[PATCH 6.0 0519/1073] net: farsync: Fix kmemleak when rmmods farsync

Greg Kroah-Hartman
2022-12-28T16:02:23Z

From: Li Zetao <lizetao1@huawei.com>

[ Upstream commit 2f623aaf9f31de968dea6169849706a2f9be444c ]

There are two memory leaks reported by kmemleak:

unreferenced object 0xffff888114b20200 (size 128):
comm "modprobe", pid 4846, jiffies 4295146524 (age 401.345s)
hex dump (first 32 bytes):
e0 62 57 09 81 88 ff ff e0 62 57 09 81 88 ff ff .bW......bW.....
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff815bcd82>] kmalloc_trace+0x22/0x60
[<ffffffff83d35c78>] __hw_addr_add_ex+0x198/0x6c0
[<ffffffff83d3989d>] dev_addr_init+0x13d/0x230
[<ffffffff83d1063d>] alloc_netdev_mqs+0x10d/0xe50
[<ffffffff82b4a06e>] alloc_hdlcdev+0x2e/0x80
[<ffffffffa016a741>] fst_add_one+0x601/0x10e0 [farsync]
...

unreferenced object 0xffff88810b85b000 (size 1024):
comm "modprobe", pid 4846, jiffies 4295146523 (age 401.346s)
hex dump (first 32 bytes):
00 00 b0 02 00 c9 ff ff 00 70 0a 00 00 c9 ff ff .........p......
00 00 00 f2 00 00 00 f3 0a 00 00 00 02 00 00 00 ................
backtrace:
[<ffffffff815bcd82>] kmalloc_trace+0x22/0x60
[<ffffffffa016a294>] fst_add_one+0x154/0x10e0 [farsync]
[<ffffffff82060e83>] local_pci_probe+0xd3/0x170
...

The root cause is traced to the netdev and fst_card_info are not freed
when removes one fst in fst_remove_one(), which may trigger oom if
repeated insmod and rmmod module.

Fix it by adding free_netdev() and kfree() in fst_remove_one(), just as
the operations on the error handling path in fst_add_one().

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wan/farsync.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/net/wan/farsync.c b/drivers/net/wan/farsync.c
index 6a212c085435..5b01642ca44e 100644
--- a/drivers/net/wan/farsync.c
+++ b/drivers/net/wan/farsync.c
@@ -2545,6 +2545,7 @@ fst_remove_one(struct pci_dev *pdev)
struct net_device *dev = port_to_dev(&card->ports[i]);

unregister_hdlc_device(dev);
+ free_netdev(dev);
}

fst_disable_intr(card);
@@ -2564,6 +2565,7 @@ fst_remove_one(struct pci_dev *pdev)
card->tx_dma_handle_card);
}
fst_card_array[card->card_no] = NULL;
+ kfree(card);
}

static struct pci_driver fst_driver = {
--
2.35.1