From c7848399ec7612c2fa4dc0c2eeb9e0b89d00afef Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Mon, 28 Aug 2017 17:10:51 -0700 Subject: net: dsa: Don't dereference dst->cpu_dp->netdev If we do not have a master network device attached dst->cpu_dp will be NULL and accessing cpu_dp->netdev will create a trace similar to the one below. The correct check is on dst->cpu_dp period. [ 1.004650] DSA: switch 0 0 parsed [ 1.008078] Unable to handle kernel NULL pointer dereference at virtual address 00000010 [ 1.016195] pgd = c0003000 [ 1.018918] [00000010] *pgd=80000000004003, *pmd=00000000 [ 1.024349] Internal error: Oops: 206 [#1] SMP ARM [ 1.029157] Modules linked in: [ 1.032228] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.13.0-rc6-00071-g45b45afab9bd-dirty #7 [ 1.040772] Hardware name: Broadcom STB (Flattened Device Tree) [ 1.046704] task: ee08f840 task.stack: ee090000 [ 1.051258] PC is at dsa_register_switch+0x5e0/0x9dc [ 1.056234] LR is at dsa_register_switch+0x5d0/0x9dc [ 1.061211] pc : [] lr : [] psr: 60000213 [ 1.067491] sp : ee091d88 ip : 00000000 fp : 0000000c [ 1.072728] r10: 00000000 r9 : 00000001 r8 : ee208010 [ 1.077965] r7 : ee2b57b0 r6 : ee2b5780 r5 : 00000000 r4 : ee208e0c [ 1.084506] r3 : 00000000 r2 : 00040d00 r1 : 2d1b2000 r0 : 00000016 [ 1.091050] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user [ 1.098199] Control: 32c5387d Table: 00003000 DAC: fffffffd [ 1.103957] Process swapper/0 (pid: 1, stack limit = 0xee090210) Reported-by: Dan Carpenter Fixes: 6d3c8c0dd88a ("net: dsa: Remove master_netdev and use dst->cpu_dp->netdev") Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller --- net/dsa/dsa2.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c index c442051d5a55..20bc9c56fca0 100644 --- a/net/dsa/dsa2.c +++ b/net/dsa/dsa2.c @@ -577,7 +577,7 @@ static int dsa_dst_parse(struct dsa_switch_tree *dst) return err; } - if (!dst->cpu_dp->netdev) { + if (!dst->cpu_dp) { pr_warn("Tree has no master device\n"); return -EINVAL; } -- cgit v1.2.3-58-ga151