==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_ext_binsearch fs/ext4/extents.c:826 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:945
Read of size 4 at addr ffff888126abb408 by task kworker/u4:1/9

CPU: 1 PID: 9 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: writeback wb_workfn (flush-7:5)
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0xe2/0x130 mm/kasan/report.c:452
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_ext_binsearch fs/ext4/extents.c:826 [inline]
 ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:945
 ext4_ext_map_blocks+0x20b/0x5dd0 fs/ext4/extents.c:4166
 ext4_map_blocks+0x985/0x1bd0 fs/ext4/inode.c:674
 mpage_map_one_extent fs/ext4/inode.c:2452 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2505 [inline]
 ext4_writepages+0x136a/0x2eb0 fs/ext4/inode.c:2873
 do_writepages+0x128/0x280 mm/page-writeback.c:2380
 __writeback_single_inode+0xd5/0xa20 fs/fs-writeback.c:1470
 writeback_sb_inodes+0x8ca/0x1480 fs/fs-writeback.c:1733
 wb_writeback+0x403/0xbe0 fs/fs-writeback.c:1908
 wb_do_writeback fs/fs-writeback.c:2053 [inline]
 wb_workfn+0x3ac/0xf30 fs/fs-writeback.c:2094
 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301
 worker_thread+0xa6a/0x13c0 kernel/workqueue.c:2447
 kthread+0x346/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Allocated by task 0:
(stack is not available)

The buggy address belongs to the object at ffff888126aba000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 1032 bytes to the right of
 4096-byte region [ffff888126aba000, ffff888126abb000)
The buggy address belongs to the page:
page:ffffea00049aae00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x126ab8
head:ffffea00049aae00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 0000000000000000 0000000300000001 ffff888100042c00
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 277, ts 26185546537, free_ts 0
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x179/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x223b/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x290/0x620 mm/page_alloc.c:5384
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1813 [inline]
 new_slab+0x84/0x3f0 mm/slub.c:1874
 new_slab_objects mm/slub.c:2632 [inline]
 ___slab_alloc+0x2a6/0x450 mm/slub.c:2796
 __slab_alloc+0x63/0xa0 mm/slub.c:2836
 slab_alloc_node mm/slub.c:2918 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 __kmalloc_track_caller+0x1ec/0x320 mm/slub.c:4541
 kmemdup+0x26/0x60 mm/util.c:131
 __addrconf_sysctl_register+0xb6/0x3e0 net/ipv6/addrconf.c:7046
 addrconf_sysctl_register+0x147/0x1a0 net/ipv6/addrconf.c:7111
 ipv6_add_dev+0xbaf/0x10a0 net/ipv6/addrconf.c:450
 addrconf_notify+0x582/0xe90 net/ipv6/addrconf.c:3571
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:410
 call_netdevice_notifiers_info net/core/dev.c:2054 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2066 [inline]
 call_netdevice_notifiers+0x119/0x190 net/core/dev.c:2080
 register_netdevice+0x1056/0x13e0 net/core/dev.c:10100
 __ip_tunnel_create+0x2c7/0x390 net/ipv4/ip_tunnel.c:267
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888126abb300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888126abb380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888126abb400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                      ^
 ffff888126abb480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888126abb500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
EXT4-fs error (device loop5): __ext4_get_inode_loc:4444: comm kworker/u4:1: Invalid inode table block 18444644534781477013 in block_group 0
EXT4-fs error (device loop5) in ext4_reserve_inode_write:5952: Corrupt filesystem
EXT4-fs error (device loop5): ext4_dirty_inode:6162: inode #15: comm kworker/u4:1: mark_inode_dirty error
EXT4-fs error (device loop5): __ext4_get_inode_loc:4444: comm kworker/u4:1: Invalid inode table block 18444644534781477013 in block_group 0
EXT4-fs error (device loop5) in ext4_reserve_inode_write:5952: Corrupt filesystem
EXT4-fs error (device loop5): ext4_dirty_inode:6162: inode #15: comm kworker/u4:1: mark_inode_dirty error
EXT4-fs (loop5): Delayed block allocation failed for inode 15 at logical offset 47 with max blocks 1 with error 117
EXT4-fs (loop5): This should not happen!! Data will be lost