From eaf14f852ae79f7745934e213661f1c6abac711e Mon Sep 17 00:00:00 2001

From: Greg Edwards <gedwards@ddn.com>

Date: Wed, 23 Jun 2021 13:50:47 -0600

Subject: [PATCH] Fix 'waitq' command for Linux 4.13 and later kernels

The wait queue structs and members were renamed in 4.13 in commits:

  ac6424b981bc ("sched/wait: Rename wait_queue_t => wait_queue_entry_t")

  9d9d676f595b ("sched/wait: Standardize internal naming of wait-queue heads")

  2055da97389a ("sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list naming")

Add support to the 'waitq' command for these more recent kernels.

[ kh: suppressed compilation warnings ]

Signed-off-by: Greg Edwards <gedwards@ddn.com>

Signed-off-by: Kazuhito Hagio <k-hagio-ab@nec.com>

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>

---

 defs.h    |  4 ++++

 kernel.c  | 27 +++++++++++++++++++++++----

 symbols.c | 10 +++++++++-

 3 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/defs.h b/defs.h

index 42c8074e6ac6..6bb00e29d811 100644

--- a/defs.h

+++ b/defs.h

@@ -2138,6 +2138,9 @@ struct offset_table {                    /* stash of commonly-used offsets */

 	long atomic_long_t_counter;

 	long block_device_bd_device;

 	long block_device_bd_stats;

+	long wait_queue_entry_private;

+	long wait_queue_head_head;

+	long wait_queue_entry_entry;

 };

 struct size_table {         /* stash of commonly-used sizes */

@@ -2300,6 +2303,7 @@ struct size_table {         /* stash of commonly-used sizes */

 	long printk_info;

 	long printk_ringbuffer;

 	long prb_desc;

+	long wait_queue_entry;

 };

 struct array_table {

diff --git a/kernel.c b/kernel.c

index 528f6ee524f6..e123f760e036 100644

--- a/kernel.c

+++ b/kernel.c

@@ -615,7 +615,15 @@ kernel_init()

 		kt->flags |= TVEC_BASES_V1;

         STRUCT_SIZE_INIT(__wait_queue, "__wait_queue");

-        if (VALID_STRUCT(__wait_queue)) {

+	STRUCT_SIZE_INIT(wait_queue_entry, "wait_queue_entry");

+	if (VALID_STRUCT(wait_queue_entry)) {

+		MEMBER_OFFSET_INIT(wait_queue_entry_private,

+			"wait_queue_entry", "private");

+		MEMBER_OFFSET_INIT(wait_queue_head_head,

+			"wait_queue_head", "head");

+		MEMBER_OFFSET_INIT(wait_queue_entry_entry,

+			"wait_queue_entry", "entry");

+	} else if (VALID_STRUCT(__wait_queue)) {

 		if (MEMBER_EXISTS("__wait_queue", "task"))

 			MEMBER_OFFSET_INIT(__wait_queue_task,

 				"__wait_queue", "task");

@@ -9367,9 +9375,9 @@ dump_waitq(ulong wq, char *wq_name)

 	struct list_data list_data, *ld;

 	ulong *wq_list;			/* addr of wait queue element */

 	ulong next_offset;		/* next pointer of wq element */

-	ulong task_offset;		/* offset of task in wq element */

+	ulong task_offset = 0;		/* offset of task in wq element */

 	int cnt;			/* # elems on Queue */

-	int start_index;		/* where to start in wq array */

+	int start_index = -1;		/* where to start in wq array */

 	int i;

 	ld = &list_data;

@@ -9397,9 +9405,20 @@ dump_waitq(ulong wq, char *wq_name)

                 ld->list_head_offset = OFFSET(__wait_queue_task_list);

                 ld->member_offset = next_offset;

+		start_index = 1;

+	} else if (VALID_STRUCT(wait_queue_entry)) {

+		ulong head_offset;

+

+		next_offset = OFFSET(list_head_next);

+		task_offset = OFFSET(wait_queue_entry_private);

+		head_offset = OFFSET(wait_queue_head_head);

+		ld->end = ld->start = wq + head_offset + next_offset;

+		ld->list_head_offset = OFFSET(wait_queue_entry_entry);

+		ld->member_offset = next_offset;

+

 		start_index = 1;

 	} else {

-		return;

+		error(FATAL, "cannot determine wait queue structures\n");

 	}

 	hq_open();

diff --git a/symbols.c b/symbols.c

index 370d4c3e8ac0..67c135f12984 100644

--- a/symbols.c

+++ b/symbols.c

@@ -9817,7 +9817,13 @@ dump_offset_table(char *spec, ulong makestruct)

         	OFFSET(__wait_queue_head_task_list));

         fprintf(fp, "        __wait_queue_task_list: %ld\n", 

         	OFFSET(__wait_queue_task_list));

- 

+	fprintf(fp, "      wait_queue_entry_private: %ld\n",

+		OFFSET(wait_queue_entry_private));

+	fprintf(fp, "          wait_queue_head_head: %ld\n",

+		OFFSET(wait_queue_head_head));

+	fprintf(fp, "        wait_queue_entry_entry: %ld\n",

+		OFFSET(wait_queue_entry_entry));

+

 	fprintf(fp, "        pglist_data_node_zones: %ld\n",

 		OFFSET(pglist_data_node_zones));

 	fprintf(fp, "      pglist_data_node_mem_map: %ld\n",

@@ -10717,6 +10723,8 @@ dump_offset_table(char *spec, ulong makestruct)

 	fprintf(fp, "                    wait_queue: %ld\n", SIZE(wait_queue));

 	fprintf(fp, "                  __wait_queue: %ld\n", 

 		SIZE(__wait_queue));

+	fprintf(fp, "              wait_queue_entry: %ld\n",

+		SIZE(wait_queue_entry));

 	fprintf(fp, "                        device: %ld\n", SIZE(device));

 	fprintf(fp, "                    net_device: %ld\n", SIZE(net_device));

-- 

2.30.2