| Message ID | 20170819003655.64903-1-tracywwnj@gmail.com |
|---|---|
| State | Superseded, archived |
| Delegated to: | David Miller |
| Headers | show |
On Fri, Aug 18, 2017 at 05:36:55PM -0700, Wei Wang wrote: > From: Wei Wang <weiwan@google.com> > > We currently keep rt->rt6i_node pointing to the fib6_node for the route. > And some functions make use of this pointer to dereference the fib6_node > from rt structure, e.g. rt6_check(). However, as there is neither > refcount nor rcu taken when dereferencing rt->rt6i_node, it could > potentially cause crashes as rt->rt6i_node could be set to NULL by other > CPUs when doing a route deletion. > This patch introduces an rcu grace period before freeing fib6_node and > makes sure the functions that dereference it takes rcu_read_lock(). > > Note: there is no "Fixes" tag because this bug was there in a very > early stage. > > Signed-off-by: Wei Wang <weiwan@google.com> > Acked-by: Eric Dumazet <edumazet@google.com> Looks good. Thanks for the fixing it. Only have some nits comments. > --- > include/net/ip6_fib.h | 31 ++++++++++++++++++++++++++++++- > net/ipv6/ip6_fib.c | 20 ++++++++++++++++---- > net/ipv6/route.c | 14 +++++++++++--- > 3 files changed, 57 insertions(+), 8 deletions(-) > > diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h > index 71c1646298ae..5691faf6b495 100644 > --- a/include/net/ip6_fib.h > +++ b/include/net/ip6_fib.h > @@ -72,6 +72,7 @@ struct fib6_node { > __u16 fn_flags; > int fn_sernum; > struct rt6_info *rr_ptr; > + struct rcu_head rcu; > }; > > #ifndef CONFIG_IPV6_SUBTREES > @@ -171,13 +172,41 @@ static inline void rt6_update_expires(struct rt6_info *rt0, int timeout) > rt0->rt6i_flags |= RTF_EXPIRES; > } > > +/* Function to safely get fn->sernum for passed in rt > + * and store result in passed in cookie. > + * Return true if we can get cookie safely > + * Return false if not > + */ > +static inline bool rt6_get_cookie_safe(const struct rt6_info *rt, > + u32 *cookie) Looking at fib6_new_sernum(), fn_sernum should be >0. Would it further simplify the later changes if we do this instead?: static inline u32 rt6_get_cookie_safe(const struct rt6_info *rt) > +{ > + struct fib6_node *fn; > + bool status = false; > + > + rcu_read_lock(); > + fn = rcu_dereference(rt->rt6i_node); > + > + if (fn) { > + *cookie = fn->fn_sernum; > + status = true; > + } > + > + rcu_read_unlock(); > + return status; > + extra newline. > +} > + > static inline u32 rt6_get_cookie(const struct rt6_info *rt) > { > + u32 cookie = 0; > + > if (rt->rt6i_flags & RTF_PCPU || > (unlikely(!list_empty(&rt->rt6i_uncached)) && rt->dst.from)) > rt = (struct rt6_info *)(rt->dst.from); > > - return rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0; > + rt6_get_cookie_safe(rt, &cookie); > + > + return cookie; > } > > static inline void ip6_rt_put(struct rt6_info *rt) > diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c > index 549aacc3cb2c..a9821c230e4e 100644 > --- a/net/ipv6/ip6_fib.c > +++ b/net/ipv6/ip6_fib.c > @@ -149,11 +149,23 @@ static struct fib6_node *node_alloc(void) > return fn; > } > > -static void node_free(struct fib6_node *fn) > +static void node_free_immediate(struct fib6_node *fn) > +{ > + kmem_cache_free(fib6_node_kmem, fn); > +} > + > +static void node_free_rcu(struct rcu_head *head) > { > + struct fib6_node *fn = container_of(head, struct fib6_node, rcu); > + > kmem_cache_free(fib6_node_kmem, fn); > } > > +static void node_free(struct fib6_node *fn) > +{ > + call_rcu(&fn->rcu, node_free_rcu); > +} > + > void rt6_free_pcpu(struct rt6_info *non_pcpu_rt) > { > int cpu; > @@ -697,9 +709,9 @@ static struct fib6_node *fib6_add_1(struct fib6_node *root, > > if (!in || !ln) { > if (in) > - node_free(in); > + node_free_immediate(in); > if (ln) > - node_free(ln); > + node_free_immediate(ln); > return ERR_PTR(-ENOMEM); > } > > @@ -1138,7 +1150,7 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, > root, and then (in failure) stale node > in main tree. > */ > - node_free(sfn); > + node_free_immediate(sfn); > err = PTR_ERR(sn); > goto failure; > } > diff --git a/net/ipv6/route.c b/net/ipv6/route.c > index bec12ae3e6b7..4de2d793c4b8 100644 > --- a/net/ipv6/route.c > +++ b/net/ipv6/route.c > @@ -1289,7 +1289,9 @@ static void rt6_dst_from_metrics_check(struct rt6_info *rt) > > static struct dst_entry *rt6_check(struct rt6_info *rt, u32 cookie) > { > - if (!rt->rt6i_node || (rt->rt6i_node->fn_sernum != cookie)) > + u32 rt_cookie; > + > + if (!rt6_get_cookie_safe(rt, &rt_cookie) || rt_cookie != cookie) > return NULL; > > if (rt6_check_expired(rt)) > @@ -1357,8 +1359,14 @@ static void ip6_link_failure(struct sk_buff *skb) > if (rt->rt6i_flags & RTF_CACHE) { > if (dst_hold_safe(&rt->dst)) > ip6_del_rt(rt); > - } else if (rt->rt6i_node && (rt->rt6i_flags & RTF_DEFAULT)) { > - rt->rt6i_node->fn_sernum = -1; > + } else { > + struct fib6_node *fn; > + > + rcu_read_lock(); > + fn = rcu_dereference(rt->rt6i_node); > + if (fn && (rt->rt6i_flags & RTF_DEFAULT)) > + fn->fn_sernum = -1; > + rcu_read_unlock(); > } > } > } > -- > 2.14.1.480.gb18f417b89-goog >
Hi Martin, >> +/* Function to safely get fn->sernum for passed in rt >> + * and store result in passed in cookie. >> + * Return true if we can get cookie safely >> + * Return false if not >> + */ >> +static inline bool rt6_get_cookie_safe(const struct rt6_info *rt, >> + u32 *cookie) > Looking at fib6_new_sernum(), fn_sernum should be >0. > > Would it further simplify the later changes if we do this instead?: > static inline u32 rt6_get_cookie_safe(const struct rt6_info *rt) > I don't think rt6_check() will work properly if this function only returns fn_sernum. Because rt6_get_cookie() will return cookie as 0 if the node is already deleted. And socket will store 0 as its dst_cookie. And when ip6_dst_check() is called, rt6_check() calls rt6_get_cookie_safe() to get the current sernum in fib6_node and finds it is also 0, so it will say the dst is valid. But it is wrong. Basically, the return status of rt6_get_cookie_safe() indicates if the rt6i_node is NULL or not. And it needs to be checked in rt6_check(). >> +{ >> + struct fib6_node *fn; >> + bool status = false; >> + >> + rcu_read_lock(); >> + fn = rcu_dereference(rt->rt6i_node); >> + >> + if (fn) { >> + *cookie = fn->fn_sernum; >> + status = true; >> + } >> + >> + rcu_read_unlock(); >> + return status; >> + > extra newline. > Thanks. Will remove it in v2. Wei On Fri, Aug 18, 2017 at 7:20 PM, Martin KaFai Lau <kafai@fb.com> wrote: > On Fri, Aug 18, 2017 at 05:36:55PM -0700, Wei Wang wrote: >> From: Wei Wang <weiwan@google.com> >> >> We currently keep rt->rt6i_node pointing to the fib6_node for the route. >> And some functions make use of this pointer to dereference the fib6_node >> from rt structure, e.g. rt6_check(). However, as there is neither >> refcount nor rcu taken when dereferencing rt->rt6i_node, it could >> potentially cause crashes as rt->rt6i_node could be set to NULL by other >> CPUs when doing a route deletion. >> This patch introduces an rcu grace period before freeing fib6_node and >> makes sure the functions that dereference it takes rcu_read_lock(). >> >> Note: there is no "Fixes" tag because this bug was there in a very >> early stage. >> >> Signed-off-by: Wei Wang <weiwan@google.com> >> Acked-by: Eric Dumazet <edumazet@google.com> > Looks good. Thanks for the fixing it. > Only have some nits comments. > >> --- >> include/net/ip6_fib.h | 31 ++++++++++++++++++++++++++++++- >> net/ipv6/ip6_fib.c | 20 ++++++++++++++++---- >> net/ipv6/route.c | 14 +++++++++++--- >> 3 files changed, 57 insertions(+), 8 deletions(-) >> >> diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h >> index 71c1646298ae..5691faf6b495 100644 >> --- a/include/net/ip6_fib.h >> +++ b/include/net/ip6_fib.h >> @@ -72,6 +72,7 @@ struct fib6_node { >> __u16 fn_flags; >> int fn_sernum; >> struct rt6_info *rr_ptr; >> + struct rcu_head rcu; >> }; >> >> #ifndef CONFIG_IPV6_SUBTREES >> @@ -171,13 +172,41 @@ static inline void rt6_update_expires(struct rt6_info *rt0, int timeout) >> rt0->rt6i_flags |= RTF_EXPIRES; >> } >> >> +/* Function to safely get fn->sernum for passed in rt >> + * and store result in passed in cookie. >> + * Return true if we can get cookie safely >> + * Return false if not >> + */ >> +static inline bool rt6_get_cookie_safe(const struct rt6_info *rt, >> + u32 *cookie) > Looking at fib6_new_sernum(), fn_sernum should be >0. > > Would it further simplify the later changes if we do this instead?: > static inline u32 rt6_get_cookie_safe(const struct rt6_info *rt) > >> +{ >> + struct fib6_node *fn; >> + bool status = false; >> + >> + rcu_read_lock(); >> + fn = rcu_dereference(rt->rt6i_node); >> + >> + if (fn) { >> + *cookie = fn->fn_sernum; >> + status = true; >> + } >> + >> + rcu_read_unlock(); >> + return status; >> + > extra newline. > >> +} >> + >> static inline u32 rt6_get_cookie(const struct rt6_info *rt) >> { >> + u32 cookie = 0; >> + >> if (rt->rt6i_flags & RTF_PCPU || >> (unlikely(!list_empty(&rt->rt6i_uncached)) && rt->dst.from)) >> rt = (struct rt6_info *)(rt->dst.from); >> >> - return rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0; >> + rt6_get_cookie_safe(rt, &cookie); >> + >> + return cookie; >> } >> >> static inline void ip6_rt_put(struct rt6_info *rt) >> diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c >> index 549aacc3cb2c..a9821c230e4e 100644 >> --- a/net/ipv6/ip6_fib.c >> +++ b/net/ipv6/ip6_fib.c >> @@ -149,11 +149,23 @@ static struct fib6_node *node_alloc(void) >> return fn; >> } >> >> -static void node_free(struct fib6_node *fn) >> +static void node_free_immediate(struct fib6_node *fn) >> +{ >> + kmem_cache_free(fib6_node_kmem, fn); >> +} >> + >> +static void node_free_rcu(struct rcu_head *head) >> { >> + struct fib6_node *fn = container_of(head, struct fib6_node, rcu); >> + >> kmem_cache_free(fib6_node_kmem, fn); >> } >> >> +static void node_free(struct fib6_node *fn) >> +{ >> + call_rcu(&fn->rcu, node_free_rcu); >> +} >> + >> void rt6_free_pcpu(struct rt6_info *non_pcpu_rt) >> { >> int cpu; >> @@ -697,9 +709,9 @@ static struct fib6_node *fib6_add_1(struct fib6_node *root, >> >> if (!in || !ln) { >> if (in) >> - node_free(in); >> + node_free_immediate(in); >> if (ln) >> - node_free(ln); >> + node_free_immediate(ln); >> return ERR_PTR(-ENOMEM); >> } >> >> @@ -1138,7 +1150,7 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, >> root, and then (in failure) stale node >> in main tree. >> */ >> - node_free(sfn); >> + node_free_immediate(sfn); >> err = PTR_ERR(sn); >> goto failure; >> } >> diff --git a/net/ipv6/route.c b/net/ipv6/route.c >> index bec12ae3e6b7..4de2d793c4b8 100644 >> --- a/net/ipv6/route.c >> +++ b/net/ipv6/route.c >> @@ -1289,7 +1289,9 @@ static void rt6_dst_from_metrics_check(struct rt6_info *rt) >> >> static struct dst_entry *rt6_check(struct rt6_info *rt, u32 cookie) >> { >> - if (!rt->rt6i_node || (rt->rt6i_node->fn_sernum != cookie)) >> + u32 rt_cookie; >> + >> + if (!rt6_get_cookie_safe(rt, &rt_cookie) || rt_cookie != cookie) >> return NULL; >> >> if (rt6_check_expired(rt)) >> @@ -1357,8 +1359,14 @@ static void ip6_link_failure(struct sk_buff *skb) >> if (rt->rt6i_flags & RTF_CACHE) { >> if (dst_hold_safe(&rt->dst)) >> ip6_del_rt(rt); >> - } else if (rt->rt6i_node && (rt->rt6i_flags & RTF_DEFAULT)) { >> - rt->rt6i_node->fn_sernum = -1; >> + } else { >> + struct fib6_node *fn; >> + >> + rcu_read_lock(); >> + fn = rcu_dereference(rt->rt6i_node); >> + if (fn && (rt->rt6i_flags & RTF_DEFAULT)) >> + fn->fn_sernum = -1; >> + rcu_read_unlock(); >> } >> } >> } >> -- >> 2.14.1.480.gb18f417b89-goog >>
On Sat, Aug 19, 2017 at 09:51:52AM -0700, Wei Wang wrote: > Hi Martin, > > >> +/* Function to safely get fn->sernum for passed in rt > >> + * and store result in passed in cookie. > >> + * Return true if we can get cookie safely > >> + * Return false if not > >> + */ > >> +static inline bool rt6_get_cookie_safe(const struct rt6_info *rt, > >> + u32 *cookie) > > Looking at fib6_new_sernum(), fn_sernum should be >0. > > > > Would it further simplify the later changes if we do this instead?: > > static inline u32 rt6_get_cookie_safe(const struct rt6_info *rt) > > > > I don't think rt6_check() will work properly if this function only > returns fn_sernum. Because rt6_get_cookie() will return cookie as 0 if > the node is already deleted. And socket will store 0 as its > dst_cookie. And when ip6_dst_check() is called, rt6_check() calls > rt6_get_cookie_safe() to get the current sernum in fib6_node and finds > it is also 0, so it will say the dst is valid. But it is wrong. Thanks for the explanation. Can rt6_check() just return NULL if the passed in cookie is already invalid (i.e. 0)? It should have no need to call rt6_get_cookie_safe() if the passed in cookie is already invalid, or it is still needed? Instead of having another bool 'false', I was mostly thinking having one invalid state 'cookie 0' will be easier to read and code later. However, it is not curical. Lets get this fix in. > Basically, the return status of rt6_get_cookie_safe() indicates if the > rt6i_node is NULL or not. And it needs to be checked in rt6_check(). > > >> +{ > >> + struct fib6_node *fn; > >> + bool status = false; > >> + > >> + rcu_read_lock(); > >> + fn = rcu_dereference(rt->rt6i_node); > >> + > >> + if (fn) { > >> + *cookie = fn->fn_sernum; > >> + status = true; > >> + } > >> + > >> + rcu_read_unlock(); > >> + return status; > >> + > > extra newline. > > > > Thanks. Will remove it in v2. > > Wei > > > On Fri, Aug 18, 2017 at 7:20 PM, Martin KaFai Lau <kafai@fb.com> wrote: > > On Fri, Aug 18, 2017 at 05:36:55PM -0700, Wei Wang wrote: > >> From: Wei Wang <weiwan@google.com> > >> > >> We currently keep rt->rt6i_node pointing to the fib6_node for the route. > >> And some functions make use of this pointer to dereference the fib6_node > >> from rt structure, e.g. rt6_check(). However, as there is neither > >> refcount nor rcu taken when dereferencing rt->rt6i_node, it could > >> potentially cause crashes as rt->rt6i_node could be set to NULL by other > >> CPUs when doing a route deletion. > >> This patch introduces an rcu grace period before freeing fib6_node and > >> makes sure the functions that dereference it takes rcu_read_lock(). > >> > >> Note: there is no "Fixes" tag because this bug was there in a very > >> early stage. > >> > >> Signed-off-by: Wei Wang <weiwan@google.com> > >> Acked-by: Eric Dumazet <edumazet@google.com> > > Looks good. Thanks for the fixing it. > > Only have some nits comments. > > > >> --- > >> include/net/ip6_fib.h | 31 ++++++++++++++++++++++++++++++- > >> net/ipv6/ip6_fib.c | 20 ++++++++++++++++---- > >> net/ipv6/route.c | 14 +++++++++++--- > >> 3 files changed, 57 insertions(+), 8 deletions(-) > >> > >> diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h > >> index 71c1646298ae..5691faf6b495 100644 > >> --- a/include/net/ip6_fib.h > >> +++ b/include/net/ip6_fib.h > >> @@ -72,6 +72,7 @@ struct fib6_node { > >> __u16 fn_flags; > >> int fn_sernum; > >> struct rt6_info *rr_ptr; > >> + struct rcu_head rcu; > >> }; > >> > >> #ifndef CONFIG_IPV6_SUBTREES > >> @@ -171,13 +172,41 @@ static inline void rt6_update_expires(struct rt6_info *rt0, int timeout) > >> rt0->rt6i_flags |= RTF_EXPIRES; > >> } > >> > >> +/* Function to safely get fn->sernum for passed in rt > >> + * and store result in passed in cookie. > >> + * Return true if we can get cookie safely > >> + * Return false if not > >> + */ > >> +static inline bool rt6_get_cookie_safe(const struct rt6_info *rt, > >> + u32 *cookie) > > Looking at fib6_new_sernum(), fn_sernum should be >0. > > > > Would it further simplify the later changes if we do this instead?: > > static inline u32 rt6_get_cookie_safe(const struct rt6_info *rt) > > > >> +{ > >> + struct fib6_node *fn; > >> + bool status = false; > >> + > >> + rcu_read_lock(); > >> + fn = rcu_dereference(rt->rt6i_node); > >> + > >> + if (fn) { > >> + *cookie = fn->fn_sernum; > >> + status = true; > >> + } > >> + > >> + rcu_read_unlock(); > >> + return status; > >> + > > extra newline. > > > >> +} > >> + > >> static inline u32 rt6_get_cookie(const struct rt6_info *rt) > >> { > >> + u32 cookie = 0; > >> + > >> if (rt->rt6i_flags & RTF_PCPU || > >> (unlikely(!list_empty(&rt->rt6i_uncached)) && rt->dst.from)) > >> rt = (struct rt6_info *)(rt->dst.from); > >> > >> - return rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0; > >> + rt6_get_cookie_safe(rt, &cookie); > >> + > >> + return cookie; > >> } > >> > >> static inline void ip6_rt_put(struct rt6_info *rt) > >> diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c > >> index 549aacc3cb2c..a9821c230e4e 100644 > >> --- a/net/ipv6/ip6_fib.c > >> +++ b/net/ipv6/ip6_fib.c > >> @@ -149,11 +149,23 @@ static struct fib6_node *node_alloc(void) > >> return fn; > >> } > >> > >> -static void node_free(struct fib6_node *fn) > >> +static void node_free_immediate(struct fib6_node *fn) > >> +{ > >> + kmem_cache_free(fib6_node_kmem, fn); > >> +} > >> + > >> +static void node_free_rcu(struct rcu_head *head) > >> { > >> + struct fib6_node *fn = container_of(head, struct fib6_node, rcu); > >> + > >> kmem_cache_free(fib6_node_kmem, fn); > >> } > >> > >> +static void node_free(struct fib6_node *fn) > >> +{ > >> + call_rcu(&fn->rcu, node_free_rcu); > >> +} > >> + > >> void rt6_free_pcpu(struct rt6_info *non_pcpu_rt) > >> { > >> int cpu; > >> @@ -697,9 +709,9 @@ static struct fib6_node *fib6_add_1(struct fib6_node *root, > >> > >> if (!in || !ln) { > >> if (in) > >> - node_free(in); > >> + node_free_immediate(in); > >> if (ln) > >> - node_free(ln); > >> + node_free_immediate(ln); > >> return ERR_PTR(-ENOMEM); > >> } > >> > >> @@ -1138,7 +1150,7 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, > >> root, and then (in failure) stale node > >> in main tree. > >> */ > >> - node_free(sfn); > >> + node_free_immediate(sfn); > >> err = PTR_ERR(sn); > >> goto failure; > >> } > >> diff --git a/net/ipv6/route.c b/net/ipv6/route.c > >> index bec12ae3e6b7..4de2d793c4b8 100644 > >> --- a/net/ipv6/route.c > >> +++ b/net/ipv6/route.c > >> @@ -1289,7 +1289,9 @@ static void rt6_dst_from_metrics_check(struct rt6_info *rt) > >> > >> static struct dst_entry *rt6_check(struct rt6_info *rt, u32 cookie) > >> { > >> - if (!rt->rt6i_node || (rt->rt6i_node->fn_sernum != cookie)) > >> + u32 rt_cookie; > >> + > >> + if (!rt6_get_cookie_safe(rt, &rt_cookie) || rt_cookie != cookie) > >> return NULL; > >> > >> if (rt6_check_expired(rt)) > >> @@ -1357,8 +1359,14 @@ static void ip6_link_failure(struct sk_buff *skb) > >> if (rt->rt6i_flags & RTF_CACHE) { > >> if (dst_hold_safe(&rt->dst)) > >> ip6_del_rt(rt); > >> - } else if (rt->rt6i_node && (rt->rt6i_flags & RTF_DEFAULT)) { > >> - rt->rt6i_node->fn_sernum = -1; > >> + } else { > >> + struct fib6_node *fn; > >> + > >> + rcu_read_lock(); > >> + fn = rcu_dereference(rt->rt6i_node); > >> + if (fn && (rt->rt6i_flags & RTF_DEFAULT)) > >> + fn->fn_sernum = -1; > >> + rcu_read_unlock(); > >> } > >> } > >> } > >> -- > >> 2.14.1.480.gb18f417b89-goog > >>
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h index 71c1646298ae..5691faf6b495 100644 --- a/include/net/ip6_fib.h +++ b/include/net/ip6_fib.h @@ -72,6 +72,7 @@ struct fib6_node { __u16 fn_flags; int fn_sernum; struct rt6_info *rr_ptr; + struct rcu_head rcu; }; #ifndef CONFIG_IPV6_SUBTREES @@ -171,13 +172,41 @@ static inline void rt6_update_expires(struct rt6_info *rt0, int timeout) rt0->rt6i_flags |= RTF_EXPIRES; } +/* Function to safely get fn->sernum for passed in rt + * and store result in passed in cookie. + * Return true if we can get cookie safely + * Return false if not + */ +static inline bool rt6_get_cookie_safe(const struct rt6_info *rt, + u32 *cookie) +{ + struct fib6_node *fn; + bool status = false; + + rcu_read_lock(); + fn = rcu_dereference(rt->rt6i_node); + + if (fn) { + *cookie = fn->fn_sernum; + status = true; + } + + rcu_read_unlock(); + return status; + +} + static inline u32 rt6_get_cookie(const struct rt6_info *rt) { + u32 cookie = 0; + if (rt->rt6i_flags & RTF_PCPU || (unlikely(!list_empty(&rt->rt6i_uncached)) && rt->dst.from)) rt = (struct rt6_info *)(rt->dst.from); - return rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0; + rt6_get_cookie_safe(rt, &cookie); + + return cookie; } static inline void ip6_rt_put(struct rt6_info *rt) diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 549aacc3cb2c..a9821c230e4e 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -149,11 +149,23 @@ static struct fib6_node *node_alloc(void) return fn; } -static void node_free(struct fib6_node *fn) +static void node_free_immediate(struct fib6_node *fn) +{ + kmem_cache_free(fib6_node_kmem, fn); +} + +static void node_free_rcu(struct rcu_head *head) { + struct fib6_node *fn = container_of(head, struct fib6_node, rcu); + kmem_cache_free(fib6_node_kmem, fn); } +static void node_free(struct fib6_node *fn) +{ + call_rcu(&fn->rcu, node_free_rcu); +} + void rt6_free_pcpu(struct rt6_info *non_pcpu_rt) { int cpu; @@ -697,9 +709,9 @@ static struct fib6_node *fib6_add_1(struct fib6_node *root, if (!in || !ln) { if (in) - node_free(in); + node_free_immediate(in); if (ln) - node_free(ln); + node_free_immediate(ln); return ERR_PTR(-ENOMEM); } @@ -1138,7 +1150,7 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, root, and then (in failure) stale node in main tree. */ - node_free(sfn); + node_free_immediate(sfn); err = PTR_ERR(sn); goto failure; } diff --git a/net/ipv6/route.c b/net/ipv6/route.c index bec12ae3e6b7..4de2d793c4b8 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1289,7 +1289,9 @@ static void rt6_dst_from_metrics_check(struct rt6_info *rt) static struct dst_entry *rt6_check(struct rt6_info *rt, u32 cookie) { - if (!rt->rt6i_node || (rt->rt6i_node->fn_sernum != cookie)) + u32 rt_cookie; + + if (!rt6_get_cookie_safe(rt, &rt_cookie) || rt_cookie != cookie) return NULL; if (rt6_check_expired(rt)) @@ -1357,8 +1359,14 @@ static void ip6_link_failure(struct sk_buff *skb) if (rt->rt6i_flags & RTF_CACHE) { if (dst_hold_safe(&rt->dst)) ip6_del_rt(rt); - } else if (rt->rt6i_node && (rt->rt6i_flags & RTF_DEFAULT)) { - rt->rt6i_node->fn_sernum = -1; + } else { + struct fib6_node *fn; + + rcu_read_lock(); + fn = rcu_dereference(rt->rt6i_node); + if (fn && (rt->rt6i_flags & RTF_DEFAULT)) + fn->fn_sernum = -1; + rcu_read_unlock(); } } }