loop0: detected capacity change from 0 to 128
VFS: Found a Xenix FS (block size = 1024) on device loop0
syz.0.0: attempt to access beyond end of device
loop0: rw=0, sector=6491536, nr_sectors = 2 limit=128
Buffer I/O error on dev loop0, logical block 3245768, async page read
==================================================================
BUG: KASAN: slab-out-of-bounds in sysv_new_block+0x790/0x970 fs/sysv/balloc.c:113
Read of size 4 at addr ffff888040cab0c8 by task syz.0.0/5329

CPU: 0 UID: 0 PID: 5329 Comm: syz.0.0 Not tainted 6.14.0-rc7-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0x16e/0x5b0 mm/kasan/report.c:521
 kasan_report+0x143/0x180 mm/kasan/report.c:634
 sysv_new_block+0x790/0x970 fs/sysv/balloc.c:113
 alloc_branch fs/sysv/itree.c:135 [inline]
 get_block+0x30a/0x16e0 fs/sysv/itree.c:254
 __block_write_begin_int+0x692/0x19a0 fs/buffer.c:2116
 block_write_begin+0x8f/0x120 fs/buffer.c:2226
 sysv_write_begin+0x31/0x70 fs/sysv/itree.c:490
 page_symlink+0x2c0/0x4d0 fs/namei.c:5436
 sysv_symlink+0xcf/0x180 fs/sysv/namei.c:86
 vfs_symlink+0x137/0x2e0 fs/namei.c:4671
 do_symlinkat+0x222/0x3a0 fs/namei.c:4697
 __do_sys_symlink fs/namei.c:4718 [inline]
 __se_sys_symlink fs/namei.c:4716 [inline]
 __x64_sys_symlink+0x7a/0x90 fs/namei.c:4716
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3e9c58d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3e989ef038 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00007f3e9c7a5fa0 RCX: 00007f3e9c58d169
RDX: 0000000000000000 RSI: 000040000000acc0 RDI: 000040000000ad80
RBP: 00007f3e9c60e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3e9c7a5fa0 R15: 00007fff5c1a3e48
 </TASK>

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4115 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4171
 __kernfs_new_node+0xd8/0x870 fs/kernfs/dir.c:624
 kernfs_new_node+0x137/0x240 fs/kernfs/dir.c:700
 __kernfs_create_file+0x49/0x2e0 fs/kernfs/file.c:1034
 sysfs_add_file_mode_ns+0x24a/0x310 fs/sysfs/file.c:313
 create_files fs/sysfs/group.c:76 [inline]
 internal_create_group+0x782/0x12d0 fs/sysfs/group.c:183
 internal_create_groups fs/sysfs/group.c:223 [inline]
 sysfs_create_groups+0x56/0x120 fs/sysfs/group.c:249
 create_dir lib/kobject.c:78 [inline]
 kobject_add_internal+0x472/0x8d0 lib/kobject.c:240
 kobject_add_varg lib/kobject.c:374 [inline]
 kobject_add+0x152/0x220 lib/kobject.c:426
 add_sysfs_fw_map_entry drivers/firmware/memmap.c:191 [inline]
 firmware_memmap_init+0x10f/0x1a0 drivers/firmware/memmap.c:414
 do_one_initcall+0x248/0x930 init/main.c:1257
 do_initcall_level+0x157/0x210 init/main.c:1319
 do_initcalls+0x71/0xd0 init/main.c:1335
 kernel_init_freeable+0x435/0x5d0 init/main.c:1568
 kernel_init+0x1d/0x2b0 init/main.c:1457
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The buggy address belongs to the object at ffff888040cab000
 which belongs to the cache kernfs_node_cache of size 176
The buggy address is located 24 bytes to the right of
 allocated 176-byte region [ffff888040cab000, ffff888040cab0b0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x40cab
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000000 ffff88801c6e4000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000110011 00000000f5000000 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 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1, tgid 1 (swapper/0), ts 21013153886, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1551
 prep_new_page mm/page_alloc.c:1559 [inline]
 get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3477
 __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4740
 alloc_pages_mpol+0x311/0x660 mm/mempolicy.c:2270
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab+0x8f/0x3a0 mm/slub.c:2587
 new_slab mm/slub.c:2640 [inline]
 ___slab_alloc+0xc27/0x14a0 mm/slub.c:3826
 __slab_alloc+0x58/0xa0 mm/slub.c:3916
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4171
 __kernfs_new_node+0xd8/0x870 fs/kernfs/dir.c:624
 kernfs_new_node+0x137/0x240 fs/kernfs/dir.c:700
 __kernfs_create_file+0x49/0x2e0 fs/kernfs/file.c:1034
 sysfs_add_file_mode_ns+0x24a/0x310 fs/sysfs/file.c:313
 create_files fs/sysfs/group.c:76 [inline]
 internal_create_group+0x782/0x12d0 fs/sysfs/group.c:183
 internal_create_groups fs/sysfs/group.c:223 [inline]
 sysfs_create_groups+0x56/0x120 fs/sysfs/group.c:249
 create_dir lib/kobject.c:78 [inline]
 kobject_add_internal+0x472/0x8d0 lib/kobject.c:240
 kobject_add_varg lib/kobject.c:374 [inline]
 kobject_add+0x152/0x220 lib/kobject.c:426
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888040caaf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888040cab000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888040cab080: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc 00 00
                                              ^
 ffff888040cab100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888040cab180: 00 00 00 00 fc fc fc fc fc fc fc fc 00 00 00 00
==================================================================