net: rmnet: use upper/lower device infrastructure
netdev_upper_dev_link() is useful to manage lower/upper interfaces. And this function internally validates looping, maximum depth. All or most virtual interfaces that could have a real interface (e.g. macsec, macvlan, ipvlan etc.) use lower/upper infrastructure. Test commands: modprobe rmnet ip link add dummy0 type dummy ip link add rmnet1 link dummy0 type rmnet mux_id 1 for i in {2..100} do let A=$i-1 ip link add rmnet$i link rmnet$A type rmnet mux_id $i done ip link del dummy0 The purpose of the test commands is to make stack overflow. Splat looks like: [ 52.411438][ T1395] BUG: KASAN: slab-out-of-bounds in find_busiest_group+0x27e/0x2c00 [ 52.413218][ T1395] Write of size 64 at addr ffff8880c774bde0 by task ip/1395 [ 52.414841][ T1395] [ 52.430720][ T1395] CPU: 1 PID: 1395 Comm: ip Not tainted 5.6.0-rc1+ #447 [ 52.496511][ T1395] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 52.513597][ T1395] Call Trace: [ 52.546516][ T1395] [ 52.558773][ T1395] Allocated by task 3171537984: [ 52.588290][ T1395] BUG: unable to handle page fault for address: ffffffffb999e260 [ 52.589311][ T1395] #PF: supervisor read access in kernel mode [ 52.590529][ T1395] #PF: error_code(0x0000) - not-present page [ 52.591374][ T1395] PGD d6818067 P4D d6818067 PUD d6819063 PMD 0 [ 52.592288][ T1395] Thread overran stack, or stack corrupted [ 52.604980][ T1395] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI [ 52.605856][ T1395] CPU: 1 PID: 1395 Comm: ip Not tainted 5.6.0-rc1+ #447 [ 52.611764][ T1395] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 52.621520][ T1395] RIP: 0010:stack_depot_fetch+0x10/0x30 [ 52.622296][ T1395] Code: ff e9 f9 fe ff ff 48 89 df e8 9c 1d 91 ff e9 ca fe ff ff cc cc cc cc cc cc cc 89 f8 0 [ 52.627887][ T1395] RSP: 0018:ffff8880c774bb60 EFLAGS: 00010006 [ 52.628735][ T1395] RAX: 00000000001f8880 RBX: ffff8880c774d140 RCX: 0000000000000000 [ 52.631773][ T1395] RDX: 000000000000001d RSI: ffff8880c774bb68 RDI: 0000000000003ff0 [ 52.649584][ T1395] RBP: ffffea00031dd200 R08: ffffed101b43e403 R09: ffffed101b43e403 [ 52.674857][ T1395] R10: 0000000000000001 R11: ffffed101b43e402 R12: ffff8880d900e5c0 [ 52.678257][ T1395] R13: ffff8880c774c000 R14: 0000000000000000 R15: dffffc0000000000 [ 52.694541][ T1395] FS: 00007fe867f6e0c0(0000) GS:ffff8880da000000(0000) knlGS:0000000000000000 [ 52.764039][ T1395] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 52.815008][ T1395] CR2: ffffffffb999e260 CR3: 00000000c26aa005 CR4: 00000000000606e0 [ 52.862312][ T1395] Call Trace: [ 52.887133][ T1395] Modules linked in: dummy rmnet veth openvswitch nsh nf_conncount nf_nat nf_conntrack nf_dex [ 52.936749][ T1395] CR2: ffffffffb999e260 [ 52.965695][ T1395] ---[ end trace 7e32ca99482dbb31 ]--- [ 52.966556][ T1395] RIP: 0010:stack_depot_fetch+0x10/0x30 [ 52.971083][ T1395] Code: ff e9 f9 fe ff ff 48 89 df e8 9c 1d 91 ff e9 ca fe ff ff cc cc cc cc cc cc cc 89 f8 0 [ 53.003650][ T1395] RSP: 0018:ffff8880c774bb60 EFLAGS: 00010006 [ 53.043183][ T1395] RAX: 00000000001f8880 RBX: ffff8880c774d140 RCX: 0000000000000000 [ 53.076480][ T1395] RDX: 000000000000001d RSI: ffff8880c774bb68 RDI: 0000000000003ff0 [ 53.093858][ T1395] RBP: ffffea00031dd200 R08: ffffed101b43e403 R09: ffffed101b43e403 [ 53.112795][ T1395] R10: 0000000000000001 R11: ffffed101b43e402 R12: ffff8880d900e5c0 [ 53.139837][ T1395] R13: ffff8880c774c000 R14: 0000000000000000 R15: dffffc0000000000 [ 53.141500][ T1395] FS: 00007fe867f6e0c0(0000) GS:ffff8880da000000(0000) knlGS:0000000000000000 [ 53.143343][ T1395] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 53.152007][ T1395] CR2: ffffffffb999e260 CR3: 00000000c26aa005 CR4: 00000000000606e0 [ 53.156459][ T1395] Kernel panic - not syncing: Fatal exception [ 54.213570][ T1395] Shutting down cpus with NMI [ 54.354112][ T1395] Kernel Offset: 0x33000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0x) [ 54.355687][ T1395] Rebooting in 5 seconds.. Fixes: b37f78f2 ("net: qualcomm: rmnet: Fix crash on real dev unregistration") Signed-off-by: NTaehee Yoo <ap420073@gmail.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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