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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:1023
Read of size 4 at addr 0000000000023b30 by task syz-executor.0/30527

CPU: 0 PID: 30527 Comm: syz-executor.0 Not tainted 5.0.0-rc5+ #55
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.cold+0x5/0x40 mm/kasan/report.c:321
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x123/0x190 mm/kasan/generic.c:191
 kasan_check_read+0x11/0x20 mm/kasan/common.c:100
 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:1023
 rt6_get_pcpu_route net/ipv6/route.c:1243 [inline]
 ip6_pol_route+0x33d/0xf00 net/ipv6/route.c:1892
 ip6_pol_route_output+0x54/0x70 net/ipv6/route.c:2068
 __fib6_rule_action net/ipv6/fib6_rules.c:233 [inline]
 fib6_rule_action+0x3ac/0xab0 net/ipv6/fib6_rules.c:264
 fib_rules_lookup+0x351/0xa90 net/core/fib_rules.c:304
 fib6_rule_lookup+0x33c/0x560 net/ipv6/fib6_rules.c:110
 ip6_route_output_flags+0x2c4/0x350 net/ipv6/route.c:2097
 ip6_route_output include/net/ip6_route.h:88 [inline]
 ip6_dst_lookup_tail+0xd10/0x1b30 net/ipv6/ip6_output.c:958
 ip6_dst_lookup_flow+0xa8/0x220 net/ipv6/ip6_output.c:1086
 ip6_datagram_dst_update+0x5cf/0xc20 net/ipv6/datagram.c:91
 __ip6_datagram_connect+0x5e9/0x1390 net/ipv6/datagram.c:250
 ip6_datagram_connect+0x30/0x50 net/ipv6/datagram.c:273
 inet_dgram_connect+0x150/0x2e0 net/ipv4/af_inet.c:571
 __sys_connect+0x266/0x330 net/socket.c:1684
 __do_sys_connect net/socket.c:1695 [inline]
 __se_sys_connect net/socket.c:1692 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:1692
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457e39
Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f409510ec78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457e39
RDX: 000000000000001c RSI: 0000000020000040 RDI: 0000000000000004
RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f409510f6d4
R13: 00000000004be271 R14: 00000000004ce930 R15: 00000000ffffffff
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