* Re: [PATCH net] net: tun: Fix memory leaks of napi_get_frags
2022-11-02 9:30 [PATCH net] net: tun: Fix memory leaks of napi_get_frags Wang Yufen
@ 2022-11-02 9:13 ` wangyufen
0 siblings, 0 replies; 2+ messages in thread
From: wangyufen @ 2022-11-02 9:13 UTC (permalink / raw)
To: netdev, bpf; +Cc: davem, edumazet, kuba, pabeni, peterpenkov96
Ignore, will resend later
在 2022/11/2 17:30, Wang Yufen 写道:
> kmemleak reports after running test_progs:
>
> unreferenced object 0xffff8881b1672dc0 (size 232):
> comm "test_progs", pid 394388, jiffies 4354712116 (age 841.975s)
> hex dump (first 32 bytes):
> e0 84 d7 a8 81 88 ff ff 80 2c 67 b1 81 88 ff ff .........,g.....
> 00 40 c5 9b 81 88 ff ff 00 00 00 00 00 00 00 00 .@..............
> backtrace:
> [<00000000c8f01748>] napi_skb_cache_get+0xd4/0x150
> [<0000000041c7fc09>] __napi_build_skb+0x15/0x50
> [<00000000431c7079>] __napi_alloc_skb+0x26e/0x540
> [<000000003ecfa30e>] napi_get_frags+0x59/0x140
> [<0000000099b2199e>] tun_get_user+0x183d/0x3bb0 [tun]
> [<000000008a5adef0>] tun_chr_write_iter+0xc0/0x1b1 [tun]
> [<0000000049993ff4>] do_iter_readv_writev+0x19f/0x320
> [<000000008f338ea2>] do_iter_write+0x135/0x630
> [<000000008a3377a4>] vfs_writev+0x12e/0x440
> [<00000000a6b5639a>] do_writev+0x104/0x280
> [<00000000ccf065d8>] do_syscall_64+0x3b/0x90
> [<00000000d776e329>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> The issue occurs in the following scenarios:
> tun_get_user()
> napi_gro_frags()
> napi_frags_finish()
> case GRO_NORMAL:
> gro_normal_one()
> list_add_tail(&skb->list, &napi->rx_list);
> <-- While napi->rx_count < READ_ONCE(gro_normal_batch),
> <-- gro_normal_list() is not called, napi->rx_list is not empty
> <-- not ask to complete the gro work, will cause memory leaks in
> <-- following tun_napi_del()
> ...
> tun_napi_del()
> netif_napi_del()
> __netif_napi_del()
> <-- &napi->rx_list is not empty, which caused memory leaks
>
> To fix, add napi_complete() after napi_gro_frags().
>
> Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver")
> Signed-off-by: Wang Yufen <wangyufen@huawei.com>
> ---
> drivers/net/tun.c | 15 +++++----------
> 1 file changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index 27c6d23..910990d 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -1864,13 +1864,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
>
> if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
> atomic_long_inc(&tun->rx_frame_errors);
> - kfree_skb(skb);
> - if (frags) {
> - tfile->napi.skb = NULL;
> - mutex_unlock(&tfile->napi_mutex);
> - }
> -
> - return -EINVAL;
> + err = -EINVAL;
> + goto drop;
> }
>
> switch (tun->flags & TUN_TYPE_MASK) {
> @@ -1886,9 +1881,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
> pi.proto = htons(ETH_P_IPV6);
> break;
> default:
> - dev_core_stats_rx_dropped_inc(tun->dev);
> - kfree_skb(skb);
> - return -EINVAL;
> + err = -EINVAL;
> + goto drop;
> }
> }
>
> @@ -1976,6 +1970,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
>
> local_bh_disable();
> napi_gro_frags(&tfile->napi);
> + napi_complete(&tfile->napi);
> local_bh_enable();
> mutex_unlock(&tfile->napi_mutex);
> } else if (tfile->napi_enabled) {
^ permalink raw reply [flat|nested] 2+ messages in thread
* [PATCH net] net: tun: Fix memory leaks of napi_get_frags
@ 2022-11-02 9:30 Wang Yufen
2022-11-02 9:13 ` wangyufen
0 siblings, 1 reply; 2+ messages in thread
From: Wang Yufen @ 2022-11-02 9:30 UTC (permalink / raw)
To: netdev, bpf; +Cc: davem, edumazet, kuba, pabeni, peterpenkov96, Wang Yufen
kmemleak reports after running test_progs:
unreferenced object 0xffff8881b1672dc0 (size 232):
comm "test_progs", pid 394388, jiffies 4354712116 (age 841.975s)
hex dump (first 32 bytes):
e0 84 d7 a8 81 88 ff ff 80 2c 67 b1 81 88 ff ff .........,g.....
00 40 c5 9b 81 88 ff ff 00 00 00 00 00 00 00 00 .@..............
backtrace:
[<00000000c8f01748>] napi_skb_cache_get+0xd4/0x150
[<0000000041c7fc09>] __napi_build_skb+0x15/0x50
[<00000000431c7079>] __napi_alloc_skb+0x26e/0x540
[<000000003ecfa30e>] napi_get_frags+0x59/0x140
[<0000000099b2199e>] tun_get_user+0x183d/0x3bb0 [tun]
[<000000008a5adef0>] tun_chr_write_iter+0xc0/0x1b1 [tun]
[<0000000049993ff4>] do_iter_readv_writev+0x19f/0x320
[<000000008f338ea2>] do_iter_write+0x135/0x630
[<000000008a3377a4>] vfs_writev+0x12e/0x440
[<00000000a6b5639a>] do_writev+0x104/0x280
[<00000000ccf065d8>] do_syscall_64+0x3b/0x90
[<00000000d776e329>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
The issue occurs in the following scenarios:
tun_get_user()
napi_gro_frags()
napi_frags_finish()
case GRO_NORMAL:
gro_normal_one()
list_add_tail(&skb->list, &napi->rx_list);
<-- While napi->rx_count < READ_ONCE(gro_normal_batch),
<-- gro_normal_list() is not called, napi->rx_list is not empty
<-- not ask to complete the gro work, will cause memory leaks in
<-- following tun_napi_del()
...
tun_napi_del()
netif_napi_del()
__netif_napi_del()
<-- &napi->rx_list is not empty, which caused memory leaks
To fix, add napi_complete() after napi_gro_frags().
Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver")
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
---
drivers/net/tun.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 27c6d23..910990d 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1864,13 +1864,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
atomic_long_inc(&tun->rx_frame_errors);
- kfree_skb(skb);
- if (frags) {
- tfile->napi.skb = NULL;
- mutex_unlock(&tfile->napi_mutex);
- }
-
- return -EINVAL;
+ err = -EINVAL;
+ goto drop;
}
switch (tun->flags & TUN_TYPE_MASK) {
@@ -1886,9 +1881,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
pi.proto = htons(ETH_P_IPV6);
break;
default:
- dev_core_stats_rx_dropped_inc(tun->dev);
- kfree_skb(skb);
- return -EINVAL;
+ err = -EINVAL;
+ goto drop;
}
}
@@ -1976,6 +1970,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
local_bh_disable();
napi_gro_frags(&tfile->napi);
+ napi_complete(&tfile->napi);
local_bh_enable();
mutex_unlock(&tfile->napi_mutex);
} else if (tfile->napi_enabled) {
--
1.8.3.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
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2022-11-02 9:30 [PATCH net] net: tun: Fix memory leaks of napi_get_frags Wang Yufen
2022-11-02 9:13 ` wangyufen
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