KMSAN: uninit-value in bpf_skb_load_helper_32_no

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KMSAN: uninit-value in bpf_skb_load_helper_32_no_cache net bpf				2	1540d	1538d	15/26	fixed on 2020/04/15 17:19
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BUG: KMSAN: uninit-value in __arch_swab32 arch/x86/include/uapi/asm/swab.h:10 [inline]
BUG: KMSAN: uninit-value in __fswab32 include/uapi/linux/swab.h:60 [inline]
BUG: KMSAN: uninit-value in __swab32p include/uapi/linux/swab.h:189 [inline]
BUG: KMSAN: uninit-value in __be32_to_cpup include/uapi/linux/byteorder/little_endian.h:82 [inline]
BUG: KMSAN: uninit-value in get_unaligned_be32 include/linux/unaligned/access_ok.h:30 [inline]
BUG: KMSAN: uninit-value in ____bpf_skb_load_helper_32 net/core/filter.c:246 [inline]
BUG: KMSAN: uninit-value in ____bpf_skb_load_helper_32_no_cache net/core/filter.c:255 [inline]
BUG: KMSAN: uninit-value in bpf_skb_load_helper_32_no_cache+0x2cb/0x390 net/core/filter.c:252
CPU: 0 PID: 27867 Comm: syz-executor.4 Not tainted 5.7.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x220 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
 __arch_swab32 arch/x86/include/uapi/asm/swab.h:10 [inline]
 __fswab32 include/uapi/linux/swab.h:60 [inline]
 __swab32p include/uapi/linux/swab.h:189 [inline]
 __be32_to_cpup include/uapi/linux/byteorder/little_endian.h:82 [inline]
 get_unaligned_be32 include/linux/unaligned/access_ok.h:30 [inline]
 ____bpf_skb_load_helper_32 net/core/filter.c:246 [inline]
 ____bpf_skb_load_helper_32_no_cache net/core/filter.c:255 [inline]
 bpf_skb_load_helper_32_no_cache+0x2cb/0x390 net/core/filter.c:252
 ___bpf_prog_run+0x214d/0x97a0 kernel/bpf/core.c:1516
 __bpf_prog_run32+0x12e/0x190 kernel/bpf/core.c:1692
 bpf_dispatcher_nop_func include/linux/bpf.h:545 [inline]
 bpf_prog_run_pin_on_cpu include/linux/filter.h:599 [inline]
 bpf_prog_run_clear_cb include/linux/filter.h:721 [inline]
 run_filter net/packet/af_packet.c:2012 [inline]
 packet_rcv+0x70f/0x2160 net/packet/af_packet.c:2085
 deliver_skb net/core/dev.c:2168 [inline]
 dev_queue_xmit_nit+0x862/0x1270 net/core/dev.c:2238
 xmit_one net/core/dev.c:3473 [inline]
 dev_hard_start_xmit+0x20f/0xab0 net/core/dev.c:3493
 __dev_queue_xmit+0x2f8d/0x3b20 net/core/dev.c:4052
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:4085
 __netlink_deliver_tap_skb net/netlink/af_netlink.c:294 [inline]
 __netlink_deliver_tap net/netlink/af_netlink.c:312 [inline]
 netlink_deliver_tap+0x9d4/0xea0 net/netlink/af_netlink.c:325
 __netlink_sendskb net/netlink/af_netlink.c:1247 [inline]
 netlink_dump+0xde6/0x1a90 net/netlink/af_netlink.c:2256
 __netlink_dump_start+0xbc5/0xd00 net/netlink/af_netlink.c:2353
 netlink_dump_start include/linux/netlink.h:246 [inline]
 inet_diag_handler_cmd+0x737/0x820 net/ipv4/inet_diag.c:1240
 sock_diag_rcv_msg+0x211/0x610 net/core/sock_diag.c:256
 netlink_rcv_skb+0x451/0x650 net/netlink/af_netlink.c:2469
 sock_diag_rcv+0x63/0x80 net/core/sock_diag.c:275
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0xf9e/0x1100 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x1246/0x14d0 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x12b6/0x1350 net/socket.c:2362
 ___sys_sendmsg net/socket.c:2416 [inline]
 __sys_sendmsg+0x623/0x750 net/socket.c:2449
 __do_sys_sendmsg net/socket.c:2458 [inline]
 __se_sys_sendmsg+0x97/0xb0 net/socket.c:2456
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2456
 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45ca69
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6eccdf7c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000500dc0 RCX: 000000000045ca69
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000005
RBP: 000000000078c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000009fd R14: 00000000004ccd99 R15: 00007f6eccdf86d4

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
 kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127
 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:80
 slab_alloc_node mm/slub.c:2802 [inline]
 __kmalloc_node_track_caller+0xb40/0x1200 mm/slub.c:4436
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x2fd/0xac0 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1083 [inline]
 netlink_dump+0x42f/0x1a90 net/netlink/af_netlink.c:2225
 __netlink_dump_start+0xbc5/0xd00 net/netlink/af_netlink.c:2353
 netlink_dump_start include/linux/netlink.h:246 [inline]
 inet_diag_handler_cmd+0x737/0x820 net/ipv4/inet_diag.c:1240
 sock_diag_rcv_msg+0x211/0x610 net/core/sock_diag.c:256
 netlink_rcv_skb+0x451/0x650 net/netlink/af_netlink.c:2469
 sock_diag_rcv+0x63/0x80 net/core/sock_diag.c:275
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0xf9e/0x1100 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x1246/0x14d0 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x12b6/0x1350 net/socket.c:2362
 ___sys_sendmsg net/socket.c:2416 [inline]
 __sys_sendmsg+0x623/0x750 net/socket.c:2449
 __do_sys_sendmsg net/socket.c:2458 [inline]
 __se_sys_sendmsg+0x97/0xb0 net/socket.c:2456
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2456
 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
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