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From: Marko Rauhamaa <marko.rauhamaa@f-secure.com>
To: Amir Goldstein <amir73il@gmail.com>
CC: linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Jan Kara <jack@suse.cz>
Subject: Re: Reproducible, long-standing fanotify+autofs problem
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Date: Thu, 26 Jan 2017 20:05:56 +0200
In-Reply-To: <87sho5r9v9.fsf@drapion.f-secure.com> (Marko Rauhamaa's message
        of "Thu, 26 Jan 2017 19:47:54 +0200")
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Marko Rauhamaa <marko.rauhamaa@f-secure.com>:
> I have dug a bit deeper. What hangs is this statement:
>
>     mnt = path->dentry->d_op->d_automount(path);
>
> in:
>
>     follow_automount() // fs/namei.c
>       called from: follow_managed()
        called from: lookup_fast()
>       called from: walk_component()
>       called from: lookup_last()
>       called from: path_lookupat()
>       called from: filename_lookup()
>       called from: user_path_at_empty()
>       called from: user_path_at(filename="/sshome/test/user/", lookup_flags=0x1)
>       called from: fanotify_find_path() // fs/notify/fanotify_user.c
>       called from: fanotify_mark()
>
> And Ctrl-C wakes it up.
>
> The d_automount() method is bound to autofs4_d_automount() in
> fs/autofs4/root.c. The hanging statement is:
>
>      wait_event_interruptible(wq->queue, wq->name.name == NULL);
>
> in:
>
>     autofs4_wait() // fs/autofs4/waitq.c
>       called from: autofs4_mount_wait() // fs/autofs4/root.c
>       called from: autofs4_d_automount()

Added a missing call to the call trace.


Marko