================================================================== BUG: KASAN: slab-out-of-bounds in fib6_nh_get_excptn_bucket+0x198/0x1b0 net/ipv6/route.c:1591 Read of size 8 at addr ffff8880a8a4fbf8 by task syz-executor.2/6194 CPU: 0 PID: 6194 Comm: syz-executor.2 Not tainted 5.3.0-rc7+ #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+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482 kasan_report+0x12/0x17 mm/kasan/common.c:618 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 fib6_nh_get_excptn_bucket+0x198/0x1b0 net/ipv6/route.c:1591 fib6_nh_flush_exceptions+0x37/0x2d0 net/ipv6/route.c:1719 fib6_nh_release+0x84/0x3a0 net/ipv6/route.c:3503 fib6_info_destroy_rcu+0x11e/0x150 net/ipv6/ip6_fib.c:174 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2114 [inline] rcu_core+0x67f/0x1580 kernel/rcu/tree.c:2314 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2323 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:537 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1133 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 RIP: 0010:__sanitizer_cov_trace_pc+0x1a/0x50 kernel/kcov.c:98 Code: 00 00 e9 77 e9 ff ff 90 90 90 90 90 90 90 90 90 55 48 89 e5 65 48 8b 04 25 40 fe 01 00 65 8b 15 a4 88 8f 7e 81 e2 00 01 1f 00 <48> 8b 75 08 75 2b 8b 90 f0 12 00 00 83 fa 02 75 20 48 8b 88 f8 12 RSP: 0018:ffff888047a5f720 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffff8880677ea340 RBX: 00007f695205d000 RCX: ffffffff819d3a24 RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000007 RBP: ffff888047a5f720 R08: ffff8880677ea340 R09: fffff9400050f037 R10: fffff9400050f036 R11: ffffea00028781b3 R12: ffffea00017eda00 R13: ffff888047a5fa00 R14: 01fffc0000000008 R15: dffffc0000000000 __read_once_size include/linux/compiler.h:199 [inline] compound_head include/linux/page-flags.h:174 [inline] PageSwapBacked include/linux/page-flags.h:340 [inline] mm_counter_file include/linux/mm.h:1692 [inline] mm_counter include/linux/mm.h:1701 [inline] zap_pte_range mm/memory.c:1058 [inline] zap_pmd_range mm/memory.c:1161 [inline] zap_pud_range mm/memory.c:1190 [inline] zap_p4d_range mm/memory.c:1211 [inline] unmap_page_range+0xc73/0x2170 mm/memory.c:1232 unmap_single_vma+0x19d/0x300 mm/memory.c:1277 unmap_vmas+0x135/0x280 mm/memory.c:1309 exit_mmap+0x2ba/0x530 mm/mmap.c:3145 __mmput kernel/fork.c:1064 [inline] mmput+0x179/0x4d0 kernel/fork.c:1085 exit_mm kernel/exit.c:547 [inline] do_exit+0x84e/0x2e50 kernel/exit.c:866 do_group_exit+0x135/0x360 kernel/exit.c:983 get_signal+0x47c/0x2500 kernel/signal.c:2734 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:159 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4598e9 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:00007f69507facf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000000 RBX: 000000000075bf28 RCX: 00000000004598e9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075bf28 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bf2c R13: 00007ffeb4c6634f R14: 00007f69507fb9c0 R15: 000000000075bf2c Allocated by task 6194: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:493 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:466 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:507 kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3550 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:748 [inline] fib6_info_alloc+0xb6/0x1b0 net/ipv6/ip6_fib.c:154 ip6_route_info_create+0x2fe/0x1530 net/ipv6/route.c:3605 ip6_route_add+0x27/0xc0 net/ipv6/route.c:3697 inet6_rtm_newroute+0x16c/0x180 net/ipv6/route.c:5265 rtnetlink_rcv_msg+0x463/0xb00 net/core/rtnetlink.c:5223 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5241 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x8a5/0xd60 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:657 ___sys_sendmsg+0x803/0x920 net/socket.c:2311 __sys_sendmsg+0x105/0x1d0 net/socket.c:2356 __do_sys_sendmsg net/socket.c:2365 [inline] __se_sys_sendmsg net/socket.c:2363 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2363 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 5688: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:455 kasan_slab_free+0xe/0x10 mm/kasan/common.c:463 __cache_free mm/slab.c:3425 [inline] kfree+0x10a/0x2c0 mm/slab.c:3756 ext4_swap_extents+0xa95/0x1520 fs/ext4/extents.c:5866 move_extent_per_page fs/ext4/move_extent.c:360 [inline] ext4_move_extents+0x20e7/0x4000 fs/ext4/move_extent.c:673 ext4_ioctl+0x3090/0x4120 fs/ext4/ioctl.c:924 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a8a4fb00 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 56 bytes to the right of 192-byte region [ffff8880a8a4fb00, ffff8880a8a4fbc0) The buggy address belongs to the page: page:ffffea0002a293c0 refcount:1 mapcount:0 mapping:ffff8880aa400000 index:0xffff8880a8a4f000 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea00025483c8 ffffea00027d0288 ffff8880aa400000 raw: ffff8880a8a4f000 ffff8880a8a4f000 000000010000000f 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a8a4fa80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8880a8a4fb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8880a8a4fb80: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880a8a4fc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a8a4fc80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================