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BUG: KASAN: slab-out-of-bounds in instrument_copy_from_user_before include/linux/instrumented.h:129 [inline]
BUG: KASAN: slab-out-of-bounds in _copy_from_user+0x7b/0xe0 lib/usercopy.c:22
Write of size 20 at addr ffff88807648f5c8 by task syz-executor.1/10010

CPU: 1 PID: 10010 Comm: syz-executor.1 Not tainted 6.9.0-rc2-next-20240402-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
 instrument_copy_from_user_before include/linux/instrumented.h:129 [inline]
 _copy_from_user+0x7b/0xe0 lib/usercopy.c:22
 copy_from_user include/linux/uaccess.h:183 [inline]
 handle_to_path fs/fhandle.c:203 [inline]
 do_handle_open+0x204/0x660 fs/fhandle.c:226
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x72/0x7a
RIP: 0033:0x7f8fff67dde9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f90003110c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000130
RAX: ffffffffffffffda RBX: 00007f8fff7abf80 RCX: 00007f8fff67dde9
RDX: 00000000000a0000 RSI: 00000000200014c0 RDI: 0000000000000007
RBP: 00007f8fff6ca47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f8fff7abf80 R15: 00007ffdf5986518
 </TASK>

Allocated by task 10010:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slub.c:4048 [inline]
 __kmalloc_noprof+0x200/0x410 mm/slub.c:4061
 kmalloc_noprof include/linux/slab.h:664 [inline]
 handle_to_path fs/fhandle.c:195 [inline]
 do_handle_open+0x162/0x660 fs/fhandle.c:226
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x72/0x7a

The buggy address belongs to the object at ffff88807648f5c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 8 bytes inside of
 allocated 20-byte region [ffff88807648f5c0, ffff88807648f5d4)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7648f
flags: 0xfff80000000000(node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffefff(slab)
raw: 00fff80000000000 ffff888015041500 ffffea0000b36b00 dead000000000004
raw: 0000000000000000 0000000080400040 00000001ffffefff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 5099, tgid 545569792 (syz-executor.2), ts 5099, free_ts 64944698079
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1490
 prep_new_page mm/page_alloc.c:1498 [inline]
 get_page_from_freelist+0x2e7e/0x2f40 mm/page_alloc.c:3454
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4712
 __alloc_pages_node_noprof include/linux/gfp.h:244 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:271 [inline]
 alloc_slab_page+0x5f/0x120 mm/slub.c:2249
 allocate_slab+0x5a/0x2e0 mm/slub.c:2412
 new_slab mm/slub.c:2465 [inline]
 ___slab_alloc+0xea8/0x1430 mm/slub.c:3599
 __slab_alloc+0x58/0xa0 mm/slub.c:3684
 __slab_alloc_node mm/slub.c:3737 [inline]
 slab_alloc_node mm/slub.c:3915 [inline]
 kmalloc_trace_noprof+0x1d5/0x2b0 mm/slub.c:4074
 kmalloc_noprof include/linux/slab.h:660 [inline]
 kzalloc_noprof include/linux/slab.h:775 [inline]
 ref_tracker_alloc+0x14b/0x490 lib/ref_tracker.c:203
 __netdev_tracker_alloc include/linux/netdevice.h:4034 [inline]
 netdev_tracker_alloc include/linux/netdevice.h:4046 [inline]
 netdev_get_by_index+0x7a/0xb0 net/core/dev.c:911
 fib6_nh_init+0x1d8/0x2160 net/ipv6/route.c:3541
 ip6_route_info_create+0x99e/0x12b0 net/ipv6/route.c:3807
 ip6_route_add+0x28/0x160 net/ipv6/route.c:3851
 addrconf_prefix_route+0x314/0x4e0 net/ipv6/addrconf.c:2484
 inet6_addr_add+0x627/0xb00 net/ipv6/addrconf.c:3061
 inet6_rtm_newaddr+0x8a3/0xc80 net/ipv6/addrconf.c:5046
page last free pid 5141 tgid 5141 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1110 [inline]
 free_unref_page+0xd3c/0xec0 mm/page_alloc.c:2617
 discard_slab mm/slub.c:2511 [inline]
 __put_partials+0xeb/0x130 mm/slub.c:2980
 put_cpu_partial+0x17c/0x250 mm/slub.c:3055
 __slab_free+0x2ea/0x3d0 mm/slub.c:4233
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9e/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3867 [inline]
 slab_alloc_node mm/slub.c:3927 [inline]
 __do_kmalloc_node mm/slub.c:4047 [inline]
 __kmalloc_noprof+0x1a9/0x410 mm/slub.c:4061
 kmalloc_noprof include/linux/slab.h:664 [inline]
 kzalloc_noprof include/linux/slab.h:775 [inline]
 fib6_info_alloc+0x2e/0xf0 net/ipv6/ip6_fib.c:155
 ip6_route_info_create+0x445/0x12b0 net/ipv6/route.c:3759
 ip6_route_add+0x28/0x160 net/ipv6/route.c:3851
 addrconf_add_mroute net/ipv6/addrconf.c:2548 [inline]
 addrconf_add_dev+0x35b/0x540 net/ipv6/addrconf.c:2566
 addrconf_dev_config net/ipv6/addrconf.c:3480 [inline]
 addrconf_init_auto_addrs+0x85f/0xeb0 net/ipv6/addrconf.c:3568
 addrconf_notify+0xaff/0x1020 net/ipv6/addrconf.c:3741
 notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
 netdev_state_change+0x11f/0x1a0 net/core/dev.c:1358

Memory state around the buggy address:
 ffff88807648f480: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807648f500: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff88807648f580: 00 00 00 00 fc fc fc fc 00 00 04 fc fc fc fc fc
                                                 ^
 ffff88807648f600: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
 ffff88807648f680: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
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