linux-kernel - Re: [PATCH v6 5/5] kdb: Adapt kdb_msg

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Message-ID: <202510171450.G2KdvDMm-lkp@intel.com>
Date: Fri, 17 Oct 2025 15:14:34 +0800
From: kernel test robot <lkp@...el.com>
To: Marcos Paulo de Souza <mpdesouza@...e.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Petr Mladek <pmladek@...e.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	John Ogness <john.ogness@...utronix.de>,
	Sergey Senozhatsky <senozhatsky@...omium.org>,
	Jason Wessel <jason.wessel@...driver.com>,
	Daniel Thompson <danielt@...nel.org>,
	Douglas Anderson <dianders@...omium.org>
Cc: oe-kbuild-all@...ts.linux.dev, linux-kernel@...r.kernel.org,
	kgdb-bugreport@...ts.sourceforge.net,
	Marcos Paulo de Souza <mpdesouza@...e.com>
Subject: Re: [PATCH v6 5/5] kdb: Adapt kdb_msg_write to work with NBCON
 consoles

Hi Marcos,

kernel test robot noticed the following build errors:

[auto build test ERROR on 3a8660878839faadb4f1a6dd72c3179c1df56787]

url:    https://github.com/intel-lab-lkp/linux/commits/Marcos-Paulo-de-Souza/printk-nbcon-Export-console_is_usable/20251016-225503
base:   3a8660878839faadb4f1a6dd72c3179c1df56787
patch link:    https://lore.kernel.org/r/20251016-nbcon-kgdboc-v6-5-866aac60a80e%40suse.com
patch subject: [PATCH v6 5/5] kdb: Adapt kdb_msg_write to work with NBCON consoles
config: sh-randconfig-002-20251017 (https://download.01.org/0day-ci/archive/20251017/202510171450.G2KdvDMm-lkp@intel.com/config)
compiler: sh4-linux-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251017/202510171450.G2KdvDMm-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202510171450.G2KdvDMm-lkp@intel.com/

All errors (new ones prefixed by >>):

   kernel/debug/kdb/kdb_io.c: In function 'kdb_msg_write':
>> kernel/debug/kdb/kdb_io.c:612:43: error: passing argument 1 of 'nbcon_kdb_release' from incompatible pointer type [-Wincompatible-pointer-types]
     612 |                         nbcon_kdb_release(&wctxt);
         |                                           ^~~~~~
         |                                           |
         |                                           struct nbcon_write_context *
   In file included from kernel/debug/kdb/kdb_io.c:17:
   include/linux/console.h:667:54: note: expected 'struct console *' but argument is of type 'struct nbcon_write_context *'
     667 | static inline void nbcon_kdb_release(struct console *con) { }
         |                                      ~~~~~~~~~~~~~~~~^~~

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for I2C_K1
   Depends on [n]: I2C [=y] && HAS_IOMEM [=y] && (ARCH_SPACEMIT || COMPILE_TEST [=y]) && OF [=n]
   Selected by [y]:
   - MFD_SPACEMIT_P1 [=y] && HAS_IOMEM [=y] && (ARCH_SPACEMIT || COMPILE_TEST [=y]) && I2C [=y]


vim +/nbcon_kdb_release +612 kernel/debug/kdb/kdb_io.c

   560	
   561	static void kdb_msg_write(const char *msg, int msg_len)
   562	{
   563		struct console *c;
   564		const char *cp;
   565		int cookie;
   566		int len;
   567	
   568		if (msg_len == 0)
   569			return;
   570	
   571		cp = msg;
   572		len = msg_len;
   573	
   574		while (len--) {
   575			dbg_io_ops->write_char(*cp);
   576			cp++;
   577		}
   578	
   579		/*
   580		 * The console_srcu_read_lock() only provides safe console list
   581		 * traversal. The use of the ->write() callback relies on all other
   582		 * CPUs being stopped at the moment and console drivers being able to
   583		 * handle reentrance when @oops_in_progress is set.
   584		 *
   585		 * There is no guarantee that every console driver can handle
   586		 * reentrance in this way; the developer deploying the debugger
   587		 * is responsible for ensuring that the console drivers they
   588		 * have selected handle reentrance appropriately.
   589		 */
   590		cookie = console_srcu_read_lock();
   591		for_each_console_srcu(c) {
   592			short flags = console_srcu_read_flags(c);
   593	
   594			if (!console_is_usable(c, flags, true))
   595				continue;
   596			if (c == dbg_io_ops->cons)
   597				continue;
   598	
   599			if (flags & CON_NBCON) {
   600				struct nbcon_write_context wctxt = { };
   601	
   602				/*
   603				 * Do not continue if the console is NBCON and the context
   604				 * can't be acquired.
   605				 */
   606				if (!nbcon_kdb_try_acquire(c, &wctxt))
   607					continue;
   608	
   609				nbcon_write_context_set_buf(&wctxt, (char *)msg, msg_len);
   610	
   611				c->write_atomic(c, &wctxt);
 > 612				nbcon_kdb_release(&wctxt);
   613			} else {
   614				/*
   615				 * Set oops_in_progress to encourage the console drivers to
   616				 * disregard their internal spin locks: in the current calling
   617				 * context the risk of deadlock is a bigger problem than risks
   618				 * due to re-entering the console driver. We operate directly on
   619				 * oops_in_progress rather than using bust_spinlocks() because
   620				 * the calls bust_spinlocks() makes on exit are not appropriate
   621				 * for this calling context.
   622				 */
   623				++oops_in_progress;
   624				c->write(c, msg, msg_len);
   625				--oops_in_progress;
   626			}
   627			touch_nmi_watchdog();
   628		}
   629		console_srcu_read_unlock(cookie);
   630	}
   631	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki