Messages in this thread | | | Subject | Re: INFO: task hung in __get_super | From | Tetsuo Handa <> | Date | Tue, 19 Jun 2018 20:44:57 +0900 |
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This bug report is getting no feedback, but I guess that this bug is in block or mm or locking layer rather than fs layer.
NMI backtrace for this bug tends to report that sb_bread() from fill_super() from mount_bdev() is stalling is the cause of keep holding s_umount_key for more than 120 seconds. What is strange is that NMI backtrace for this bug tends to point at rcu_read_lock()/pagecache_get_page()/radix_tree_deref_slot()/ rcu_read_unlock() which is expected not to stall.
Since CONFIG_RCU_CPU_STALL_TIMEOUT is set to 120 (and actually +5 due to CONFIG_PROVE_RCU=y) which is longer than CONFIG_DEFAULT_HUNG_TASK_TIMEOUT, maybe setting CONFIG_RCU_CPU_STALL_TIMEOUT to smaller values (e.g. 25) can give us some hints...
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