diff options
Diffstat (limited to 'debian/patches-rt/0233-net-core-protect-users-of-napi_alloc_cache-against-r.patch')
| -rw-r--r-- | debian/patches-rt/0233-net-core-protect-users-of-napi_alloc_cache-against-r.patch | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/debian/patches-rt/0233-net-core-protect-users-of-napi_alloc_cache-against-r.patch b/debian/patches-rt/0233-net-core-protect-users-of-napi_alloc_cache-against-r.patch new file mode 100644 index 000000000..58878036d --- /dev/null +++ b/debian/patches-rt/0233-net-core-protect-users-of-napi_alloc_cache-against-r.patch @@ -0,0 +1,115 @@ +From e8e3e8f9d02d605ac0820c51015b248d4c4a0873 Mon Sep 17 00:00:00 2001 +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Fri, 15 Jan 2016 16:33:34 +0100 +Subject: [PATCH 233/347] net/core: protect users of napi_alloc_cache against + reentrance +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +On -RT the code running in BH can not be moved to another CPU so CPU +local variable remain local. However the code can be preempted +and another task may enter BH accessing the same CPU using the same +napi_alloc_cache variable. +This patch ensures that each user of napi_alloc_cache uses a local lock. + +Cc: stable-rt@vger.kernel.org +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + net/core/skbuff.c | 23 ++++++++++++++++++----- + 1 file changed, 18 insertions(+), 5 deletions(-) + +diff --git a/net/core/skbuff.c b/net/core/skbuff.c +index 0696d3cb809d..58f78205585c 100644 +--- a/net/core/skbuff.c ++++ b/net/core/skbuff.c +@@ -332,6 +332,7 @@ struct napi_alloc_cache { + static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache); + static DEFINE_PER_CPU(struct napi_alloc_cache, napi_alloc_cache); + static DEFINE_LOCAL_IRQ_LOCK(netdev_alloc_lock); ++static DEFINE_LOCAL_IRQ_LOCK(napi_alloc_cache_lock); + + static void *__netdev_alloc_frag(unsigned int fragsz, gfp_t gfp_mask) + { +@@ -363,9 +364,13 @@ EXPORT_SYMBOL(netdev_alloc_frag); + + static void *__napi_alloc_frag(unsigned int fragsz, gfp_t gfp_mask) + { +- struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); ++ struct napi_alloc_cache *nc; ++ void *data; + +- return page_frag_alloc(&nc->page, fragsz, gfp_mask); ++ nc = &get_locked_var(napi_alloc_cache_lock, napi_alloc_cache); ++ data = page_frag_alloc(&nc->page, fragsz, gfp_mask); ++ put_locked_var(napi_alloc_cache_lock, napi_alloc_cache); ++ return data; + } + + void *napi_alloc_frag(unsigned int fragsz) +@@ -468,6 +473,7 @@ struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len, + struct napi_alloc_cache *nc; + struct sk_buff *skb; + void *data; ++ bool pfmemalloc; + + len += NET_SKB_PAD + NET_IP_ALIGN; + +@@ -490,7 +496,10 @@ struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len, + if (sk_memalloc_socks()) + gfp_mask |= __GFP_MEMALLOC; + ++ nc = &get_locked_var(napi_alloc_cache_lock, napi_alloc_cache); + data = page_frag_alloc(&nc->page, len, gfp_mask); ++ pfmemalloc = nc->page.pfmemalloc; ++ put_locked_var(napi_alloc_cache_lock, napi_alloc_cache); + if (unlikely(!data)) + return NULL; + +@@ -501,7 +510,7 @@ struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len, + } + + /* use OR instead of assignment to avoid clearing of bits in mask */ +- if (nc->page.pfmemalloc) ++ if (pfmemalloc) + skb->pfmemalloc = 1; + skb->head_frag = 1; + +@@ -733,23 +742,26 @@ void __consume_stateless_skb(struct sk_buff *skb) + + void __kfree_skb_flush(void) + { +- struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); ++ struct napi_alloc_cache *nc; + ++ nc = &get_locked_var(napi_alloc_cache_lock, napi_alloc_cache); + /* flush skb_cache if containing objects */ + if (nc->skb_count) { + kmem_cache_free_bulk(skbuff_head_cache, nc->skb_count, + nc->skb_cache); + nc->skb_count = 0; + } ++ put_locked_var(napi_alloc_cache_lock, napi_alloc_cache); + } + + static inline void _kfree_skb_defer(struct sk_buff *skb) + { +- struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); ++ struct napi_alloc_cache *nc; + + /* drop skb->head and call any destructors for packet */ + skb_release_all(skb); + ++ nc = &get_locked_var(napi_alloc_cache_lock, napi_alloc_cache); + /* record skb to CPU local list */ + nc->skb_cache[nc->skb_count++] = skb; + +@@ -764,6 +776,7 @@ static inline void _kfree_skb_defer(struct sk_buff *skb) + nc->skb_cache); + nc->skb_count = 0; + } ++ put_locked_var(napi_alloc_cache_lock, napi_alloc_cache); + } + void __kfree_skb_defer(struct sk_buff *skb) + { +-- +2.36.1 + |