==================================================================
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 ffff88812485f018 by task syz.4.134/889

CPU: 1 PID: 889 Comm: syz.4.134 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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_remove_space+0x2f0/0x4570 fs/ext4/extents.c:2829
 ext4_collapse_range fs/ext4/extents.c:5429 [inline]
 ext4_fallocate+0x1006/0x1a70 fs/ext4/extents.c:4769
 vfs_fallocate+0x4b4/0x590 fs/open.c:310
 ksys_fallocate fs/open.c:333 [inline]
 __do_sys_fallocate fs/open.c:341 [inline]
 __se_sys_fallocate fs/open.c:339 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:339
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7ff289ff3819
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:00007ff288a4e028 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007ff28a26cfa0 RCX: 00007ff289ff3819
RDX: 0000000000004000 RSI: 0000000000000008 RDI: 0000000000000009
RBP: 00007ff28a089c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000008000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff28a26d038 R14: 00007ff28a26cfa0 R15: 00007fff34169088

Allocated by task 0:
(stack is not available)

The buggy address belongs to the object at ffff88812485e000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 24 bytes to the right of
 4096-byte region [ffff88812485e000, ffff88812485f000)
The buggy address belongs to the page:
page:ffffea0004921600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x124858
head:ffffea0004921600 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 dead000000000100 dead000000000122 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 863, ts 48817570010, free_ts 48790196240
 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
 __devinet_sysctl_register+0xb6/0x3a0 net/ipv4/devinet.c:2586
 devinet_sysctl_register+0x169/0x1e0 net/ipv4/devinet.c:2638
 inetdev_init+0x273/0x480 net/ipv4/devinet.c:277
 inetdev_event+0x1f7/0x1040 net/ipv4/devinet.c:1544
 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
 register_vlan_dev+0x2ab/0x600 net/8021q/vlan.c:177
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 __free_pages_ok+0x80b/0x830 mm/page_alloc.c:1629
 free_the_page mm/page_alloc.c:5445 [inline]
 __free_pages+0xd8/0x3b0 mm/page_alloc.c:5454
 __free_slab+0xcf/0x190 mm/slub.c:1899
 free_slab mm/slub.c:1914 [inline]
 discard_slab mm/slub.c:1920 [inline]
 unfreeze_partials+0x15f/0x190 mm/slub.c:2415
 put_cpu_partial+0xc1/0x180 mm/slub.c:2451
 __slab_free+0x2c9/0x3a0 mm/slub.c:3100
 do_slab_free mm/slub.c:3196 [inline]
 ___cache_free+0x10e/0x130 mm/slub.c:3215
 qlink_free+0x50/0x90 mm/kasan/quarantine.c:157
 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x14a/0x160 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xf0 mm/kasan/common.c:440
 kasan_slab_alloc include/linux/kasan.h:244 [inline]
 slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:580
 slab_alloc_node mm/slub.c:2952 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 kmem_cache_alloc+0x162/0x2d0 mm/slub.c:2965
 sock_alloc_inode+0x1b/0xb0 net/socket.c:253
 alloc_inode fs/inode.c:233 [inline]
 new_inode_pseudo+0x62/0x210 fs/inode.c:968
 sock_alloc net/socket.c:574 [inline]
 __sock_create+0x12c/0x770 net/socket.c:1400

Memory state around the buggy address:
 ffff88812485ef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88812485ef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88812485f000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                            ^
 ffff88812485f080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88812485f100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
------------[ cut here ]------------
kernel BUG at fs/ext4/extents.c:3184!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 889 Comm: syz.4.134 Tainted: G    B             syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:ext4_split_extent_at+0xe1f/0xe40 fs/ext4/extents.c:3184
Code: a7 cf d2 ff e9 05 fc ff ff 89 d9 80 e1 07 fe c1 38 c1 0f 8c 12 fc ff ff 48 89 df e8 6b cf d2 ff e9 05 fc ff ff e8 81 4f 98 ff <0f> 0b e8 7a 4f 98 ff 0f 0b e8 73 4f 98 ff 0f 0b e8 6c 4f 98 ff 0f
RSP: 0018:ffffc90000dd79e0 EFLAGS: 00010293
RAX: ffffffff81cc63cf RBX: 1ffff11024916d83 RCX: ffff88811afe0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000030
RBP: ffffc90000dd7b30 R08: 0000000000000000 R09: 0000000050000028
R10: dffffc0000000000 R11: fffffbfff0dcf648 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007ff288a4e6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe98482fdc CR3: 0000000122ef1000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ext4_force_split_extent_at fs/ext4/extents.c:318 [inline]
 ext4_ext_remove_space+0x631/0x4570 fs/ext4/extents.c:2875
 ext4_collapse_range fs/ext4/extents.c:5429 [inline]
 ext4_fallocate+0x1006/0x1a70 fs/ext4/extents.c:4769
 vfs_fallocate+0x4b4/0x590 fs/open.c:310
 ksys_fallocate fs/open.c:333 [inline]
 __do_sys_fallocate fs/open.c:341 [inline]
 __se_sys_fallocate fs/open.c:339 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:339
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7ff289ff3819
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:00007ff288a4e028 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007ff28a26cfa0 RCX: 00007ff289ff3819
RDX: 0000000000004000 RSI: 0000000000000008 RDI: 0000000000000009
RBP: 00007ff28a089c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000008000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff28a26d038 R14: 00007ff28a26cfa0 R15: 00007fff34169088
Modules linked in:
---[ end trace e68211bf2158ab85 ]---
RIP: 0010:ext4_split_extent_at+0xe1f/0xe40 fs/ext4/extents.c:3184
Code: a7 cf d2 ff e9 05 fc ff ff 89 d9 80 e1 07 fe c1 38 c1 0f 8c 12 fc ff ff 48 89 df e8 6b cf d2 ff e9 05 fc ff ff e8 81 4f 98 ff <0f> 0b e8 7a 4f 98 ff 0f 0b e8 73 4f 98 ff 0f 0b e8 6c 4f 98 ff 0f
RSP: 0018:ffffc90000dd79e0 EFLAGS: 00010293
RAX: ffffffff81cc63cf RBX: 1ffff11024916d83 RCX: ffff88811afe0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000030
RBP: ffffc90000dd7b30 R08: 0000000000000000 R09: 0000000050000028
R10: dffffc0000000000 R11: fffffbfff0dcf648 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007ff288a4e6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9e7547fb45 CR3: 0000000122ef1000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400