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authorYuwen Chen <chenyuwen1@meizu.com>2022-06-27 01:40:41 +0300
committerGao Xiang <hsiangkao@linux.alibaba.com>2022-07-09 01:32:29 +0300
commit2df7c4bd7c1d2bc5ece5e9ed19dbd386810c2a65 (patch)
tree07ba6bbc825183db80b8fde7705eb8d3eac18b09 /fs/erofs/decompressor_lzma.c
parentf94bc517b4992aeddeeb30a4ac813cb4d1d81241 (diff)
downloadlinux-2df7c4bd7c1d2bc5ece5e9ed19dbd386810c2a65.tar.xz
erofs: wake up all waiters after z_erofs_lzma_head ready
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> Fixes: 622ceaddb764 ("erofs: lzma compression support") Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20220626224041.4288-1-chenyuwen1@meizu.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Diffstat (limited to 'fs/erofs/decompressor_lzma.c')
-rw-r--r--fs/erofs/decompressor_lzma.c1
1 files changed, 1 insertions, 0 deletions
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 @@ again:
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);