diff options
authorYang Yingliang <>2021-10-12 10:37:35 +0800
committerGreg Kroah-Hartman <>2021-11-02 17:38:12 +0100
commite72dce9afbdbfa70d9b44f5908a50ff6c4858999 (patch)
parent1ee34b2e09c21efdf8e9f96610f6a7b8fc458064 (diff)
regmap: Fix possible double-free in regcache_rbtree_exit()
commit 55e6d8037805b3400096d621091dfbf713f97e83 upstream. 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. Reported-by: Hulk Robot <> Fixes: 3f4ff561bc88b ("regmap: rbtree: Make cache_present bitmap per node") Signed-off-by: Yang Yingliang <> Link: Signed-off-by: Mark Brown <> Signed-off-by: Greg Kroah-Hartman <>
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/base/regmap/regcache-rbtree.c b/drivers/base/regmap/regcache-rbtree.c
index 56486d92c4e7..f868dda30da0 100644
--- a/drivers/base/regmap/regcache-rbtree.c
+++ b/drivers/base/regmap/regcache-rbtree.c
@@ -296,14 +296,14 @@ static int regcache_rbtree_insert_to_block(struct regmap *map,
if (!blk)
return -ENOMEM;
+ rbnode->block = blk;
if (BITS_TO_LONGS(blklen) > BITS_TO_LONGS(rbnode->blklen)) {
present = krealloc(rbnode->cache_present,
BITS_TO_LONGS(blklen) * sizeof(*present),
- if (!present) {
- kfree(blk);
+ if (!present)
return -ENOMEM;
- }
memset(present + BITS_TO_LONGS(rbnode->blklen), 0,
(BITS_TO_LONGS(blklen) - BITS_TO_LONGS(rbnode->blklen))
@@ -320,7 +320,6 @@ static int regcache_rbtree_insert_to_block(struct regmap *map,
/* update the rbnode block, its size and the base register */
- rbnode->block = blk;
rbnode->blklen = blklen;
rbnode->base_reg = base_reg;
rbnode->cache_present = present;