From: Yuwen Chen <chenyuwen1@meizu.com> To: <hsiangkao@linux.alibaba.com> Cc: <chenyuwen1@meizu.com>, <linux-erofs@lists.ozlabs.org>, <linux-kernel@vger.kernel.org>, <xiang@kernel.org>, <zbestahu@gmail.com> Subject: [PATCH] erofs: wake up all waiters after z_erofs_lzma_head ready Date: Mon, 27 Jun 2022 06:40:41 +0800 [thread overview] Message-ID: <20220626224041.4288-1-chenyuwen1@meizu.com> (raw) In-Reply-To: <YrlLA5kDpprL0klA@B-P7TQMD6M-0146.local> 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> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.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
WARNING: multiple messages have this Message-ID (diff)
From: Yuwen Chen <chenyuwen1@meizu.com> To: <hsiangkao@linux.alibaba.com> Cc: linux-erofs@lists.ozlabs.org, chenyuwen1@meizu.com, linux-kernel@vger.kernel.org Subject: [PATCH] erofs: wake up all waiters after z_erofs_lzma_head ready Date: Mon, 27 Jun 2022 06:40:41 +0800 [thread overview] Message-ID: <20220626224041.4288-1-chenyuwen1@meizu.com> (raw) In-Reply-To: <YrlLA5kDpprL0klA@B-P7TQMD6M-0146.local> 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> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.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
next prev parent reply other threads:[~2022-06-27 6:41 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-06-25 14:50 [PATCH] erofs: Wake up all waiters after z_erofs_lzma_head ready Yuwen Chen 2022-06-25 14:50 ` Yuwen Chen 2022-06-27 2:56 ` Gao Xiang 2022-06-27 2:56 ` Gao Xiang 2022-06-27 5:57 ` Yue Hu 2022-06-27 5:57 ` Yue Hu 2022-06-27 6:15 ` Gao Xiang 2022-06-27 6:15 ` Gao Xiang 2022-06-26 22:40 ` Yuwen Chen [this message] 2022-06-26 22:40 ` [PATCH] erofs: wake " Yuwen Chen 2022-06-27 7:11 ` 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 13:18 ` Even 2022-06-25 8:57 Even 2022-06-25 8:57 ` Even 2022-06-25 9:44 ` Gao Xiang 2022-06-25 9:44 ` Gao Xiang
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