Messages in this thread | | | Date | Thu, 25 Jul 2019 19:04:28 +0100 | From | Al Viro <> | Subject | Re: [LTP] 56cbb429d9: ltp.fs_fill.fail |
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On Thu, Jul 25, 2019 at 09:32:13AM -0700, Linus Torvalds wrote: > On Thu, Jul 25, 2019 at 6:26 AM Cyril Hrubis <chrubis@suse.cz> wrote: > > > > This looks like mkfs.vfat got EBUSY after the loop device was > > succesfully umounted. > > Hmm. Smells like the RCU-delaying got triggered again. > > We have that "synchronize_rcu_expedited()" in namespace_unlock(), > which is so that everything should be done by the time we return to > user space. > > Al, maybe that RCU synchronization should be after the mntput()s?
There are several interesting issues in there, but synchronize_rcu() should be between zeroing ->mnt_ns and dropping the final refs. I'm digging through that crap right now; at least one bug is dealt with by #fixes, but there's more, unfortunately.
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