diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h index dccbeb25f701..6032eea2539a 100644 --- a/include/linux/inetdevice.h +++ b/include/linux/inetdevice.h @@ -293,6 +293,11 @@ static inline void in_dev_put(struct in_device *idev) #define __in_dev_put(idev) refcount_dec(&(idev)->refcnt) #define in_dev_hold(idev) refcount_inc(&(idev)->refcnt) +static inline bool in_dev_hold_safe(struct in_device *idev) +{ + return refcount_inc_not_zero(&idev->refcnt); +} + #endif /* __KERNEL__ */ static __inline__ __be32 inet_make_mask(int logmask) diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index d520ea4f6d14..3a1cb2a827f3 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -248,16 +248,20 @@ static void igmp_gq_start_timer(struct in_device *in_dev) return; in_dev->mr_gq_running = 1; - if (!mod_timer(&in_dev->mr_gq_timer, exp)) - in_dev_hold(in_dev); + if (in_dev_hold_safe(in_dev)) { + if (mod_timer(&in_dev->mr_gq_timer, exp)) + in_dev_put(in_dev); + } } static void igmp_ifc_start_timer(struct in_device *in_dev, int delay) { - int tv = get_random_u32_below(delay); + if (in_dev_hold_safe(in_dev)) { + int tv = get_random_u32_below(delay); - if (!mod_timer(&in_dev->mr_ifc_timer, jiffies+tv+2)) - in_dev_hold(in_dev); + if (mod_timer(&in_dev->mr_ifc_timer, jiffies + tv + 2)) + in_dev_put(in_dev); + } } static void igmp_mod_timer(struct ip_mc_list *im, int max_delay)