loop4: detected capacity change from 0 to 1024
EXT4-fs: inline encryption not supported
==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_ext_correct_indexes+0x72/0x5b0 fs/ext4/extents.c:1712
Read of size 8 at addr ffff888037521050 by task syz.4.51/7020

CPU: 1 UID: 0 PID: 7020 Comm: syz.4.51 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/27/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_ext_correct_indexes+0x72/0x5b0 fs/ext4/extents.c:1712
 ext4_ext_insert_extent+0x2007/0x4b50 fs/ext4/extents.c:2191
 ext4_ext_map_blocks+0x1696/0x58b0 fs/ext4/extents.c:4457
 ext4_map_create_blocks+0x11d/0x540 fs/ext4/inode.c:616
 ext4_map_blocks+0x7cd/0x11d0 fs/ext4/inode.c:809
 _ext4_get_block+0x1e3/0x470 fs/ext4/inode.c:909
 ext4_get_block_unwritten+0x2e/0x100 fs/ext4/inode.c:942
 ext4_block_write_begin+0xb14/0x1950 fs/ext4/inode.c:1196
 ext4_write_begin+0xb40/0x18c0 fs/ext4/ext4_jbd2.h:-1
 ext4_da_write_begin+0x355/0xd90 fs/ext4/inode.c:3123
 generic_perform_write+0x2af/0x8b0 mm/filemap.c:4319
 ext4_buffered_write_iter+0xd0/0x3a0 fs/ext4/file.c:300
 ext4_file_write_iter+0x299/0x1c10 fs/ext4/file.c:-1
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x629/0xba0 fs/read_write.c:688
 ksys_pwrite64 fs/read_write.c:795 [inline]
 __do_sys_pwrite64 fs/read_write.c:803 [inline]
 __se_sys_pwrite64 fs/read_write.c:800 [inline]
 __x64_sys_pwrite64+0x19c/0x230 fs/read_write.c:800
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe19b45c629
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe19aab6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007fe19b6d5fa0 RCX: 00007fe19b45c629
RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000004
RBP: 00007fe19b4f2b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000c00 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe19b6d6038 R14: 00007fe19b6d5fa0 R15: 00007ffeb42afef8
 </TASK>

Allocated by task 64:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4542 [inline]
 slab_alloc_node mm/slub.c:4869 [inline]
 kmem_cache_alloc_noprof+0x33b/0x680 mm/slub.c:4876
 node_alloc net/ipv6/ip6_fib.c:188 [inline]
 fib6_add_1+0xa3a/0x1460 net/ipv6/ip6_fib.c:892
 fib6_add+0x211/0x18c0 net/ipv6/ip6_fib.c:1445
 __ip6_ins_rt net/ipv6/route.c:1352 [inline]
 ip6_ins_rt+0xed/0x160 net/ipv6/route.c:1362
 __ipv6_ifa_notify+0x4e8/0xc60 net/ipv6/addrconf.c:6287
 ipv6_ifa_notify net/ipv6/addrconf.c:6326 [inline]
 addrconf_dad_completed+0x1b5/0xe60 net/ipv6/addrconf.c:4324
 addrconf_dad_work+0xdc4/0x1680 include/linux/rwlock_rt.h:-1
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888037521000
 which belongs to the cache fib6_node of size 72
The buggy address is located 8 bytes to the right of
 allocated 72-byte region [ffff888037521000, ffff888037521048)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x37521
memcg:ffff888037521059
flags: 0x80000000000000(node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000000 ffff88814a047a00 dead000000000100 dead000000000122
raw: 0000000000000000 0000008000200020 00000000f5000000 ffff888037521059
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 64, tgid 64 (kworker/u8:4), ts 148854826065, free_ts 148851883973
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3296 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3485
 new_slab mm/slub.c:3543 [inline]
 refill_objects+0x334/0x3c0 mm/slub.c:7178
 __pcs_replace_empty_main+0x371/0x5c0 mm/slub.c:-1
 alloc_from_pcs mm/slub.c:4720 [inline]
 slab_alloc_node mm/slub.c:4854 [inline]
 kmem_cache_alloc_noprof+0x433/0x680 mm/slub.c:4876
 node_alloc net/ipv6/ip6_fib.c:188 [inline]
 fib6_add_1+0x9c1/0x1460 net/ipv6/ip6_fib.c:-1
 fib6_add+0x211/0x18c0 net/ipv6/ip6_fib.c:1445
 __ip6_ins_rt net/ipv6/route.c:1352 [inline]
 ip6_ins_rt+0xed/0x160 net/ipv6/route.c:1362
 __ipv6_ifa_notify+0x4e8/0xc60 net/ipv6/addrconf.c:6287
 ipv6_ifa_notify net/ipv6/addrconf.c:6326 [inline]
 addrconf_dad_completed+0x1b5/0xe60 net/ipv6/addrconf.c:4324
 addrconf_dad_work+0xdc4/0x1680 include/linux/rwlock_rt.h:-1
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:436
page last free pid 64 tgid 64 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xfe3/0x1170 mm/page_alloc.c:2978
 __slab_free+0x24f/0x2a0 mm/slub.c:5576
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4542 [inline]
 slab_alloc_node mm/slub.c:4869 [inline]
 kmem_cache_alloc_node_noprof+0x22a/0x6e0 mm/slub.c:4921
 __alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702
 alloc_skb include/linux/skbuff.h:1383 [inline]
 mld_newpack+0x14c/0xc90 net/ipv6/mcast.c:1775
 add_grhead+0x5a/0x2a0 net/ipv6/mcast.c:1886
 add_grec+0x1452/0x1740 net/ipv6/mcast.c:2025
 mld_send_initial_cr+0x288/0x550 net/ipv6/mcast.c:2268
 ipv6_mc_dad_complete+0x88/0x540 net/ipv6/mcast.c:2279
 addrconf_dad_completed+0x622/0xe60 net/ipv6/addrconf.c:4344
 addrconf_dad_work+0xdc4/0x1680 include/linux/rwlock_rt.h:-1
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439

Memory state around the buggy address:
 ffff888037520f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888037520f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888037521000: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
                                                 ^
 ffff888037521080: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
 ffff888037521100: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
==================================================================