syz.3.6: attempt to access beyond end of device
loop3: rw=0, sector=6491536, nr_sectors = 2 limit=128
Buffer I/O error on dev loop3, logical block 3245768, async page read
unable to read i-node block
==================================================================
BUG: KASAN: use-after-free in sysv_new_block+0x788/0x960 fs/sysv/balloc.c:113
Read of size 4 at addr ffff8880719430c8 by task syz.3.6/4335

CPU: 0 PID: 4335 Comm: syz.3.6 Not tainted 6.1.128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:427
 kasan_report+0x136/0x160 mm/kasan/report.c:531
 sysv_new_block+0x788/0x960 fs/sysv/balloc.c:113
 alloc_branch fs/sysv/itree.c:134 [inline]
 get_block+0x2e7/0x1790 fs/sysv/itree.c:253
 __block_write_begin_int+0x544/0x1a30 fs/buffer.c:1991
 __block_write_begin fs/buffer.c:2041 [inline]
 block_write_begin+0x98/0x1f0 fs/buffer.c:2102
 sysv_write_begin+0x2d/0x60 fs/sysv/itree.c:487
 page_symlink+0x2c1/0x4e0 fs/namei.c:5218
 sysv_symlink+0xcb/0x180 fs/sysv/namei.c:86
 vfs_symlink+0x247/0x3d0 fs/namei.c:4471
 do_symlinkat+0x21e/0x390 fs/namei.c:4500
 __do_sys_symlink fs/namei.c:4522 [inline]
 __se_sys_symlink fs/namei.c:4520 [inline]
 __x64_sys_symlink+0x7a/0x90 fs/namei.c:4520
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f2a8f78cde9
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:00007f2a8f5ff038 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00007f2a8f9a5fa0 RCX: 00007f2a8f78cde9
RDX: 0000000000000000 RSI: 000040000000acc0 RDI: 000040000000ad80
RBP: 00007f2a8f80e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2a8f9a5fa0 R15: 00007ffc6ec7f368
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001c650c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x71943
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO), pid 4234, tgid 4234 (syz-executor), ts 56663341791, free_ts 59549406201
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x3731/0x38d0 mm/page_alloc.c:4328
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5605
 __folio_alloc+0xf/0x30 mm/page_alloc.c:5637
 vma_alloc_folio+0x486/0x990 mm/mempolicy.c:2243
 alloc_page_vma include/linux/gfp.h:284 [inline]
 do_anonymous_page mm/memory.c:4189 [inline]
 handle_pte_fault mm/memory.c:5027 [inline]
 __handle_mm_fault mm/memory.c:5171 [inline]
 handle_mm_fault+0x2e8e/0x5340 mm/memory.c:5292
 do_user_addr_fault arch/x86/mm/fault.c:1340 [inline]
 handle_page_fault arch/x86/mm/fault.c:1431 [inline]
 exc_page_fault+0x26f/0x620 arch/x86/mm/fault.c:1487
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x12a6/0x15b0 mm/page_alloc.c:3384
 free_unref_page_list+0x663/0x900 mm/page_alloc.c:3525
 release_pages+0x24c4/0x27a0 mm/swap.c:1035
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu+0xfc/0x210 mm/mmu_gather.c:261
 tlb_finish_mmu+0xce/0x1f0 mm/mmu_gather.c:361
 unmap_region+0x29f/0x2f0 mm/mmap.c:2331
 do_mas_align_munmap+0xef5/0x15a0 mm/mmap.c:2580
 do_mas_munmap+0x246/0x2b0 mm/mmap.c:2638
 __vm_munmap+0x268/0x370 mm/mmap.c:2924
 __do_sys_munmap mm/mmap.c:2949 [inline]
 __se_sys_munmap mm/mmap.c:2946 [inline]
 __x64_sys_munmap+0x5c/0x70 mm/mmap.c:2946
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff888071942f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888071943000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888071943080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff888071943100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888071943180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================