diff options
| author | Michael Braun <michael-dev@fami-braun.de> | 2021-03-04 20:52:52 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-03-05 13:13:32 -0800 |
| commit | d8861bab48b6c1fc3cdbcab8ff9d1eaea43afe7f (patch) | |
| tree | 2e9d2ce85e8e2696b9018404cbdf16671dca7068 /drivers/net/ethernet/freescale/gianfar.c | |
| parent | 155b23e6e53475ca3b8c2a946299b4d4dd6a5a1e (diff) | |
gianfar: fix jumbo packets+napi+rx overrun crash
When using jumbo packets and overrunning rx queue with napi enabled,
the following sequence is observed in gfar_add_rx_frag:
| lstatus | | skb |
t | lstatus, size, flags | first | len, data_len, *ptr |
---+--------------------------------------+-------+-----------------------+
13 | 18002348, 9032, INTERRUPT LAST | 0 | 9600, 8000, f554c12e |
12 | 10000640, 1600, INTERRUPT | 0 | 8000, 6400, f554c12e |
11 | 10000640, 1600, INTERRUPT | 0 | 6400, 4800, f554c12e |
10 | 10000640, 1600, INTERRUPT | 0 | 4800, 3200, f554c12e |
09 | 10000640, 1600, INTERRUPT | 0 | 3200, 1600, f554c12e |
08 | 14000640, 1600, INTERRUPT FIRST | 0 | 1600, 0, f554c12e |
07 | 14000640, 1600, INTERRUPT FIRST | 1 | 0, 0, f554c12e |
06 | 1c000080, 128, INTERRUPT LAST FIRST | 1 | 0, 0, abf3bd6e |
05 | 18002348, 9032, INTERRUPT LAST | 0 | 8000, 6400, c5a57780 |
04 | 10000640, 1600, INTERRUPT | 0 | 6400, 4800, c5a57780 |
03 | 10000640, 1600, INTERRUPT | 0 | 4800, 3200, c5a57780 |
02 | 10000640, 1600, INTERRUPT | 0 | 3200, 1600, c5a57780 |
01 | 10000640, 1600, INTERRUPT | 0 | 1600, 0, c5a57780 |
00 | 14000640, 1600, INTERRUPT FIRST | 1 | 0, 0, c5a57780 |
So at t=7 a new packets is started but not finished, probably due to rx
overrun - but rx overrun is not indicated in the flags. Instead a new
packets starts at t=8. This results in skb->len to exceed size for the LAST
fragment at t=13 and thus a negative fragment size added to the skb.
This then crashes:
kernel BUG at include/linux/skbuff.h:2277!
Oops: Exception in kernel mode, sig: 5 [#1]
...
NIP [c04689f4] skb_pull+0x2c/0x48
LR [c03f62ac] gfar_clean_rx_ring+0x2e4/0x844
Call Trace:
[ec4bfd38] [c06a84c4] _raw_spin_unlock_irqrestore+0x60/0x7c (unreliable)
[ec4bfda8] [c03f6a44] gfar_poll_rx_sq+0x48/0xe4
[ec4bfdc8] [c048d504] __napi_poll+0x54/0x26c
[ec4bfdf8] [c048d908] net_rx_action+0x138/0x2c0
[ec4bfe68] [c06a8f34] __do_softirq+0x3a4/0x4fc
[ec4bfed8] [c0040150] run_ksoftirqd+0x58/0x70
[ec4bfee8] [c0066ecc] smpboot_thread_fn+0x184/0x1cc
[ec4bff08] [c0062718] kthread+0x140/0x144
[ec4bff38] [c0012350] ret_from_kernel_thread+0x14/0x1c
This patch fixes this by checking for computed LAST fragment size, so a
negative sized fragment is never added.
In order to prevent the newer rx frame from getting corrupted, the FIRST
flag is checked to discard the incomplete older frame.
Signed-off-by: Michael Braun <michael-dev@fami-braun.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/freescale/gianfar.c')
| -rw-r--r-- | drivers/net/ethernet/freescale/gianfar.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c index 541de32ea662..1cf8ef717453 100644 --- a/drivers/net/ethernet/freescale/gianfar.c +++ b/drivers/net/ethernet/freescale/gianfar.c @@ -2390,6 +2390,10 @@ static bool gfar_add_rx_frag(struct gfar_rx_buff *rxb, u32 lstatus, if (lstatus & BD_LFLAG(RXBD_LAST)) size -= skb->len; + WARN(size < 0, "gianfar: rx fragment size underflow"); + if (size < 0) + return false; + skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, rxb->page_offset + RXBUF_ALIGNMENT, size, GFAR_RXB_TRUESIZE); @@ -2552,6 +2556,17 @@ static int gfar_clean_rx_ring(struct gfar_priv_rx_q *rx_queue, if (lstatus & BD_LFLAG(RXBD_EMPTY)) break; + /* lost RXBD_LAST descriptor due to overrun */ + if (skb && + (lstatus & BD_LFLAG(RXBD_FIRST))) { + /* discard faulty buffer */ + dev_kfree_skb(skb); + skb = NULL; + rx_queue->stats.rx_dropped++; + + /* can continue normally */ + } + /* order rx buffer descriptor reads */ rmb(); |