kernel/lib, branch linux-6.2.y

debugobject: Ensure pool refill (again)

2023-05-11T14:11:36Z

commit 0af462f19e635ad522f28981238334620881badc upstream. The recent fix to ensure atomicity of lookup and allocation inadvertently broke the pool refill mechanism. Prior to that change debug_objects_activate() and debug_objecs_assert_init() invoked debug_objecs_init() to set up the tracking object for statically initialized objects. That's not longer the case and debug_objecs_init() is now the only place which does pool refills. Depending on the number of statically initialized objects this can be enough to actually deplete the pool, which was observed by Ido via a debugobjects OOM warning. Restore the old behaviour by adding explicit refill opportunities to debug_objects_activate() and debug_objecs_assert_init(). Fixes: 63a759694eed ("debugobject: Prevent init race with static objects") Reported-by: Ido Schimmel Signed-off-by: Thomas Gleixner Tested-by: Ido Schimmel Link: https://lore.kernel.org/r/871qk05a9d.ffs@tglx Signed-off-by: Greg Kroah-Hartman

debugobject: Prevent init race with static objects

2023-05-11T14:11:07Z

[ Upstream commit 63a759694eed61025713b3e14dd827c8548daadc ] Statically initialized objects are usually not initialized via the init() function of the subsystem. They are special cased and the subsystem provides a function to validate whether an object which is not yet tracked by debugobjects is statically initialized. This means the object is started to be tracked on first use, e.g. activation. This works perfectly fine, unless there are two concurrent operations on that object. Schspa decoded the problem: T0 T1 debug_object_assert_init(addr) lock_hash_bucket() obj = lookup_object(addr); if (!obj) { unlock_hash_bucket(); - > preemption lock_subsytem_object(addr); activate_object(addr) lock_hash_bucket(); obj = lookup_object(addr); if (!obj) { unlock_hash_bucket(); if (is_static_object(addr)) init_and_track(addr); lock_hash_bucket(); obj = lookup_object(addr); obj->state = ACTIVATED; unlock_hash_bucket(); subsys function modifies content of addr, so static object detection does not longer work. unlock_subsytem_object(addr); if (is_static_object(addr)) <- Fails debugobject emits a warning and invokes the fixup function which reinitializes the already active object in the worst case. This race exists forever, but was never observed until mod_timer() got a debug_object_assert_init() added which is outside of the timer base lock held section right at the beginning of the function to cover the lockless early exit points too. Rework the code so that the lookup, the static object check and the tracking object association happens atomically under the hash bucket lock. This prevents the issue completely as all callers are serialized on the hash bucket lock and therefore cannot observe inconsistent state. Fixes: 3ac7fe5a4aab ("infrastructure to debug (dynamic) objects") Reported-by: syzbot+5093ba19745994288b53@syzkaller.appspotmail.com Debugged-by: Schspa Shi Signed-off-by: Thomas Gleixner Reviewed-by: Stephen Boyd Link: https://syzkaller.appspot.com/bug?id=22c8a5938eab640d1c6bcc0e3dc7be519d878462 Link: https://lore.kernel.org/lkml/20230303161906.831686-1-schspa@gmail.com Link: https://lore.kernel.org/r/87zg7dzgao.ffs@tglx Signed-off-by: Sasha Levin

kunit: fix bug in the order of lines in debugfs logs

2023-05-11T14:10:55Z

[ Upstream commit f9a301c3317daa921375da0aec82462ddf019928 ] Fix bug in debugfs logs that causes an incorrect order of lines in the debugfs log. Currently, the test counts lines that show the number of tests passed, failed, and skipped, as well as any suite diagnostic lines, appear prior to the individual results, which is a bug. Ensure the order of printing for the debugfs log is correct. Additionally, add a KTAP header to so the debugfs logs can be valid KTAP. This is an example of a log prior to these fixes: KTAP version 1 # Subtest: kunit_status 1..2 # kunit_status: pass:2 fail:0 skip:0 total:2 # Totals: pass:2 fail:0 skip:0 total:2 ok 1 kunit_status_set_failure_test ok 2 kunit_status_mark_skipped_test ok 1 kunit_status Note the two lines with stats are out of order. This is the same debugfs log after the fixes (in combination with the third patch to remove the extra line): KTAP version 1 1..1 KTAP version 1 # Subtest: kunit_status 1..2 ok 1 kunit_status_set_failure_test ok 2 kunit_status_mark_skipped_test # kunit_status: pass:2 fail:0 skip:0 total:2 # Totals: pass:2 fail:0 skip:0 total:2 ok 1 kunit_status Signed-off-by: Rae Moar Reviewed-by: David Gow Signed-off-by: Shuah Khan Signed-off-by: Sasha Levin

maple_tree: fix a potential memory leak, OOB access, or other unpredictable bug

2023-04-26T12:30:03Z

commit 1f5f12ece722aacea1769fb644f27790ede339dc upstream. In mas_alloc_nodes(), "node->node_count = 0" means to initialize the node_count field of the new node, but the node may not be a new node. It may be a node that existed before and node_count has a value, setting it to 0 will cause a memory leak. At this time, mas->alloc->total will be greater than the actual number of nodes in the linked list, which may cause many other errors. For example, out-of-bounds access in mas_pop_node(), and mas_pop_node() may return addresses that should not be used. Fix it by initializing node_count only for new nodes. Also, by the way, an if-else statement was removed to simplify the code. Link: https://lkml.kernel.org/r/20230411041005.26205-1-zhangpeng.00@bytedance.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Peng Zhang Reviewed-by: Liam R. Howlett Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

maple_tree: fix mas_empty_area() search

2023-04-26T12:30:03Z

commit 06e8fd999334bcd76b4d72d7b9206d4aea89764e upstream. The internal function of mas_awalk() was incorrectly skipping the last entry in a node, which could potentially be NULL. This is only a problem for the left-most node in the tree - otherwise that NULL would not exist. Fix mas_awalk() by using the metadata to obtain the end of the node for the loop and the logical pivot as apposed to the raw pivot value. Link: https://lkml.kernel.org/r/20230414145728.4067069-2-Liam.Howlett@oracle.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett Reported-by: Rick Edgecombe Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

maple_tree: make maple state reusable after mas_empty_area_rev()

2023-04-26T12:30:03Z

commit fad8e4291da5e3243e086622df63cb952db444d8 upstream. Stop using maple state min/max for the range by passing through pointers for those values. This will allow the maple state to be reused without resetting. Also add some logic to fail out early on searching with invalid arguments. Link: https://lkml.kernel.org/r/20230414145728.4067069-1-Liam.Howlett@oracle.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett Reported-by: Rick Edgecombe Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

maple_tree: fix write memory barrier of nodes once dead for RCU mode

2023-04-20T10:36:58Z

[ Upstream commit c13af03de46ba27674dd9fb31a17c0d480081139 ] During the development of the maple tree, the strategy of freeing multiple nodes changed and, in the process, the pivots were reused to store pointers to dead nodes. To ensure the readers see accurate pivots, the writers need to mark the nodes as dead and call smp_wmb() to ensure any readers can identify the node as dead before using the pivot values. There were two places where the old method of marking the node as dead without smp_wmb() were being used, which resulted in RCU readers seeing the wrong pivot value before seeing the node was dead. Fix this race condition by using mte_set_node_dead() which has the smp_wmb() call to ensure the race is closed. Add a WARN_ON() to the ma_free_rcu() call to ensure all nodes being freed are marked as dead to ensure there are no other call paths besides the two updated paths. This is necessary for the RCU mode of the maple tree. Link: https://lkml.kernel.org/r/20230227173632.3292573-6-surenb@google.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett Signed-off-by: Suren Baghdasaryan Cc: Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

maple_tree: add RCU lock checking to rcu callback functions

2023-04-13T15:02:59Z

commit 790e1fa86b340c2bd4a327e01c161f7a1ad885f6 upstream. Dereferencing RCU objects within the RCU callback without the RCU check has caused lockdep to complain. Fix the RCU dereferencing by using the RCU callback lock to ensure the operation is safe. Also stop creating a new lock to use for dereferencing during destruction of the tree or subtree. Instead, pass through a pointer to the tree that has the lock that is held for RCU dereferencing checking. It also does not make sense to use the maple state in the freeing scenario as the tree walk is a special case where the tree no longer has the normal encodings and parent pointers. Link: https://lkml.kernel.org/r/20230227173632.3292573-8-surenb@google.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Cc: stable@vger.kernel.org Reported-by: Suren Baghdasaryan Signed-off-by: Liam R. Howlett Signed-off-by: Greg Kroah-Hartman

maple_tree: add smp_rmb() to dead node detection

2023-04-13T15:02:59Z

commit 0a2b18d948838e16912b3b627b504ab062b7d02a upstream. Add an smp_rmb() before reading the parent pointer to ensure that anything read from the node prior to the parent pointer hasn't been reordered ahead of this check. The is necessary for RCU mode. Link: https://lkml.kernel.org/r/20230227173632.3292573-7-surenb@google.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Cc: stable@vger.kernel.org Signed-off-by: Liam R. Howlett Signed-off-by: Greg Kroah-Hartman

maple_tree: remove extra smp_wmb() from mas_dead_leaves()

2023-04-13T15:02:58Z

commit 8372f4d83f96f35915106093cde4565836587123 upstream. The call to mte_set_dead_node() before the smp_wmb() already calls smp_wmb() so this is not needed. This is an optimization for the RCU mode of the maple tree. Link: https://lkml.kernel.org/r/20230227173632.3292573-5-surenb@google.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Cc: stable@vger.kernel.org Signed-off-by: Liam Howlett Signed-off-by: Greg Kroah-Hartman