From 197b3975f4b079f004b02786bfa985ec276f6112 Mon Sep 17 00:00:00 2001 From: Quentin Casasnovas Date: Wed, 12 Nov 2014 11:19:23 +0100 Subject: regmap: fix kernel hang on regmap_bulk_write with zero val_count. Fixes commit 2f06fa04cf35da5c24481da3ac84a2900d0b99c3 which was an incorrect backported version of commit d6b41cb06044a7d895db82bdd54f6e4219970510 upstream. If val_count is zero we return -EINVAL with map->lock_arg locked, which will deadlock the kernel next time we try to acquire this lock. This was introduced by f5942dd ("regmap: fix possible ZERO_SIZE_PTR pointer dereferencing error.") which improperly back-ported d6b41cb0. This issue was found during review of Ubuntu Trusty 3.13.0-40.68 kernel to prepare Ksplice rebootless updates. Fixes: f5942dd ("regmap: fix possible ZERO_SIZE_PTR pointer dereferencing error.") Signed-off-by: Quentin Casasnovas Signed-off-by: Greg Kroah-Hartman --- drivers/base/regmap/regmap.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index f6cff3be0ed7..2f9a3d8ecbbf 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -1557,8 +1557,10 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val, } else { void *wval; - if (!val_count) - return -EINVAL; + if (!val_count) { + ret = -EINVAL; + goto out; + } wval = kmemdup(val, val_count * val_bytes, GFP_KERNEL); if (!wval) { -- cgit v1.2.3