Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

net: fec: Use page_pool_put_full_page when freeing rx buffers

The page_pool_release_page was used when freeing rx buffers, and this function just unmaps the page (if mapped) and does not recycle the page. So after hundreds of down/up the eth0, the system will out of memory. For more details, please refer to the following reproduce steps and bug logs. To solve this issue and refer to the doc of page pool, the page_pool_put_full_page should be used to replace page_pool_release_page. Because this API will try to recycle the page if the page refcnt equal to 1. After testing 20000 times, the issue can not be reproduced anymore (about testing 391 times the issue will occur on i.MX8MN-EVK before).

Reproduce steps: Create the test script and run the script. The script content is as follows: LOOPS=20000 i=1 while [ $i -le $LOOPS ] do echo "TINFO:ENET $curface up and down test $i times" org_macaddr=$(cat /sys/class/net/eth0/address) ifconfig eth0 down ifconfig eth0 hw ether $org_macaddr up i=$(expr $i + 1) done sleep 5 if cat /sys/class/net/eth0/operstate | grep 'up';then echo "TEST PASS" else echo "TEST FAIL" fi

Bug detail logs: TINFO:ENET up and down test 391 times [ 850.471205] Qualcomm Atheros AR8031/AR8033 30be0000.ethernet-1:00: attached PHY driver (mii_bus:phy_addr=30be0000.ethernet-1:00, irq=POLL) [ 853.535318] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready [ 853.5…