CVE-2021-47483

In the Linux kernel, the following vulnerability has been resolved: regmap:
Fix possible double-free in regcache_rbtree_exit() In
regcache_rbtree_insert_to_block(), when ‘present’ realloc failed, the ‘blk’
which is supposed to assign to ‘rbnode->block’ will be freed, so
‘rbnode->block’ points a freed memory, in the error handling path of
regcache_rbtree_init(), ‘rbnode->block’ will be freed again in
regcache_rbtree_exit(), KASAN will report double-free as follows: BUG:
KASAN: double-free or invalid-free in kfree+0xce/0x390 Call Trace:
slab_free_freelist_hook+0x10d/0x240 kfree+0xce/0x390
regcache_rbtree_exit+0x15d/0x1a0 regcache_rbtree_init+0x224/0x2c0
regcache_init+0x88d/0x1310 __regmap_init+0x3151/0x4a80
__devm_regmap_init+0x7d/0x100 madera_spi_probe+0x10f/0x333 [madera_spi]
spi_probe+0x183/0x210 really_probe+0x285/0xc30 To fix this, moving up the
assignment of rbnode->block to immediately after the reallocation has
succeeded so that the data structure stays valid even if the second
reallocation fails.