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FS#3015 - ag71xx crashes after increasing MTU #7782

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openwrt-bot opened this issue Apr 18, 2020 · 1 comment
Open

FS#3015 - ag71xx crashes after increasing MTU #7782

openwrt-bot opened this issue Apr 18, 2020 · 1 comment
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flyspray kernel pull request/issue with Linux kernel related changes release/19.07 pull request/issue targeted (also) for OpenWrt 19.07 release

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@openwrt-bot
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rkreis:

Tested on openwrt-19.07.2-ath79-generic-tplink_archer-c7-v5

Steps to reproduce:

root@OpenWrt:# ip link set eth0 mtu 500
root@OpenWrt:
# ip link set eth0 down; ip link set eth0 up
root@OpenWrt:~# ip link set eth0 mtu 1500

After this, sending a large packet (ping -s 800) causes a kernel panic:

skbuff: skb_over_panic: text:802da154 len:846 put:846 head:8677e3e0 data:8677e422 tail:0x8677e770 end:0x8677e640 dev:

The problem is the rx buffer management in target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c: ag71xx_change_mtu adjusts the MTU, but doesn't adjust rx_buf_size (it's only set in ag71xx_open).

The attached patch fixes it by always using a large receive buffer. Maybe it is better to change rx_buf_size from ag71xx_change_mtu, but I don't know how to do that.

@openwrt-bot
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ynezz:

Please send the patch to the mailing list, see https://openwrt.org/submitting-patches for details, thanks.

@aparcar aparcar added release/19.07 pull request/issue targeted (also) for OpenWrt 19.07 release kernel pull request/issue with Linux kernel related changes labels Feb 22, 2022
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Labels
flyspray kernel pull request/issue with Linux kernel related changes release/19.07 pull request/issue targeted (also) for OpenWrt 19.07 release
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