Re: [PATCH] btrfs: implement ref_tracker for delayed_nodes

[kernel test robot <lkp@intel.com>]

Hi Leo,

kernel test robot noticed the following build errors:

[auto build test ERROR on kdave/for-next]
[also build test ERROR on linus/master v6.16-rc5 next-20250710]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Leo-Martins/btrfs-implement-ref_tracker-for-delayed_nodes/20250710-060640
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git for-next
patch link:    https://lore.kernel.org/r/fa19acf9dc38e93546183fc083c365cdb237e89b.1752098515.git.loemra.dev%40gmail.com
patch subject: [PATCH] btrfs: implement ref_tracker for delayed_nodes
config: m68k-allmodconfig (https://download.01.org/0day-ci/archive/20250711/202507111111.Eh3BAP7i-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250711/202507111111.Eh3BAP7i-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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202507111111.Eh3BAP7i-lkp@intel.com/

All errors (new ones prefixed by >>):

   lib/ref_tracker.c: In function 'ref_tracker_alloc':
>> lib/ref_tracker.c:209:22: error: implicit declaration of function 'stack_trace_save'; did you mean 'stack_depot_save'? [-Wimplicit-function-declaration]
     209 |         nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
         |                      ^~~~~~~~~~~~~~~~
         |                      stack_depot_save

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for REF_TRACKER
   Depends on [n]: STACKTRACE_SUPPORT
   Selected by [y]:
   - BTRFS_DELAYED_NODE_REF_TRACKER [=y] && BLOCK [=y] && BTRFS_DEBUG [=y]


vim +209 lib/ref_tracker.c

4e66934eaadc83 Eric Dumazet  2021-12-04  184  
4e66934eaadc83 Eric Dumazet  2021-12-04  185  int ref_tracker_alloc(struct ref_tracker_dir *dir,
4e66934eaadc83 Eric Dumazet  2021-12-04  186  		      struct ref_tracker **trackerp,
4e66934eaadc83 Eric Dumazet  2021-12-04  187  		      gfp_t gfp)
4e66934eaadc83 Eric Dumazet  2021-12-04  188  {
4e66934eaadc83 Eric Dumazet  2021-12-04  189  	unsigned long entries[REF_TRACKER_STACK_ENTRIES];
4e66934eaadc83 Eric Dumazet  2021-12-04  190  	struct ref_tracker *tracker;
4e66934eaadc83 Eric Dumazet  2021-12-04  191  	unsigned int nr_entries;
acd8f0e5d72741 Andrzej Hajda 2023-06-02  192  	gfp_t gfp_mask = gfp | __GFP_NOWARN;
4e66934eaadc83 Eric Dumazet  2021-12-04  193  	unsigned long flags;
4e66934eaadc83 Eric Dumazet  2021-12-04  194  
e3ececfe668fac Eric Dumazet  2022-02-04  195  	WARN_ON_ONCE(dir->dead);
e3ececfe668fac Eric Dumazet  2022-02-04  196  
8fd5522f44dcd7 Eric Dumazet  2022-02-04  197  	if (!trackerp) {
8fd5522f44dcd7 Eric Dumazet  2022-02-04  198  		refcount_inc(&dir->no_tracker);
8fd5522f44dcd7 Eric Dumazet  2022-02-04  199  		return 0;
8fd5522f44dcd7 Eric Dumazet  2022-02-04  200  	}
c12837d1bb3103 Eric Dumazet  2022-01-12  201  	if (gfp & __GFP_DIRECT_RECLAIM)
c12837d1bb3103 Eric Dumazet  2022-01-12  202  		gfp_mask |= __GFP_NOFAIL;
c12837d1bb3103 Eric Dumazet  2022-01-12  203  	*trackerp = tracker = kzalloc(sizeof(*tracker), gfp_mask);
4e66934eaadc83 Eric Dumazet  2021-12-04  204  	if (unlikely(!tracker)) {
4e66934eaadc83 Eric Dumazet  2021-12-04  205  		pr_err_once("memory allocation failure, unreliable refcount tracker.\n");
4e66934eaadc83 Eric Dumazet  2021-12-04  206  		refcount_inc(&dir->untracked);
4e66934eaadc83 Eric Dumazet  2021-12-04  207  		return -ENOMEM;
4e66934eaadc83 Eric Dumazet  2021-12-04  208  	}
4e66934eaadc83 Eric Dumazet  2021-12-04 @209  	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
4e66934eaadc83 Eric Dumazet  2021-12-04  210  	tracker->alloc_stack_handle = stack_depot_save(entries, nr_entries, gfp);
4e66934eaadc83 Eric Dumazet  2021-12-04  211  
4e66934eaadc83 Eric Dumazet  2021-12-04  212  	spin_lock_irqsave(&dir->lock, flags);
4e66934eaadc83 Eric Dumazet  2021-12-04  213  	list_add(&tracker->head, &dir->list);
4e66934eaadc83 Eric Dumazet  2021-12-04  214  	spin_unlock_irqrestore(&dir->lock, flags);
4e66934eaadc83 Eric Dumazet  2021-12-04  215  	return 0;
4e66934eaadc83 Eric Dumazet  2021-12-04  216  }
4e66934eaadc83 Eric Dumazet  2021-12-04  217  EXPORT_SYMBOL_GPL(ref_tracker_alloc);
4e66934eaadc83 Eric Dumazet  2021-12-04  218  

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