syzbot

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BUG: KASAN: user-memory-access in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
BUG: KASAN: user-memory-access in atomic_fetch_add_unless include/linux/atomic.h:575 [inline]
BUG: KASAN: user-memory-access in atomic_add_unless include/linux/atomic.h:597 [inline]
BUG: KASAN: user-memory-access in dst_hold_safe include/net/dst.h:308 [inline]
BUG: KASAN: user-memory-access in ip6_hold_safe+0xa7/0x3a0 net/ipv6/route.c:1028
Read of size 4 at addr 000000000004b130 by task syz-executor.1/652

CPU: 1 PID: 652 Comm: syz-executor.1 Not tainted 4.19.53+ #25
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+0x172/0x1f0 lib/dump_stack.c:113
 kasan_report_error mm/kasan/report.c:352 [inline]
 kasan_report mm/kasan/report.c:412 [inline]
 kasan_report.cold+0x199/0x2ba mm/kasan/report.c:396
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x123/0x190 mm/kasan/kasan.c:267
 kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
 atomic_fetch_add_unless include/linux/atomic.h:575 [inline]
 atomic_add_unless include/linux/atomic.h:597 [inline]
 dst_hold_safe include/net/dst.h:308 [inline]
 ip6_hold_safe+0xa7/0x3a0 net/ipv6/route.c:1028
 rt6_get_pcpu_route net/ipv6/route.c:1250 [inline]
 ip6_pol_route+0x33d/0xf00 net/ipv6/route.c:1953
 ip6_pol_route_output+0x54/0x70 net/ipv6/route.c:2129
 fib6_rule_lookup+0x125/0x550 net/ipv6/fib6_rules.c:118
 ip6_route_output_flags+0x2c4/0x350 net/ipv6/route.c:2157
 ip6_route_output include/net/ip6_route.h:88 [inline]
 ip6_dst_lookup_tail+0xd10/0x1b30 net/ipv6/ip6_output.c:952
 ip6_dst_lookup_flow+0xa8/0x220 net/ipv6/ip6_output.c:1080
 sctp_v6_get_dst+0x785/0x1ce0 net/sctp/ipv6.c:290
 sctp_transport_route+0x12d/0x360 net/sctp/transport.c:311
 sctp_assoc_add_peer+0x53e/0xfc0 net/sctp/associola.c:676
 sctp_process_param net/sctp/sm_make_chunk.c:2539 [inline]
 sctp_process_init+0x2460/0x2ae0 net/sctp/sm_make_chunk.c:2360
 sctp_cmd_process_init net/sctp/sm_sideeffect.c:682 [inline]
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1389 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline]
 sctp_do_sm+0x3a3d/0x5190 net/sctp/sm_sideeffect.c:1170
 sctp_assoc_bh_rcv+0x343/0x660 net/sctp/associola.c:1072
 sctp_inq_push+0x1e4/0x280 net/sctp/inqueue.c:95
 sctp_backlog_rcv+0x189/0xbd0 net/sctp/input.c:351
 sk_backlog_rcv include/net/sock.h:941 [inline]
 __release_sock+0x129/0x3a0 net/core/sock.c:2337
 release_sock+0x59/0x1c0 net/core/sock.c:2853
 sctp_wait_for_connect+0x316/0x540 net/sctp/socket.c:8654
 __sctp_connect+0xab2/0xcd0 net/sctp/socket.c:1259
 __sctp_setsockopt_connectx+0x133/0x1a0 net/sctp/socket.c:1367
 sctp_setsockopt_connectx_old net/sctp/socket.c:1383 [inline]
 sctp_setsockopt net/sctp/socket.c:4338 [inline]
 sctp_setsockopt+0x2be9/0x4f70 net/sctp/socket.c:4302
 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:3044
 __sys_setsockopt+0x17a/0x280 net/socket.c:1901
 __do_sys_setsockopt net/socket.c:1912 [inline]
 __se_sys_setsockopt net/socket.c:1909 [inline]
 __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1909
 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4592c9
Code: fd 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f3a8868dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00000000004592c9
RDX: 000000000000006b RSI: 0000000000000084 RDI: 0000000000000007
RBP: 000000000075bf20 R08: 000000000000001c R09: 0000000000000000
R10: 000000002055bfe4 R11: 0000000000000246 R12: 00007f3a8868e6d4
R13: 00000000004ced98 R14: 00000000004dd4f0 R15: 00000000ffffffff
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