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net: esp: fix bad handling of pages from page_pool
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[ Upstream commit c319882 ]

When the skb is reorganized during esp_output (!esp->inline), the pages
coming from the original skb fragments are supposed to be released back
to the system through put_page. But if the skb fragment pages are
originating from a page_pool, calling put_page on them will trigger a
page_pool leak which will eventually result in a crash.

This leak can be easily observed when using CONFIG_DEBUG_VM and doing
ipsec + gre (non offloaded) forwarding:

  BUG: Bad page state in process ksoftirqd/16  pfn:1451b6
  page:00000000de2b8d32 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1451b6000 pfn:0x1451b6
  flags: 0x200000000000000(node=0|zone=2)
  page_type: 0xffffffff()
  raw: 0200000000000000 dead000000000040 ffff88810d23c000 0000000000000000
  raw: 00000001451b6000 0000000000000001 00000000ffffffff 0000000000000000
  page dumped because: page_pool leak
  Modules linked in: ip_gre gre mlx5_ib mlx5_core xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat nf_nat xt_addrtype br_netfilter rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm ib_uverbs ib_core overlay zram zsmalloc fuse [last unloaded: mlx5_core]
  CPU: 16 PID: 96 Comm: ksoftirqd/16 Not tainted 6.8.0-rc4+ #22
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
  Call Trace:
   <TASK>
   dump_stack_lvl+0x36/0x50
   bad_page+0x70/0xf0
   free_unref_page_prepare+0x27a/0x460
   free_unref_page+0x38/0x120
   esp_ssg_unref.isra.0+0x15f/0x200
   esp_output_tail+0x66d/0x780
   esp_xmit+0x2c5/0x360
   validate_xmit_xfrm+0x313/0x370
   ? validate_xmit_skb+0x1d/0x330
   validate_xmit_skb_list+0x4c/0x70
   sch_direct_xmit+0x23e/0x350
   __dev_queue_xmit+0x337/0xba0
   ? nf_hook_slow+0x3f/0xd0
   ip_finish_output2+0x25e/0x580
   iptunnel_xmit+0x19b/0x240
   ip_tunnel_xmit+0x5fb/0xb60
   ipgre_xmit+0x14d/0x280 [ip_gre]
   dev_hard_start_xmit+0xc3/0x1c0
   __dev_queue_xmit+0x208/0xba0
   ? nf_hook_slow+0x3f/0xd0
   ip_finish_output2+0x1ca/0x580
   ip_sublist_rcv_finish+0x32/0x40
   ip_sublist_rcv+0x1b2/0x1f0
   ? ip_rcv_finish_core.constprop.0+0x460/0x460
   ip_list_rcv+0x103/0x130
   __netif_receive_skb_list_core+0x181/0x1e0
   netif_receive_skb_list_internal+0x1b3/0x2c0
   napi_gro_receive+0xc8/0x200
   gro_cell_poll+0x52/0x90
   __napi_poll+0x25/0x1a0
   net_rx_action+0x28e/0x300
   __do_softirq+0xc3/0x276
   ? sort_range+0x20/0x20
   run_ksoftirqd+0x1e/0x30
   smpboot_thread_fn+0xa6/0x130
   kthread+0xcd/0x100
   ? kthread_complete_and_exit+0x20/0x20
   ret_from_fork+0x31/0x50
   ? kthread_complete_and_exit+0x20/0x20
   ret_from_fork_asm+0x11/0x20
   </TASK>

The suggested fix is to introduce a new wrapper (skb_page_unref) that
covers page refcounting for page_pool pages as well.

Cc: [email protected]
Fixes: 6a5bcd8 ("page_pool: Allow drivers to hint on SKB recycling")
Reported-and-tested-by: Anatoli N.Chechelnickiy <[email protected]>
Reported-by: Ian Kumlien <[email protected]>
Link: https://lore.kernel.org/netdev/CAA85sZvvHtrpTQRqdaOx6gd55zPAVsqMYk_Lwh4Md5knTq7AyA@mail.gmail.com
Signed-off-by: Dragos Tatulea <[email protected]>
Reviewed-by: Mina Almasry <[email protected]>
Reviewed-by: Jakub Kicinski <[email protected]>
Acked-by: Ilias Apalodimas <[email protected]>
Signed-off-by: Steffen Klassert <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
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@dtatulea @gregkh
dtatulea authored and gregkh committed Apr 3, 2024
1 parent d0caabe commit 8291b4e
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Showing 3 changed files with 18 additions and 8 deletions.
10 changes: 10 additions & 0 deletions include/linux/skbuff.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3438,6 +3438,16 @@ static inline void skb_frag_ref(struct sk_buff *skb, int f)

bool napi_pp_put_page(struct page *page, bool napi_safe);

static inline void
skb_page_unref(const struct sk_buff *skb, struct page *page, bool napi_safe)
{
#ifdef CONFIG_PAGE_POOL
if (skb->pp_recycle && napi_pp_put_page(page, napi_safe))
return;
#endif
put_page(page);
}

static inline void
napi_frag_unref(skb_frag_t *frag, bool recycle, bool napi_safe)
{
Expand Down
8 changes: 4 additions & 4 deletions net/ipv4/esp4.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -95,7 +95,7 @@ static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
__alignof__(struct scatterlist));
}

static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb)
{
struct crypto_aead *aead = x->data;
int extralen = 0;
Expand All @@ -114,7 +114,7 @@ static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
*/
if (req->src != req->dst)
for (sg = sg_next(req->src); sg; sg = sg_next(sg))
put_page(sg_page(sg));
skb_page_unref(skb, sg_page(sg), false);
}

#ifdef CONFIG_INET_ESPINTCP
Expand Down Expand Up @@ -260,7 +260,7 @@ static void esp_output_done(void *data, int err)
}

tmp = ESP_SKB_CB(skb)->tmp;
esp_ssg_unref(x, tmp);
esp_ssg_unref(x, tmp, skb);
kfree(tmp);

if (xo && (xo->flags & XFRM_DEV_RESUME)) {
Expand Down Expand Up @@ -639,7 +639,7 @@ int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *
}

if (sg != dsg)
esp_ssg_unref(x, tmp);
esp_ssg_unref(x, tmp, skb);

if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
err = esp_output_tail_tcp(x, skb);
Expand Down
8 changes: 4 additions & 4 deletions net/ipv6/esp6.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -112,7 +112,7 @@ static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
__alignof__(struct scatterlist));
}

static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb)
{
struct crypto_aead *aead = x->data;
int extralen = 0;
Expand All @@ -131,7 +131,7 @@ static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
*/
if (req->src != req->dst)
for (sg = sg_next(req->src); sg; sg = sg_next(sg))
put_page(sg_page(sg));
skb_page_unref(skb, sg_page(sg), false);
}

#ifdef CONFIG_INET6_ESPINTCP
Expand Down Expand Up @@ -294,7 +294,7 @@ static void esp_output_done(void *data, int err)
}

tmp = ESP_SKB_CB(skb)->tmp;
esp_ssg_unref(x, tmp);
esp_ssg_unref(x, tmp, skb);
kfree(tmp);

esp_output_encap_csum(skb);
Expand Down Expand Up @@ -677,7 +677,7 @@ int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info
}

if (sg != dsg)
esp_ssg_unref(x, tmp);
esp_ssg_unref(x, tmp, skb);

if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
err = esp_output_tail_tcp(x, skb);
Expand Down

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