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* [PATCH] erofs: Wake up all waiters after z_erofs_lzma_head ready.
@ 2022-06-25 14:50 Yuwen Chen
  2022-06-27  2:56 ` Gao Xiang
  2022-06-27  5:57 ` Yue Hu
  0 siblings, 2 replies; 9+ messages in thread
From: Yuwen Chen @ 2022-06-25 14:50 UTC (permalink / raw)
  To: xiang; +Cc: chao, linux-erofs, linux-kernel, Yuwen Chen

When the user mounts the erofs second times, the decompression thread
may hung. The problem happens due to a sequence of steps like the
following:

1) Task A called z_erofs_load_lzma_config which obtain all of the node
   from the z_erofs_lzma_head.

2) At this time, task B called the z_erofs_lzma_decompress and wanted to
   get a node. But the z_erofs_lzma_head was empty, the Task B had to
   sleep.

3) Task A release nodes and push nodes into the z_erofs_lzma_head. But
   task B was still sleeping.

One example report when the hung happens:
task:kworker/u3:1 state:D stack:14384 pid: 86 ppid: 2 flags:0x00004000
Workqueue: erofs_unzipd z_erofs_decompressqueue_work
Call Trace:
 <TASK>
 __schedule+0x281/0x760
 schedule+0x49/0xb0
 z_erofs_lzma_decompress+0x4bc/0x580
 ? cpu_core_flags+0x10/0x10
 z_erofs_decompress_pcluster+0x49b/0xba0
 ? __update_load_avg_se+0x2b0/0x330
 ? __update_load_avg_se+0x2b0/0x330
 ? update_load_avg+0x5f/0x690
 ? update_load_avg+0x5f/0x690
 ? set_next_entity+0xbd/0x110
 ? _raw_spin_unlock+0xd/0x20
 z_erofs_decompress_queue.isra.0+0x2e/0x50
 z_erofs_decompressqueue_work+0x30/0x60
 process_one_work+0x1d3/0x3a0
 worker_thread+0x45/0x3a0
 ? process_one_work+0x3a0/0x3a0
 kthread+0xe2/0x110
 ? kthread_complete_and_exit+0x20/0x20
 ret_from_fork+0x22/0x30
 </TASK>

Signed-off-by: Yuwen Chen <chenyuwen1@meizu.com>
---
 fs/erofs/decompressor_lzma.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/erofs/decompressor_lzma.c b/fs/erofs/decompressor_lzma.c
index 05a3063cf2bc..5e59b3f523eb 100644
--- a/fs/erofs/decompressor_lzma.c
+++ b/fs/erofs/decompressor_lzma.c
@@ -143,6 +143,7 @@ int z_erofs_load_lzma_config(struct super_block *sb,
 	DBG_BUGON(z_erofs_lzma_head);
 	z_erofs_lzma_head = head;
 	spin_unlock(&z_erofs_lzma_lock);
+	wake_up_all(&z_erofs_lzma_wq);
 
 	z_erofs_lzma_max_dictsize = dict_size;
 	mutex_unlock(&lzma_resize_mutex);
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread
* [PATCH] erofs: Wake up all waiters after z_erofs_lzma_head ready.
@ 2022-06-25 13:18 Even
  0 siblings, 0 replies; 9+ messages in thread
From: Even @ 2022-06-25 13:18 UTC (permalink / raw)
  To: xiang; +Cc: chao, linux-erofs, linux-kernel, Even

When the user mounts the erofs second times, the decompression thread
may hung. The problem happens due to a sequence of steps like the
following:

1) Task A called z_erofs_load_lzma_config which obtain all of the node
   from the z_erofs_lzma_head.

2) At this time, task B called the z_erofs_lzma_decompress and wanted to
   get a node. But the z_erofs_lzma_head was empty, the Task B had to
   sleep.

3) Task A release nodes and push nodes into the z_erofs_lzma_head. But
   task B was still sleeping.

One example report when the hung happens:
task:kworker/u3:1 state:D stack:14384 pid: 86 ppid: 2 flags:0x00004000
Workqueue: erofs_unzipd z_erofs_decompressqueue_work
Call Trace:
 <TASK>
 __schedule+0x281/0x760
 schedule+0x49/0xb0
 z_erofs_lzma_decompress+0x4bc/0x580
 ? cpu_core_flags+0x10/0x10
 z_erofs_decompress_pcluster+0x49b/0xba0
 ? __update_load_avg_se+0x2b0/0x330
 ? __update_load_avg_se+0x2b0/0x330
 ? update_load_avg+0x5f/0x690
 ? update_load_avg+0x5f/0x690
 ? set_next_entity+0xbd/0x110
 ? _raw_spin_unlock+0xd/0x20
 z_erofs_decompress_queue.isra.0+0x2e/0x50
 z_erofs_decompressqueue_work+0x30/0x60
 process_one_work+0x1d3/0x3a0
 worker_thread+0x45/0x3a0
 ? process_one_work+0x3a0/0x3a0
 kthread+0xe2/0x110
 ? kthread_complete_and_exit+0x20/0x20
 ret_from_fork+0x22/0x30
 </TASK>

Signed-off-by: Even <chenyuwen1@meizu.com>
---
 fs/erofs/decompressor_lzma.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/erofs/decompressor_lzma.c b/fs/erofs/decompressor_lzma.c
index 05a3063cf2bc..5e59b3f523eb 100644
--- a/fs/erofs/decompressor_lzma.c
+++ b/fs/erofs/decompressor_lzma.c
@@ -143,6 +143,7 @@ int z_erofs_load_lzma_config(struct super_block *sb,
 	DBG_BUGON(z_erofs_lzma_head);
 	z_erofs_lzma_head = head;
 	spin_unlock(&z_erofs_lzma_lock);
+	wake_up_all(&z_erofs_lzma_wq);
 
 	z_erofs_lzma_max_dictsize = dict_size;
 	mutex_unlock(&lzma_resize_mutex);
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread
* [PATCH] erofs: Wake up all waiters after z_erofs_lzma_head ready.
@ 2022-06-25  8:57 Even
  2022-06-25  9:44 ` Gao Xiang
  0 siblings, 1 reply; 9+ messages in thread
From: Even @ 2022-06-25  8:57 UTC (permalink / raw)
  To: xiang; +Cc: chao, linux-erofs, linux-kernel, Even

From: Even <chenyuwen1@meizu.com>

When the user mounts the erofs second times, the decompression thread
may hung. The problem happens due to a sequence of steps like the
following:

1) Task A called z_erofs_load_lzma_config which obtain all of the node
   from the z_erofs_lzma_head.

2) At this time, task B called the z_erofs_lzma_decompress and wanted to
   get a node. But the z_erofs_lzma_head was empty, the Task B had to
   sleep.

3) Task A release nodes and push nodes into the z_erofs_lzma_head. But
   task B was still sleeping.

One example report when the hung happens:
task:kworker/u3:1 state:D stack:14384 pid: 86 ppid: 2 flags:0x00004000
Workqueue: erofs_unzipd z_erofs_decompressqueue_work
Call Trace:
 <TASK>
 __schedule+0x281/0x760
 schedule+0x49/0xb0
 z_erofs_lzma_decompress+0x4bc/0x580
 ? cpu_core_flags+0x10/0x10
 z_erofs_decompress_pcluster+0x49b/0xba0
 ? __update_load_avg_se+0x2b0/0x330
 ? __update_load_avg_se+0x2b0/0x330
 ? update_load_avg+0x5f/0x690
 ? update_load_avg+0x5f/0x690
 ? set_next_entity+0xbd/0x110
 ? _raw_spin_unlock+0xd/0x20
 z_erofs_decompress_queue.isra.0+0x2e/0x50
 z_erofs_decompressqueue_work+0x30/0x60
 process_one_work+0x1d3/0x3a0
 worker_thread+0x45/0x3a0
 ? process_one_work+0x3a0/0x3a0
 kthread+0xe2/0x110
 ? kthread_complete_and_exit+0x20/0x20
 ret_from_fork+0x22/0x30
 </TASK>

Signed-off-by: Even <chenyuwen1@meizu.com>
---
 fs/erofs/decompressor_lzma.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/erofs/decompressor_lzma.c b/fs/erofs/decompressor_lzma.c
index 05a3063cf2bc..5e59b3f523eb 100644
--- a/fs/erofs/decompressor_lzma.c
+++ b/fs/erofs/decompressor_lzma.c
@@ -143,6 +143,7 @@ int z_erofs_load_lzma_config(struct super_block *sb,
 	DBG_BUGON(z_erofs_lzma_head);
 	z_erofs_lzma_head = head;
 	spin_unlock(&z_erofs_lzma_lock);
+	wake_up_all(&z_erofs_lzma_wq);
 
 	z_erofs_lzma_max_dictsize = dict_size;
 	mutex_unlock(&lzma_resize_mutex);
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2022-06-27  7:11 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-06-25 14:50 [PATCH] erofs: Wake up all waiters after z_erofs_lzma_head ready Yuwen Chen
2022-06-27  2:56 ` Gao Xiang
2022-06-27  5:57 ` Yue Hu
2022-06-27  6:15   ` Gao Xiang
2022-06-26 22:40     ` [PATCH] erofs: wake " Yuwen Chen
2022-06-27  7:11       ` Yuwen Chen
  -- strict thread matches above, loose matches on Subject: below --
2022-06-25 13:18 [PATCH] erofs: Wake " Even
2022-06-25  8:57 Even
2022-06-25  9:44 ` Gao Xiang

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