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Date:   Thu, 23 Nov 2023 17:06:03 +0100
From:   Heiko Carstens <hca@linux.ibm.com>
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Ajay Kaher <akaher@vmware.com>, chinglinyu@google.com,
        lkp@intel.com, namit@vmware.com, oe-lkp@lists.linux.dev,
        amakhalov@vmware.com, er.ajay.kaher@gmail.com,
        srivatsa@csail.mit.edu, tkundu@vmware.com, vsirnapalli@vmware.com,
        linux-s390@vger.kernel.org
Subject: Re: [PATCH v5] eventfs: Remove eventfs_file and just use
 eventfs_inode
Message-ID: <20231123160603.9603-B-hca@linux.ibm.com>
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On Thu, Nov 23, 2023 at 10:23:49AM -0500, Steven Rostedt wrote:
> On Thu, 23 Nov 2023 12:25:48 +0100
> Heiko Carstens <hca@linux.ibm.com> wrote:
> 
> > So, if it helps (this still happens with Linus' master branch):
> > 
> > create_dir_dentry() is called with a "struct eventfs_inode *ei" (second
> > parameter), which points to a data structure where "is_freed" is 1. Then it
> > looks like create_dir() returned "-EEXIST". And looking at the code this
> > combination then must lead to d_invalidate() incorrectly being called with
> > "-EEXIST" as dentry pointer.
> 
> I haven't looked too much at the error codes, let me do that on Monday
> (it's currently Turkey weekend here in the US).
> 
> But could you test this branch:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git  trace/core
> 
> I have a bunch of fixes in that branch that may fix your issue. I just
> finished testing it and plan on pushing it to Linus before the next rc
> release.

This is not that easy to reproduce, however you branch contains commit
71cade82f2b5 ("eventfs: Do not invalidate dentry in create_file/dir_dentry()")
which removes the d_invalidate() call.
The crash I reported cannot happen anymore with that commit. I'll consider
this fixed, and report again if this (or something else) still causes
problems.

Thanks!