[PATCH AUTOSEL 4.9 28/45] net: thunderx: fix NULL pointer dereference in nic_remove

Sasha Levin
2018-12-05T09:50:34Z

From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>

[ Upstream commit 24a6d2dd263bc910de018c78d1148b3e33b94512 ]

Fix a possible NULL pointer dereference in nic_remove routine
removing the nicpf module if nic_probe fails.
The issue can be triggered with the following reproducer:

$rmmod nicvf
$rmmod nicpf

[ 521.412008] Unable to handle kernel access to user memory outside uaccess routines at virtual address 0000000000000014
[ 521.422777] Mem abort info:
[ 521.425561] ESR = 0x96000004
[ 521.428624] Exception class = DABT (current EL), IL = 32 bits
[ 521.434535] SET = 0, FnV = 0
[ 521.437579] EA = 0, S1PTW = 0
[ 521.440730] Data abort info:
[ 521.443603] ISV = 0, ISS = 0x00000004
[ 521.447431] CM = 0, WnR = 0
[ 521.450417] user pgtable: 4k pages, 48-bit VAs, pgdp = 0000000072a3da42
[ 521.457022] [0000000000000014] pgd=0000000000000000
[ 521.461916] Internal error: Oops: 96000004 [#1] SMP
[ 521.511801] Hardware name: GIGABYTE H270-T70/MT70-HD0, BIOS T49 02/02/2018
[ 521.518664] pstate: 80400005 (Nzcv daif +PAN -UAO)
[ 521.523451] pc : nic_remove+0x24/0x88 [nicpf]
[ 521.527808] lr : pci_device_remove+0x48/0xd8
[ 521.532066] sp : ffff000013433cc0
[ 521.535370] x29: ffff000013433cc0 x28: ffff810f6ac50000
[ 521.540672] x27: 0000000000000000 x26: 0000000000000000
[ 521.545974] x25: 0000000056000000 x24: 0000000000000015
[ 521.551274] x23: ffff8007ff89a110 x22: ffff000001667070
[ 521.556576] x21: ffff8007ffb170b0 x20: ffff8007ffb17000
[ 521.561877] x19: 0000000000000000 x18: 0000000000000025
[ 521.567178] x17: 0000000000000000 x16: 000000000000010ffc33ff98 x8 : 0000000000000000
[ 521.593683] x7 : 0000000000000000 x6 : 0000000000000001
[ 521.598983] x5 : 0000000000000002 x4 : 0000000000000003
[ 521.604284] x3 : ffff8007ffb17184 x2 : ffff8007ffb17184
[ 521.609585] x1 : ffff000001662118 x0 : ffff000008557be0
[ 521.614887] Process rmmod (pid: 1897, stack limit = 0x00000000859535c3)
[ 521.621490] Call trace:
[ 521.623928] nic_remove+0x24/0x88 [nicpf]
[ 521.627927] pci_device_remove+0x48/0xd8
[ 521.631847] device_release_driver_internal+0x1b0/0x248
[ 521.637062] driver_detach+0x50/0xc0
[ 521.640628] bus_remove_driver+0x60/0x100
[ 521.644627] driver_unregister+0x34/0x60
[ 521.648538] pci_unregister_driver+0x24/0xd8
[ 521.652798] nic_cleanup_module+0x14/0x111c [nicpf]
[ 521.657672] __arm64_sys_delete_module+0x150/0x218
[ 521.662460] el0_svc_handler+0x94/0x110
[ 521.666287] el0_svc+0x8/0xc
[ 521.669160] Code: aa1e03e0 9102c295 d503201f f9404eb3 (b9401660)

Fixes: 4863dea3fab0 ("net: Adding support for Cavium ThunderX network controller")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/cavium/thunder/nic_main.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/cavium/thunder/nic_main.c b/drivers/net/ethernet/cavium/thunder/nic_main.c
index 6677b96e1f3f..da142f6bd0c3 100644
--- a/drivers/net/ethernet/cavium/thunder/nic_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nic_main.c
@@ -1371,6 +1371,9 @@ static void nic_remove(struct pci_dev *pdev)
{
struct nicpf *nic = pci_get_drvdata(pdev);

+ if (!nic)
+ return;
+
if (nic->flags & NIC_SRIOV_ENABLED)
pci_disable_sriov(pdev);

--
2.17.1