linux-kernel - Re: [syzbot] [jfs?] INFO: task hung in txBegin

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Message-ID: <tencent_48AA749F76BD66F03C5F3724972036684A09@qq.com>
Date: Mon,  5 Aug 2024 19:46:43 +0800
From: Edward Adam Davis <eadavis@...com>
To: syzbot+eda89a33c5856f66f823@...kaller.appspotmail.com
Cc: linux-kernel@...r.kernel.org,
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [jfs?] INFO: task hung in txBegin

with sb rwsem lock to order syncfs and wb worker

#syz test: upstream 50736169ecc8

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index b865a3fa52f3..682c5a237edc 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -985,6 +985,7 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
 	struct bdi_writeback *last_wb = NULL;
 	struct bdi_writeback *wb = list_entry(&bdi->wb_list,
 					      struct bdi_writeback, bdi_node);
+	bool no_queue = true;
 
 	might_sleep();
 restart:
@@ -1015,6 +1016,7 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
 			*work = *base_work;
 			work->nr_pages = nr_pages;
 			work->auto_free = 1;
+			no_queue = false;
 			wb_queue_work(wb, work);
 			continue;
 		}
@@ -1043,6 +1045,12 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
 		wb_wait_for_completion(&fallback_work_done);
 		goto restart;
 	}
+
+	if (no_queue) {
+		printk("no queue\n");
+		base_work->auto_free = 1;
+		finish_writeback_work(base_work);
+	}
 	rcu_read_unlock();
 
 	if (last_wb)