On Thu, Oct 26, 2017 at 2:51 PM, Alexander Potapenko <gli...@google.com> wrote: > Hi David, Eric, > > I've changed KMSAN instrumentation a bit and it's now reporting a new > error (see below) when I SSH into a VM. I've double-checked the old instrumentation and found a bug in it, which led to masking some of the errors on uninitialized bitfields. I now believe this is a true positive report. > For |req| allocated by inet_reqsk_alloc() the value of > req_to_sk(req)->sk_reuseport is uninitialized. > Does this look valid? > I'm a bit surprised this didn't show up before, but I couldn't find > any code to initialize sk_reuseport. > > ================================================================== > BUG: KMSAN: use of uninitialized memory in inet_ehash_insert+0xd40/0x1050 > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.13.0+ #3288 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > Call Trace: > <IRQ> > __dump_stack lib/dump_stack.c:16 > dump_stack+0x185/0x1d0 lib/dump_stack.c:52 > kmsan_report+0x13f/0x1c0 mm/kmsan/kmsan.c:1016 > __msan_warning_32+0x69/0xb0 mm/kmsan/kmsan_instr.c:766 > __sk_nulls_add_node_rcu ./include/net/sock.h:684 > inet_ehash_insert+0xd40/0x1050 net/ipv4/inet_hashtables.c:413 > reqsk_queue_hash_req net/ipv4/inet_connection_sock.c:754 > inet_csk_reqsk_queue_hash_add+0x1cc/0x300 net/ipv4/inet_connection_sock.c:765 > tcp_conn_request+0x31e7/0x36f0 net/ipv4/tcp_input.c:6414 > tcp_v4_conn_request+0x16d/0x220 net/ipv4/tcp_ipv4.c:1314 > tcp_rcv_state_process+0x42a/0x7210 net/ipv4/tcp_input.c:5917 > tcp_v4_do_rcv+0xa6a/0xcd0 net/ipv4/tcp_ipv4.c:1483 > tcp_v4_rcv+0x3de0/0x4ab0 net/ipv4/tcp_ipv4.c:1763 > ip_local_deliver_finish+0x6bb/0xcb0 net/ipv4/ip_input.c:216 > NF_HOOK ./include/linux/netfilter.h:248 > ip_local_deliver+0x3fa/0x480 net/ipv4/ip_input.c:257 > dst_input ./include/net/dst.h:477 > ip_rcv_finish+0x6fb/0x1540 net/ipv4/ip_input.c:397 > NF_HOOK ./include/linux/netfilter.h:248 > ip_rcv+0x10f6/0x15c0 net/ipv4/ip_input.c:488 > __netif_receive_skb_core+0x36f6/0x3f60 net/core/dev.c:4298 > __netif_receive_skb net/core/dev.c:4336 > netif_receive_skb_internal+0x63c/0x19c0 net/core/dev.c:4497 > napi_skb_finish net/core/dev.c:4858 > napi_gro_receive+0x629/0xa50 net/core/dev.c:4889 > e1000_receive_skb drivers/net/ethernet/intel/e1000/e1000_main.c:4018 > e1000_clean_rx_irq+0x1492/0x1d30 > drivers/net/ethernet/intel/e1000/e1000_main.c:4474 > e1000_clean+0x43aa/0x5970 drivers/net/ethernet/intel/e1000/e1000_main.c:3819 > napi_poll net/core/dev.c:5500 > net_rx_action+0x73c/0x1820 net/core/dev.c:5566 > __do_softirq+0x4b4/0x8dd kernel/softirq.c:284 > invoke_softirq kernel/softirq.c:364 > irq_exit+0x203/0x240 kernel/softirq.c:405 > exiting_irq+0xe/0x10 ./arch/x86/include/asm/apic.h:638 > do_IRQ+0x15e/0x1a0 arch/x86/kernel/irq.c:263 > common_interrupt+0x86/0x86 > ... > </IRQ> > arch_cpu_idle+0x20/0x30 arch/x86/kernel/process.c:332 > default_idle_call kernel/sched/idle.c:98 > cpuidle_idle_call kernel/sched/idle.c:156 > do_idle+0x334/0x730 kernel/sched/idle.c:246 > cpu_startup_entry+0x35/0x40 kernel/sched/idle.c:351 > rest_init+0xb8/0xc0 init/main.c:437 > start_kernel+0x4d7/0x530 init/main.c:703 > x86_64_start_reservations arch/x86/kernel/head64.c:318 > x86_64_start_kernel+0x3cd/0x3e0 arch/x86/kernel/head64.c:299 > secondary_startup_64+0x9f/0x9f arch/x86/kernel/head_64.S:219 > origin: > save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 > kmsan_save_stack_with_flags mm/kmsan/kmsan.c:302 > kmsan_internal_poison_shadow+0xb3/0x1b0 mm/kmsan/kmsan.c:198 > kmsan_kmalloc+0x80/0xe0 mm/kmsan/kmsan.c:337 > kmem_cache_alloc+0x1e2/0x220 mm/slub.c:2756 > reqsk_alloc ./include/net/request_sock.h:88 > inet_reqsk_alloc+0xb8/0x6b0 net/ipv4/tcp_input.c:6231 > tcp_conn_request+0x89d/0x36f0 net/ipv4/tcp_input.c:6330 > tcp_v4_conn_request+0x16d/0x220 net/ipv4/tcp_ipv4.c:1314 > tcp_rcv_state_process+0x42a/0x7210 net/ipv4/tcp_input.c:5917 > tcp_v4_do_rcv+0xa6a/0xcd0 net/ipv4/tcp_ipv4.c:1483 > tcp_v4_rcv+0x3de0/0x4ab0 net/ipv4/tcp_ipv4.c:1763 > ip_local_deliver_finish+0x6bb/0xcb0 net/ipv4/ip_input.c:216 > NF_HOOK ./include/linux/netfilter.h:248 > ... > ================================================================== > > -- > Alexander Potapenko > Software Engineer > > Google Germany GmbH > Erika-Mann-Straße, 33 > 80636 München > > Geschäftsführer: Paul Manicle, Halimah DeLaine Prado > Registergericht und -nummer: Hamburg, HRB 86891 > Sitz der Gesellschaft: Hamburg
-- Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Straße, 33 80636 München Geschäftsführer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg
