From a7a2830c5cf50217e38ffbc6797e36bc15bb4f1c Mon Sep 17 00:00:00 2001 From: Quentin Casasnovas <quentin.casasnovas@oracle.com> Date: Wed, 12 Nov 2014 11:19:23 +0100 Subject: [PATCH] regmap: fix kernel hang on regmap_bulk_write with zero val_count. 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. In 3.12, this was introduced by a0b8d8d906d267987d507138003048c5fdf774 ("regmap: fix possible ZERO_SIZE_PTR pointer dereferencing error.") which improperly back-ported d6b41cb06044a7d895db82bdd54f6e4219970510. 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 <quentin.casasnovas@oracle.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> --- drivers/base/regmap/regmap.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index 7a58be457eb52d..9f799018765378 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -1403,8 +1403,10 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val, if (val_bytes == 1) { wval = (void *)val; } else { - if (!val_count) - return -EINVAL; + if (!val_count) { + ret = -EINVAL; + goto out; + } wval = kmemdup(val, val_count * val_bytes, GFP_KERNEL); if (!wval) {