From: Taehee Yoo ap420073@gmail.com
[ Upstream commit a13f814a67b12a2f29d1decf4b4f4e700658a517 ]
The nft_set_gc_batch_check() checks whether gc buffer is full. If gc buffer is full, gc buffer is released by the nft_set_gc_batch_complete() internally. In case of rbtree, the rb_erase() should be called before calling the nft_set_gc_batch_complete(). therefore the rb_erase() should be called before calling the nft_set_gc_batch_check() too.
test commands: table ip filter { set set1 { type ipv4_addr; flags interval, timeout; gc-interval 10s; timeout 1s; elements = { 1-2, 3-4, 5-6, ... 10000-10001, } } } %nft -f test.nft
splat looks like: [ 430.273885] kasan: GPF could be caused by NULL-ptr deref or user memory access [ 430.282158] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI [ 430.283116] CPU: 1 PID: 190 Comm: kworker/1:2 Tainted: G B 4.18.0+ #7 [ 430.283116] Workqueue: events_power_efficient nft_rbtree_gc [nf_tables_set] [ 430.313559] RIP: 0010:rb_next+0x81/0x130 [ 430.313559] Code: 08 49 bd 00 00 00 00 00 fc ff df 48 bb 00 00 00 00 00 fc ff df 48 85 c0 75 05 eb 58 48 89 d4 [ 430.313559] RSP: 0018:ffff88010cdb7680 EFLAGS: 00010207 [ 430.313559] RAX: 0000000000b84854 RBX: dffffc0000000000 RCX: ffffffff83f01973 [ 430.313559] RDX: 000000000017090c RSI: 0000000000000008 RDI: 0000000000b84864 [ 430.313559] RBP: ffff8801060d4588 R08: fffffbfff09bc349 R09: fffffbfff09bc349 [ 430.313559] R10: 0000000000000001 R11: fffffbfff09bc348 R12: ffff880100f081a8 [ 430.313559] R13: dffffc0000000000 R14: ffff880100ff8688 R15: dffffc0000000000 [ 430.313559] FS: 0000000000000000(0000) GS:ffff88011b400000(0000) knlGS:0000000000000000 [ 430.313559] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 430.313559] CR2: 0000000001551008 CR3: 000000005dc16000 CR4: 00000000001006e0 [ 430.313559] Call Trace: [ 430.313559] nft_rbtree_gc+0x112/0x5c0 [nf_tables_set] [ 430.313559] process_one_work+0xc13/0x1ec0 [ 430.313559] ? _raw_spin_unlock_irq+0x29/0x40 [ 430.313559] ? pwq_dec_nr_in_flight+0x3c0/0x3c0 [ 430.313559] ? set_load_weight+0x270/0x270 [ 430.313559] ? __switch_to_asm+0x34/0x70 [ 430.313559] ? __switch_to_asm+0x40/0x70 [ 430.313559] ? __switch_to_asm+0x34/0x70 [ 430.313559] ? __switch_to_asm+0x34/0x70 [ 430.313559] ? __switch_to_asm+0x40/0x70 [ 430.313559] ? __switch_to_asm+0x34/0x70 [ 430.313559] ? __switch_to_asm+0x40/0x70 [ 430.313559] ? __switch_to_asm+0x34/0x70 [ 430.313559] ? __switch_to_asm+0x34/0x70 [ 430.313559] ? __switch_to_asm+0x40/0x70 [ 430.313559] ? __switch_to_asm+0x34/0x70 [ 430.313559] ? __schedule+0x6d3/0x1f50 [ 430.313559] ? find_held_lock+0x39/0x1c0 [ 430.313559] ? __sched_text_start+0x8/0x8 [ 430.313559] ? cyc2ns_read_end+0x10/0x10 [ 430.313559] ? save_trace+0x300/0x300 [ 430.313559] ? sched_clock_local+0xd4/0x140 [ 430.313559] ? find_held_lock+0x39/0x1c0 [ 430.313559] ? worker_thread+0x353/0x1120 [ 430.313559] ? worker_thread+0x353/0x1120 [ 430.313559] ? lock_contended+0xe70/0xe70 [ 430.313559] ? __lock_acquire+0x4500/0x4500 [ 430.535635] ? do_raw_spin_unlock+0xa5/0x330 [ 430.535635] ? do_raw_spin_trylock+0x101/0x1a0 [ 430.535635] ? do_raw_spin_lock+0x1f0/0x1f0 [ 430.535635] ? _raw_spin_lock_irq+0x10/0x70 [ 430.535635] worker_thread+0x15d/0x1120 [ ... ]
Fixes: 8d8540c4f5e0 ("netfilter: nft_set_rbtree: add timeout support") Signed-off-by: Taehee Yoo ap420073@gmail.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nft_set_rbtree.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-)
diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c index 9873d734b494..8ad78b82c8e2 100644 --- a/net/netfilter/nft_set_rbtree.c +++ b/net/netfilter/nft_set_rbtree.c @@ -355,12 +355,11 @@ static void nft_rbtree_walk(const struct nft_ctx *ctx,
static void nft_rbtree_gc(struct work_struct *work) { + struct nft_rbtree_elem *rbe, *rbe_end = NULL, *rbe_prev = NULL; struct nft_set_gc_batch *gcb = NULL; - struct rb_node *node, *prev = NULL; - struct nft_rbtree_elem *rbe; struct nft_rbtree *priv; + struct rb_node *node; struct nft_set *set; - int i;
priv = container_of(work, struct nft_rbtree, gc_work.work); set = nft_set_container_of(priv); @@ -371,7 +370,7 @@ static void nft_rbtree_gc(struct work_struct *work) rbe = rb_entry(node, struct nft_rbtree_elem, node);
if (nft_rbtree_interval_end(rbe)) { - prev = node; + rbe_end = rbe; continue; } if (!nft_set_elem_expired(&rbe->ext)) @@ -379,29 +378,30 @@ static void nft_rbtree_gc(struct work_struct *work) if (nft_set_elem_mark_busy(&rbe->ext)) continue;
+ if (rbe_prev) { + rb_erase(&rbe_prev->node, &priv->root); + rbe_prev = NULL; + } gcb = nft_set_gc_batch_check(set, gcb, GFP_ATOMIC); if (!gcb) break;
atomic_dec(&set->nelems); nft_set_gc_batch_add(gcb, rbe); + rbe_prev = rbe;
- if (prev) { - rbe = rb_entry(prev, struct nft_rbtree_elem, node); + if (rbe_end) { atomic_dec(&set->nelems); - nft_set_gc_batch_add(gcb, rbe); - prev = NULL; + nft_set_gc_batch_add(gcb, rbe_end); + rb_erase(&rbe_end->node, &priv->root); + rbe_end = NULL; } node = rb_next(node); if (!node) break; } - if (gcb) { - for (i = 0; i < gcb->head.cnt; i++) { - rbe = gcb->elems[i]; - rb_erase(&rbe->node, &priv->root); - } - } + if (rbe_prev) + rb_erase(&rbe_prev->node, &priv->root); write_seqcount_end(&priv->count); write_unlock_bh(&priv->lock);