[Bug tapsets/18856] New: nfsd.close probe alias fails on rawhide

[Bug tapsets/18856] New: nfsd.close probe alias fails on rawhide

[dsmith at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=18856

            Bug ID: 18856
           Summary: nfsd.close probe alias fails on rawhide
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: tapsets
          Assignee: systemtap at sourceware dot org
          Reporter: dsmith at redhat dot com
  Target Milestone: ---

On rawhide (4.2.0-0.rc6.git1.1.fc24.x86_64), the nfsd.close probe alias no
longer resolves:

====
# stap -p4 -e 'probe nfsd.close {}'
semantic error: while resolving probe point: identifier 'nfsd' at <input>:1:7
        source: probe nfsd.close {}
                      ^

semantic error: no match

Pass 2: analysis failed.  [man error::pass2]
====

This is because of the following kernel commit:

====
commit fd891454609ec036dc23e34536e45d655b4ca4db
Author: Christoph Hellwig <hch@lst.de>
Date:   Tue Apr 28 15:41:16 2015 +0200

    nfsd: remove nfsd_close

    Signed-off-by: Christoph Hellwig <hch@lst.de>
    Signed-off-by: J. Bruce Fields <bfields@redhat.com>
====

Here's a link to the actual patch:

<https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/fs/nfsd/vfs.c?id=fd891454609ec036dc23e34536e45d655b4ca4db>

As you can see in that patch, the nfsd_close() function was replace with a call
to fput(). We can't just move the nfsd.close probe to probe fput(), since
fput() is called all over the kernel.

So, basically this function we were probing is gone. The only solution I see at
this point is to make the nfsd.close probe point optional.

-- 
You are receiving this mail because:
You are the assignee for the bug.

[Bug tapsets/18856] nfsd.close probe alias fails on rawhide

[dsmith at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=18856

--- Comment #1 from David Smith <dsmith at redhat dot com> ---
Note that I've looked through fput()'s source, but couldn't find a suitable
callback to probe instead of nfsd_close(). fsnotify_close() might be a
candidate, but it is an inline and its arg isn't available on some kernels. The
other candidate would be file->f_op->release(), but the nfsd subsystem seems to
use generic callbacks there.

-- 
You are receiving this mail because:
You are the assignee for the bug.

[Bug tapsets/18856] nfsd.close probe alias fails on rawhide

[dsmith at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=18856

David Smith <dsmith at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #2 from David Smith <dsmith at redhat dot com> ---
Fixed (really the problem was just worked around) in commit 3fc11ed.

-- 
You are receiving this mail because:
You are the assignee for the bug.