0x11e/0x1e0 [ 151.797152] ? mark_held_locks+0x34/0xb0 [ 151.797784] ? _raw_spin_unlock_irqrestore+0x30/0x70 [ 151.798581] ? __kthread_parkme+0x79/0x110 [ 151.799246] ? trace_preempt_on+0x2a/0xf0 [ 151.799902] ? __kthread_parkme+0x79/0x110 [ 151.800579] ? preempt_count_sub+0xd6/0x130 [ 151.801271] ? __kasan_check_read+0x11/0x20 [ 151.801963] ? __kthread_parkme+0xec/0x110 [ 151.802630] ? lock_torture_stats+0x80/0x80 [dlm_locktorture] [ 151.803569] kthread+0x192/0x1d0 [ 151.804104] ? kthread_complete_and_exit+0x30/0x30 [ 151.804881] ret_from_fork+0x1f/0x30 [ 151.805480] [ 151.806111] Allocated by task 1347: [ 151.806681] kasan_save_stack+0x26/0x50 [ 151.807308] kasan_set_track+0x25/0x30 [ 151.807920] kasan_save_alloc_info+0x1e/0x30 [ 151.808609] __kasan_slab_alloc+0x63/0x80 [ 151.809263] kmem_cache_alloc+0x1ad/0x830 [ 151.809916] dlm_allocate_mhandle+0x17/0x20 [ 151.810590] dlm_midcomms_get_mhandle+0x96/0x260 [ 151.811344] _create_message+0x95/0x180 [ 151.811994] create_message.isra.29.constprop.64+0x57/0xc0 [ 151.812880] send_common+0x129/0x1b0 [ 151.813467] _convert_lock+0x46/0x150 [ 151.814074] convert_lock+0x7b/0xc0 [ 151.814648] dlm_lock+0x3ac/0x580 [ 151.815199] torture_dlm_lock_sync.isra.3+0xe9/0x150 [dlm_locktorture] [ 151.816258] torture_ex_iter+0xc3/0xea [dlm_locktorture] [ 151.817129] lock_torture+0x177/0x270 [dlm_locktorture] [ 151.817986] kthread+0x192/0x1d0 [ 151.818518] ret_from_fork+0x1f/0x30 [ 151.819369] Freed by task 1336: [ 151.819890] kasan_save_stack+0x26/0x50 [ 151.820514] kasan_set_track+0x25/0x30 [ 151.821128] kasan_save_free_info+0x2e/0x50 [ 151.821812] __kasan_slab_free+0x107/0x1a0 [ 151.822483] kmem_cache_free+0x204/0x5e0 [ 151.823152] dlm_free_mhandle+0x18/0x20 [ 151.823781] dlm_mhandle_release+0x2e/0x40 [ 151.824454] rcu_core+0x583/0x1330 [ 151.825047] rcu_core_si+0xe/0x20 [ 151.825594] __do_softirq+0xf4/0x5c2 [ 151.826450] Last potentially related work creation: [ 151.827238] kasan_save_stack+0x26/0x50 [ 151.827870] __kasan_record_aux_stack+0xa2/0xc0 [ 151.828609] kasan_record_aux_stack_noalloc+0xb/0x20 [ 151.829415] call_rcu+0x4c/0x760 [ 151.829954] dlm_mhandle_delete+0x97/0xb0 [ 151.830718] dlm_process_incoming_buffer+0x2fc/0xb30 [ 151.831524] process_dlm_messages+0x16e/0x470 [ 151.832245] process_one_work+0x505/0xa10 [ 151.832905] worker_thread+0x67/0x650 [ 151.833507] kthread+0x192/0x1d0 [ 151.834046] ret_from_fork+0x1f/0x30 [ 151.834900] The buggy address belongs to the object at ffff88811a980c30 which belongs to the cache dlm_mhandle of size 88 [ 151.836894] The buggy address is located 48 bytes inside of 88-byte region [ffff88811a980c30, ffff88811a980c88) [ 151.839007] The buggy address belongs to the physical page: [ 151.839904] page:0000000076cf5d62 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11a980 [ 151.841378] flags: 0x8000000000000200(slab|zone=2) [ 151.842141] raw: 8000000000000200 0000000000000000 dead000000000122 ffff8881089b43c0 [ 151.843401] raw: 0000000000000000 0000000000220022 00000001ffffffff 0000000000000000 [ 151.844640] page dumped because: kasan: bad access detected [ 151.845822] Memory state around the buggy address: [ 151.846602] ffff88811a980b00: fb fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb [ 151.847761] ffff88811a980b80: fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb fb [ 151.848921] >ffff88811a980c00: fb fb fc fc fc fc fa fb fb fb fb fb fb fb fb fb [ 151.850076] ^ [ 151.851085] ffff88811a980c80: fb fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb [ 151.852269] ffff88811a980d00: fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb fc [ 151.853428] ================================================================== [ 151.855618] Disabling lock debugging due to kernel taint It is accessing a mhandle in dlm_midcomms_commit_mhandle() and the mhandle was freed by a call_rcu() call in dlm_process_incoming_buffer(), dlm_mhandle_delete(). It looks like it was freed because an ack of this message was received. There is a short race between committing the dlm message to be transmitted and getting an ack back. If the ack is faster than returning from dlm_midcomms_commit_msg_3_2(), then we run into a use-after free because we still need to reference the mhandle when calling srcu_read_unlock(). To avoid that, we don't allow that mhandle to be freed between dlm_midcomms_commit_msg_3_2() and srcu_read_unlock() by using rcu read lock. We can do that because mhandle is protected by rcu handling. Cc: stable@vger.kernel.org Fixes: 489d8e559c65 ("fs: dlm: add reliable connection if reconnect") Signed-off-by: Alexander Aring Signed-off-by: David Teigland [ Minor conflict resolved. ] Signed-off-by: Jianqiang kang Signed-off-by: Greg Kroah-Hartman

dlm: check for defined force value in dlm_lockspace_release

2025-10-29T13:03:10+00:00

[ Upstream commit 6af515c9f3ccec3eb8a262ca86bef2c499d07951 ] Force values over 3 are undefined, so don't treat them as 3. Signed-off-by: Alexander Aring Signed-off-by: David Teigland Signed-off-by: Sasha Levin

dlm: make tcp still work in multi-link env

2025-06-04T12:37:56+00:00

[ Upstream commit 03d2b62208a336a3bb984b9465ef6d89a046ea22 ] This patch bypasses multi-link errors in TCP mode, allowing dlm to operate on the first tcp link. Signed-off-by: Heming Zhao Signed-off-by: David Teigland Signed-off-by: Sasha Levin

dlm: fix plock lookup when using multiple lockspaces

2023-09-19T10:22:52+00:00

commit 7c53e847ff5e97f033fdd31f71949807633d506b upstream. All posix lock ops, for all lockspaces (gfs2 file systems) are sent to userspace (dlm_controld) through a single misc device. The dlm_controld daemon reads the ops from the misc device and sends them to other cluster nodes using separate, per-lockspace cluster api communication channels. The ops for a single lockspace are ordered at this level, so that the results are received in the same sequence that the requests were sent. When the results are sent back to the kernel via the misc device, they are again funneled through the single misc device for all lockspaces. When the dlm code in the kernel processes the results from the misc device, these results will be returned in the same sequence that the requests were sent, on a per-lockspace basis. A recent change in this request/reply matching code missed the "per-lockspace" check (fsid comparison) when matching request and reply, so replies could be incorrectly matched to requests from other lockspaces. Cc: stable@vger.kernel.org Reported-by: Barry Marson Fixes: 57e2c2f2d94c ("fs: dlm: fix mismatch of plock results from userspace") Signed-off-by: Alexander Aring Signed-off-by: David Teigland Signed-off-by: Greg Kroah-Hartman

fs: dlm: fix mismatch of plock results from userspace

2023-08-30T14:18:11+00:00

[ Upstream commit 57e2c2f2d94cfd551af91cedfa1af6d972487197 ] When a waiting plock request (F_SETLKW) is sent to userspace for processing (dlm_controld), the result is returned at a later time. That result could be incorrectly matched to a different waiting request in cases where the owner field is the same (e.g. different threads in a process.) This is fixed by comparing all the properties in the request and reply. The results for non-waiting plock requests are now matched based on list order because the results are returned in the same order they were sent. Cc: stable@vger.kernel.org Signed-off-by: Alexander Aring Signed-off-by: David Teigland Signed-off-by: Sasha Levin

fs: dlm: use dlm_plock_info for do_unlock_close

2023-08-30T14:18:11+00:00

[ Upstream commit 4d413ae9ced4180c0e2114553c3a7560b509b0f8 ] This patch refactors do_unlock_close() by using only struct dlm_plock_info as a parameter. Signed-off-by: Alexander Aring Signed-off-by: David Teigland Stable-dep-of: 57e2c2f2d94c ("fs: dlm: fix mismatch of plock results from userspace") Signed-off-by: Sasha Levin

fs: dlm: change plock interrupted message to debug again

2023-08-30T14:18:11+00:00

[ Upstream commit ea06d4cabf529eefbe7e89e3a8325f1f89355ccd ] This patch reverses the commit bcfad4265ced ("dlm: improve plock logging if interrupted") by moving it to debug level and notifying the user an op was removed. Signed-off-by: Alexander Aring Signed-off-by: David Teigland Stable-dep-of: 57e2c2f2d94c ("fs: dlm: fix mismatch of plock results from userspace") Signed-off-by: Sasha Levin

fs: dlm: add pid to debug log

2023-08-30T14:18:11+00:00

[ Upstream commit 19d7ca051d303622c423b4cb39e6bde5d177328b ] This patch adds the pid information which requested the lock operation to the debug log output. Signed-off-by: Alexander Aring Signed-off-by: David Teigland Stable-dep-of: 57e2c2f2d94c ("fs: dlm: fix mismatch of plock results from userspace") Signed-off-by: Sasha Levin

dlm: replace usage of found with dedicated list iterator variable

2023-08-30T14:18:11+00:00

[ Upstream commit dc1acd5c94699389a9ed023e94dd860c846ea1f6 ] To move the list iterator variable into the list_for_each_entry_*() macro in the future it should be avoided to use the list iterator variable after the loop body. To *never* use the list iterator variable after the loop it was concluded to use a separate iterator variable instead of a found boolean [1]. This removes the need to use a found variable and simply checking if the variable was set, can determine if the break/goto was hit. Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1] Signed-off-by: Jakob Koschel Signed-off-by: Alexander Aring Signed-off-by: David Teigland Stable-dep-of: 57e2c2f2d94c ("fs: dlm: fix mismatch of plock results from userspace") Signed-off-by: Sasha Levin