Re: [PATCH v5] mm: slub: move sysfs slab alloc/free interfaces to debugfs
From: Dan Carpenter
Date: Fri May 07 2021 - 01:27:11 EST
Hi Faiyaz,
url: https://github.com/0day-ci/linux/commits/Faiyaz-Mohammed/mm-slub-move-sysfs-slab-alloc-free-interfaces-to-debugfs/20210506-182420
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 8404c9fbc84b741f66cff7d4934a25dd2c344452
config: i386-randconfig-m021-20210506 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
smatch warnings:
mm/slub.c:5891 slab_debugfs_start() warn: possible memory leak of 'spos'
vim +/spos +5891 mm/slub.c
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5877 static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos)
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5878 {
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5879 struct kmem_cache_node *n;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5880 struct kmem_cache *s;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5881 enum track_item alloc;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5882 int node;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5883 loff_t *spos = kmalloc(sizeof(loff_t), GFP_KERNEL);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Generally avoid putting functions which can fail in the declaration
block. Allocations inside the declaration block are a tiny percent of
declarations over all but they are an outsize source of static checker
bugs.
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5884
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5885 s = seq->file->f_inode->i_private;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5886
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5887 if (!spos)
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5888 return NULL;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5889
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5890 if (!(s->flags & SLAB_STORE_USER))
88e180b99466c1 Faiyaz Mohammed 2021-05-06 @5891 return ERR_PTR(-EOPNOTSUPP);
"spos" is leaked.
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5892
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5893 if (*ppos == 0) {
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5894
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5895 t.count = 0;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5896 t.max = 0;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5897 t.loc = NULL;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5898 if (strcmp(seq->file->f_path.dentry->d_name.name, "alloc_traces") == 0)
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5899 alloc = TRACK_ALLOC;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5900 else
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5901 alloc = TRACK_FREE;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5902
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5903 if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5904 GFP_KERNEL)) {
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5905 seq_puts(seq, "Out of memory\n");
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5906 return ERR_PTR(-ENOMEM);
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5907 }
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5908 /* Push back cpu slabs */
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5909 flush_all(s);
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5910
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5911 for_each_kmem_cache_node(s, node, n) {
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5912 unsigned long flags;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5913 struct page *page;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5914
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5915 if (!atomic_long_read(&n->nr_slabs))
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5916 continue;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5917
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5918 spin_lock_irqsave(&n->list_lock, flags);
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5919 list_for_each_entry(page, &n->partial, slab_list)
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5920 process_slab(&t, s, page, alloc);
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5921 list_for_each_entry(page, &n->full, slab_list)
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5922 process_slab(&t, s, page, alloc);
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5923 spin_unlock_irqrestore(&n->list_lock, flags);
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5924 }
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5925 }
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5926
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5927 if (*ppos < t.count) {
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5928 *spos = *ppos;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5929 return spos;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5930 }
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5931
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5932 kfree(spos);
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5933 return NULL;
88e180b99466c1 Faiyaz Mohammed 2021-05-06 5934 }
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0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx