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Date:   Tue, 14 Nov 2023 14:19:34 +0100
From:   Herve Codina <herve.codina@bootlin.com>
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     Saravana Kannan <saravanak@google.com>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        linux-kernel@vger.kernel.org,
        Allan Nielsen <allan.nielsen@microchip.com>,
        Horatiu Vultur <horatiu.vultur@microchip.com>,
        Steen Hegelund <steen.hegelund@microchip.com>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        stable@vger.kernel.org
Subject: Re: [PATCH 1/1] lib/vsprintf: Fix %pfwf when current node refcount
 == 0
Message-ID: <20231114141934.1b0d44e2@bootlin.com>
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        <ZVNyT6qTw6mpy6BY@smile.fi.intel.com>
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On Tue, 14 Nov 2023 15:12:47 +0200
Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

> On Tue, Nov 14, 2023 at 12:04:56PM +0100, Herve Codina wrote:
> > A refcount issue can appeared in __fwnode_link_del() due to the
> > pr_debug() call:  
> 
> >   WARNING: CPU: 0 PID: 901 at lib/refcount.c:25 refcount_warn_saturate+0xe5/0x110
> >   Call Trace:
> >   <TASK>
> >   ? refcount_warn_saturate+0xe5/0x110
> >   ? __warn+0x81/0x130
> >   ? refcount_warn_saturate+0xe5/0x110
> >   ? report_bug+0x191/0x1c0
> >   ? srso_alias_return_thunk+0x5/0x7f
> >   ? prb_read_valid+0x1b/0x30
> >   ? handle_bug+0x3c/0x80
> >   ? exc_invalid_op+0x17/0x70
> >   ? asm_exc_invalid_op+0x1a/0x20
> >   ? refcount_warn_saturate+0xe5/0x110
> >   kobject_get+0x68/0x70
> >   of_node_get+0x1e/0x30
> >   of_fwnode_get+0x28/0x40
> >   fwnode_full_name_string+0x34/0x90
> >   fwnode_string+0xdb/0x140
> >   vsnprintf+0x17b/0x630
> >   va_format.isra.0+0x71/0x130
> >   vsnprintf+0x17b/0x630
> >   vprintk_store+0x162/0x4d0
> >   ? srso_alias_return_thunk+0x5/0x7f
> >   ? srso_alias_return_thunk+0x5/0x7f
> >   ? srso_alias_return_thunk+0x5/0x7f
> >   ? try_to_wake_up+0x9c/0x620
> >   ? rwsem_mark_wake+0x1b2/0x310
> >   vprintk_emit+0xe4/0x2b0
> >   _printk+0x5c/0x80
> >   __dynamic_pr_debug+0x131/0x160
> >   ? srso_alias_return_thunk+0x5/0x7f
> >   __fwnode_link_del+0x25/0xa0
> >   fwnode_links_purge+0x39/0xb0
> >   of_node_release+0xd9/0x180
> >   kobject_put+0x7b/0x190
> >   ...  
> 
> Please, do not put so many unrelated lines of backtrace in the commit message.
> Leave only the important ones (the Submitting Patches document suggests some
> like ~3-5 lines only).

Ok, I will remove some of them.

Best regards,
Hervé