syzbot

unable to read i-node block
==================================================================
BUG: KASAN: use-after-free in sysv_new_block+0x790/0x970 fs/sysv/balloc.c:113
Read of size 4 at addr ffff88806d0bf0c8 by task syz-executor318/5901

CPU: 1 UID: 0 PID: 5901 Comm: syz-executor318 Not tainted 6.13.0-rc7-syzkaller-00019-gc45323b7560e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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:378 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:489
 kasan_report+0x143/0x180 mm/kasan/report.c:602
 sysv_new_block+0x790/0x970 fs/sysv/balloc.c:113
 alloc_branch fs/sysv/itree.c:135 [inline]
 get_block+0x30a/0x16d0 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+0x2a6/0x4a0 fs/namei.c:5416
 sysv_symlink+0xcf/0x180 fs/sysv/namei.c:86
 vfs_symlink+0x137/0x2e0 fs/namei.c:4669
 do_symlinkat+0x222/0x3a0 fs/namei.c:4695
 __do_sys_symlink fs/namei.c:4716 [inline]
 __se_sys_symlink fs/namei.c:4714 [inline]
 __x64_sys_symlink+0x7a/0x90 fs/namei.c:4714
 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: 0033:0x7fde099afea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 1f 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc0d483ca8 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fde099afea9
RDX: 0000000000000000 RSI: 00000000200059c0 RDI: 00000000200049c0
RBP: 00000000ffffffff R08: 0000000000009e7f R09: 00007fde099fd215
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc0d483d40
R13: 0000000000010000 R14: 0000000000000003 R15: 0000000000000000
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6d0bf
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001b40008 ffffea0001b42f88 0000000000000000
raw: 0000000000000000 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 0x8(__GFP_MOVABLE), pid 1, tgid 1 (swapper/0), ts 24937524040, free_ts 26309713995
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1558
 split_free_pages mm/page_alloc.c:6362 [inline]
 alloc_contig_range_noprof+0x821/0xe00 mm/page_alloc.c:6489
 __alloc_contig_pages mm/page_alloc.c:6518 [inline]
 alloc_contig_pages_noprof+0x4b3/0x5c0 mm/page_alloc.c:6598
 debug_vm_pgtable_alloc_huge_page+0xaf/0x100 mm/debug_vm_pgtable.c:1084
 init_args+0x83b/0xb20 mm/debug_vm_pgtable.c:1266
 debug_vm_pgtable+0xe0/0x550 mm/debug_vm_pgtable.c:1304
 do_one_initcall+0x248/0x870 init/main.c:1266
 do_initcall_level+0x157/0x210 init/main.c:1328
 do_initcalls+0x3f/0x80 init/main.c:1344
 kernel_init_freeable+0x435/0x5d0 init/main.c:1577
 kernel_init+0x1d/0x2b0 init/main.c:1466
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_page+0xd2c/0x1000 mm/page_alloc.c:2659
 free_contig_range+0x14c/0x430 mm/page_alloc.c:6632
 destroy_args+0x92/0x910 mm/debug_vm_pgtable.c:1017
 debug_vm_pgtable+0x4be/0x550 mm/debug_vm_pgtable.c:1397
 do_one_initcall+0x248/0x870 init/main.c:1266
 do_initcall_level+0x157/0x210 init/main.c:1328
 do_initcalls+0x3f/0x80 init/main.c:1344
 kernel_init_freeable+0x435/0x5d0 init/main.c:1577
 kernel_init+0x1d/0x2b0 init/main.c:1466
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Memory state around the buggy address:
 ffff88806d0bef80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806d0bf000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88806d0bf080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff88806d0bf100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806d0bf180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================