diff --git a/arch/arm64/configs/vendor/lahaina_debug.config b/arch/arm64/configs/vendor/lahaina_debug.config
index 5c4e6997067e..4661a42fb3f7 100644
--- a/arch/arm64/configs/vendor/lahaina_debug.config
+++ b/arch/arm64/configs/vendor/lahaina_debug.config
@@ -10,6 +10,7 @@ CONFIG_DEBUG_PAGEALLOC=y
 CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT=y
 CONFIG_PAGE_POISONING=y
 CONFIG_PAGE_POISONING_ENABLE_DEFAULT=y
+CONFIG_PAGE_EXTENSION_PAGE_FREE=y
 # CONFIG_DEBUG_DMA_BUF_REF is not set
 # CONFIG_PAGE_POISONING_NO_SANITY is not set
 # CONFIG_PAGE_POISONING_ZERO is not set
diff --git a/include/linux/oom.h b/include/linux/oom.h
index 40862dd4f223..c880273c6199 100644
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -130,4 +130,6 @@ extern int sysctl_reap_mem_on_sigkill;
 
 /* calls for LMK reaper */
 extern void add_to_oom_reaper(struct task_struct *p);
+extern void check_panic_on_foreground_kill(struct task_struct *p);
+#define ULMK_MAGIC "lmkd"
 #endif /* _INCLUDE_LINUX_OOM_H */
diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h
index cfce186f0c4e..e50acd1810c9 100644
--- a/include/linux/page_ext.h
+++ b/include/linux/page_ext.h
@@ -19,6 +19,9 @@ struct page_ext_operations {
 enum page_ext_flags {
 	PAGE_EXT_OWNER,
 	PAGE_EXT_OWNER_ALLOCATED,
+#ifdef CONFIG_PAGE_EXTENSION_PAGE_FREE
+	PAGE_EXT_PG_FREE,
+#endif
 #if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT)
 	PAGE_EXT_YOUNG,
 	PAGE_EXT_IDLE,
diff --git a/kernel/signal.c b/kernel/signal.c
index e8f1ce7a7e47..1ae3e276e51b 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1406,6 +1406,7 @@ int group_send_sig_info(int sig, struct kernel_siginfo *info,
 	rcu_read_unlock();
 
 	if (!ret && sig) {
+		check_panic_on_foreground_kill(p);
 		ret = do_send_sig_info(sig, info, p, type);
 		if (capable(CAP_KILL) && sig == SIGKILL)
 			add_to_oom_reaper(p);
diff --git a/mm/Kconfig b/mm/Kconfig
index 4a8b6d55ae4d..2c5a3693e769 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -759,6 +759,17 @@ config PERCPU_STATS
 	  information includes global and per chunk statistics, which can
 	  be used to help understand percpu memory usage.
 
+config HAVE_USERSPACE_LOW_MEMORY_KILLER
+	bool "Configure reclaim paths if there is a userspace LMK"
+	default n
+	help
+	  Configures parts of the reclaim paths in the kernel when Android
+	  has a userspace memory killer.  This configuration is done for
+	  functional (e.g. ensuring the OOM killer doesn't run at certain
+	  points) and performance purposes (e.g. preventing log-spew
+	  when the OOM killer and userspace memory killer both have the
+	  potential to run).
+
 config GUP_BENCHMARK
 	bool "Enable infrastructure for get_user_pages_fast() benchmarking"
 	help
diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
index 46615e0bdb35..14e36729c3d6 100644
--- a/mm/Kconfig.debug
+++ b/mm/Kconfig.debug
@@ -8,6 +8,15 @@ config PAGE_EXTENSION
 	  by not allocating this extra memory according to boottime
 	  configuration.
 
+config PAGE_EXTENSION_PAGE_FREE
+	bool "Add a flag in page_ext_flags to indicate if a page is free"
+	depends on PAGE_EXTENSION && QGKI
+	help
+	  Add the PAGE_FREE flag in page_ext_flags, in order to indicate
+	  whether a page from the buddy allocator is free or is in
+	  use.  This information can aid in debugging buddy allocator
+	  related issues.
+
 config DEBUG_PAGEALLOC
 	bool "Debug page memory allocations"
 	depends on DEBUG_KERNEL
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index c19945135938..d0cece9bdd15 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -58,6 +58,9 @@ int sysctl_oom_kill_allocating_task;
 int sysctl_oom_dump_tasks = 1;
 int sysctl_reap_mem_on_sigkill = 1;
 
+static int panic_on_adj_zero;
+module_param(panic_on_adj_zero, int, 0644);
+
 /*
  * Serializes oom killer invocations (out_of_memory()) from all contexts to
  * prevent from over eager oom killing (e.g. when the oom killer is invoked
@@ -1155,8 +1158,7 @@ void pagefault_out_of_memory(void)
 		.order = 0,
 	};
 
-	if (IS_ENABLED(CONFIG_HAVE_LOW_MEMORY_KILLER) ||
-	    IS_ENABLED(CONFIG_HAVE_USERSPACE_LOW_MEMORY_KILLER))
+	if (IS_ENABLED(CONFIG_HAVE_USERSPACE_LOW_MEMORY_KILLER))
 		return;
 
 	if (mem_cgroup_oom_synchronize(true))
@@ -1197,3 +1199,18 @@ void add_to_oom_reaper(struct task_struct *p)
 
 	put_task_struct(p);
 }
+
+/*
+ * Should be called prior to sending sigkill. To guarantee that the
+ * process to-be-killed is still untouched.
+ */
+void check_panic_on_foreground_kill(struct task_struct *p)
+{
+	if (unlikely(!strcmp(current->comm, ULMK_MAGIC)
+			&& p->signal->oom_score_adj == 0
+			&& panic_on_adj_zero)) {
+		show_mem(SHOW_MEM_FILTER_NODES, NULL);
+		show_mem_call_notifiers();
+		panic("Attempt to kill foreground task: %s", p->comm);
+	}
+}
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 41a99cfe0b0d..35673f47d8af 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -29,6 +29,7 @@ struct page_owner {
 	depot_stack_handle_t free_handle;
 	int pid;
 	u64 ts_nsec;
+	u64 free_ts_nsec;
 };
 
 static bool page_owner_enabled = IS_ENABLED(CONFIG_PAGE_OWNER_ENABLE_DEFAULT);
@@ -152,6 +153,7 @@ void __reset_page_owner(struct page *page, unsigned int order)
 	struct page_ext *page_ext;
 	depot_stack_handle_t handle = 0;
 	struct page_owner *page_owner;
+	u64 free_ts_nsec = local_clock();
 
 	handle = save_stack(GFP_NOWAIT | __GFP_NOWARN);
 
@@ -160,8 +162,12 @@ void __reset_page_owner(struct page *page, unsigned int order)
 		return;
 	for (i = 0; i < (1 << order); i++) {
 		__clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
+#ifdef CONFIG_PAGE_EXTENSION_PAGE_FREE
+		__set_bit(PAGE_EXT_PG_FREE, &page_ext->flags);
+#endif
 		page_owner = get_page_owner(page_ext);
 		page_owner->free_handle = handle;
+		page_owner->free_ts_nsec = free_ts_nsec;
 		page_ext = page_ext_next(page_ext);
 	}
 }
@@ -181,8 +187,13 @@ static inline void __set_page_owner_handle(struct page *page,
 		page_owner->last_migrate_reason = -1;
 		page_owner->pid = current->pid;
 		page_owner->ts_nsec = local_clock();
+		page_owner->free_ts_nsec = 0;
+
 		__set_bit(PAGE_EXT_OWNER, &page_ext->flags);
 		__set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
+#ifdef CONFIG_PAGE_EXTENSION_PAGE_FREE
+		__clear_bit(PAGE_EXT_PG_FREE, &page_ext->flags);
+#endif
 
 		page_ext = page_ext_next(page_ext);
 	}
@@ -247,6 +258,7 @@ void __copy_page_owner(struct page *oldpage, struct page *newpage)
 	new_page_owner->handle = old_page_owner->handle;
 	new_page_owner->pid = old_page_owner->pid;
 	new_page_owner->ts_nsec = old_page_owner->ts_nsec;
+	new_page_owner->free_ts_nsec = old_page_owner->ts_nsec;
 
 	/*
 	 * We don't clear the bit on the oldpage as it's going to be freed