==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_ext_binsearch fs/ext4/extents.c:827 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:946
Read of size 4 at addr ffff88812901e20c by task kworker/u4:0/8

CPU: 1 PID: 8 Comm: kworker/u4:0 Not tainted 5.15.189-syzkaller-00079-ga71626bd56a5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: writeback wb_workfn (flush-7:3)
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0xee/0x150 lib/dump_stack.c:106
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0xf1/0x140 mm/kasan/report.c:444
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_ext_binsearch fs/ext4/extents.c:827 [inline]
 ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:946
 ext4_ext_map_blocks+0x1de/0x6280 fs/ext4/extents.c:4166
 ext4_map_blocks+0x97b/0x1b20 fs/ext4/inode.c:674
 mpage_map_one_extent fs/ext4/inode.c:2421 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2474 [inline]
 ext4_writepages+0x11e7/0x2f90 fs/ext4/inode.c:2842
 do_writepages+0x48a/0x6c0 mm/page-writeback.c:2388
 __writeback_single_inode+0xd5/0x9c0 fs/fs-writeback.c:1647
 writeback_sb_inodes+0x9c0/0x1590 fs/fs-writeback.c:1930
 wb_writeback+0x3f1/0x980 fs/fs-writeback.c:2106
 wb_do_writeback fs/fs-writeback.c:2253 [inline]
 wb_workfn+0x38f/0xe20 fs/fs-writeback.c:2294
 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325
 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472
 kthread+0x411/0x500 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Allocated by task 0:
(stack is not available)

The buggy address belongs to the object at ffff88812901e118
 which belongs to the cache ext4_groupinfo_2k of size 212
The buggy address is located 32 bytes to the right of
 212-byte region [ffff88812901e118, ffff88812901e1ec)
The buggy address belongs to the page:
page:ffffea0004a40780 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12901e
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 0000000000000000 dead000000000122 ffff8881267e6180
raw: 0000000000000000 00000000800e000e 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Reclaimable, gfp_mask 0x112c50(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 387, ts 22626302726, free_ts 0
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2605
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2611
 get_page_from_freelist+0x2cc5/0x2d50 mm/page_alloc.c:4485
 __alloc_pages+0x18f/0x440 mm/page_alloc.c:5795
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1932 [inline]
 new_slab+0xa1/0x4d0 mm/slub.c:1995
 ___slab_alloc+0x381/0x810 mm/slub.c:3028
 __slab_alloc+0x49/0x90 mm/slub.c:3115
 slab_alloc_node mm/slub.c:3206 [inline]
 slab_alloc mm/slub.c:3250 [inline]
 kmem_cache_alloc+0x138/0x260 mm/slub.c:3255
 kmem_cache_zalloc include/linux/slab.h:737 [inline]
 ext4_mb_add_groupinfo+0x2ea/0x8f0 fs/ext4/mballoc.c:3202
 ext4_mb_init_backend fs/ext4/mballoc.c:3281 [inline]
 ext4_mb_init+0x1397/0x2100 fs/ext4/mballoc.c:3561
 ext4_fill_super+0x78f9/0x9030 fs/ext4/super.c:4883
 mount_bdev+0x2ae/0x3e0 fs/super.c:1400
 ext4_mount+0x34/0x40 fs/ext4/super.c:6621
 legacy_get_tree+0xed/0x190 fs/fs_context.c:611
 vfs_get_tree+0x89/0x260 fs/super.c:1530
 do_new_mount+0x25a/0xa20 fs/namespace.c:3014
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88812901e100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88812901e180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88812901e200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                      ^
 ffff88812901e280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88812901e300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
------------[ cut here ]------------
kernel BUG at fs/ext4/inode.c:2433!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 8 Comm: kworker/u4:0 Tainted: G    B             5.15.189-syzkaller-00079-ga71626bd56a5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: writeback wb_workfn (flush-7:3)
RIP: 0010:mpage_map_one_extent fs/ext4/inode.c:2433 [inline]
RIP: 0010:mpage_map_and_submit_extent fs/ext4/inode.c:2474 [inline]
RIP: 0010:ext4_writepages+0x2eed/0x2f90 fs/ext4/inode.c:2842
Code: 00 74 08 48 89 df e8 22 01 ce ff 48 8b 3b 48 8b 74 24 28 48 8b 54 24 30 44 89 e9 45 89 f0 e8 6a 9b 07 00 eb 51 e8 a3 88 8f ff <0f> 0b e8 9c 88 8f ff eb 2f e8 95 88 8f ff eb 5f e8 8e 88 8f ff 31
RSP: 0018:ffffc90000087100 EFLAGS: 00010293
RAX: ffffffff81d9272d RBX: ffff88811298c778 RCX: ffff888100270000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000087470 R08: dffffc0000000000 R09: ffffed10225318e8
R10: ffffed10225318e8 R11: 1ffff110225318e7 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f16d10d1000 CR3: 000000010da09000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 do_writepages+0x48a/0x6c0 mm/page-writeback.c:2388
 __writeback_single_inode+0xd5/0x9c0 fs/fs-writeback.c:1647
 writeback_sb_inodes+0x9c0/0x1590 fs/fs-writeback.c:1930
 wb_writeback+0x3f1/0x980 fs/fs-writeback.c:2106
 wb_do_writeback fs/fs-writeback.c:2253 [inline]
 wb_workfn+0x38f/0xe20 fs/fs-writeback.c:2294
 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325
 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472
 kthread+0x411/0x500 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Modules linked in:
---[ end trace c3c91efbe8f954b7 ]---
RIP: 0010:mpage_map_one_extent fs/ext4/inode.c:2433 [inline]
RIP: 0010:mpage_map_and_submit_extent fs/ext4/inode.c:2474 [inline]
RIP: 0010:ext4_writepages+0x2eed/0x2f90 fs/ext4/inode.c:2842
Code: 00 74 08 48 89 df e8 22 01 ce ff 48 8b 3b 48 8b 74 24 28 48 8b 54 24 30 44 89 e9 45 89 f0 e8 6a 9b 07 00 eb 51 e8 a3 88 8f ff <0f> 0b e8 9c 88 8f ff eb 2f e8 95 88 8f ff eb 5f e8 8e 88 8f ff 31
RSP: 0018:ffffc90000087100 EFLAGS: 00010293
RAX: ffffffff81d9272d RBX: ffff88811298c778 RCX: ffff888100270000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000087470 R08: dffffc0000000000 R09: ffffed10225318e8
R10: ffffed10225318e8 R11: 1ffff110225318e7 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9defbe1178 CR3: 000000011dc1a000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000004 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400