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BUG: KASAN: use-after-free in sysv_new_inode+0xfd3/0x1170 fs/sysv/ialloc.c:153
Read of size 2 at addr ffff88804ea461ce by task syz.2.439/7900

CPU: 0 UID: 0 PID: 7900 Comm: syz.2.439 Not tainted 6.11.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 sysv_new_inode+0xfd3/0x1170 fs/sysv/ialloc.c:153
 sysv_mknod+0x4e/0xe0 fs/sysv/namei.c:53
 lookup_open fs/namei.c:3578 [inline]
 open_last_lookups fs/namei.c:3647 [inline]
 path_openat+0x1a9c/0x3470 fs/namei.c:3883
 do_filp_open+0x235/0x490 fs/namei.c:3913
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1416
 do_sys_open fs/open.c:1431 [inline]
 __do_sys_openat fs/open.c:1447 [inline]
 __se_sys_openat fs/open.c:1442 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1442
 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: 0033:0x7fc428579e79
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:00007fc4292e6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fc428715f80 RCX: 00007fc428579e79
RDX: 000000000000275a RSI: 0000000020000080 RDI: ffffffffffffff9c
RBP: 00007fc4285e793e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fc428715f80 R15: 00007ffe36773e08
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x22bb0 pfn:0x4ea46
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea00013a91c8 ffffea00013a9148 0000000000000000
raw: 0000000000022bb0 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 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 7900, tgid 7898 (syz.2.439), ts 441527873946, free_ts 728492496520
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1493
 prep_new_page mm/page_alloc.c:1501 [inline]
 get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3439
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4695
 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2263
 alloc_pages_noprof mm/mempolicy.c:2343 [inline]
 folio_alloc_noprof+0x128/0x180 mm/mempolicy.c:2350
 filemap_alloc_folio_noprof+0xdf/0x500 mm/filemap.c:1008
 do_read_cache_folio+0xed/0x820 mm/filemap.c:3753
 do_read_cache_page+0x30/0x200 mm/filemap.c:3855
 read_mapping_page include/linux/pagemap.h:907 [inline]
 dir_get_page fs/sysv/dir.c:64 [inline]
 sysv_find_entry+0x1af/0x410 fs/sysv/dir.c:157
 sysv_inode_by_name+0x98/0x1f0 fs/sysv/dir.c:374
 sysv_lookup+0x6b/0xe0 fs/sysv/namei.c:38
 lookup_open fs/namei.c:3556 [inline]
 open_last_lookups fs/namei.c:3647 [inline]
 path_openat+0x11ce/0x3470 fs/namei.c:3883
 do_filp_open+0x235/0x490 fs/namei.c:3913
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1416
 do_sys_open fs/open.c:1431 [inline]
 __do_sys_openat fs/open.c:1447 [inline]
 __se_sys_openat fs/open.c:1442 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1442
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
page last free pid 11543 tgid 11536 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1094 [inline]
 free_unref_folios+0x103a/0x1b00 mm/page_alloc.c:2660
 folios_put_refs+0x76e/0x860 mm/swap.c:1039
 folio_batch_release include/linux/pagevec.h:101 [inline]
 mapping_try_invalidate+0x3b1/0x4f0 mm/truncate.c:515
 drop_pagecache_sb+0x1bc/0x250 fs/drop_caches.c:40
 iterate_supers+0xc8/0x190 fs/super.c:934
 drop_caches_sysctl_handler+0x8c/0x160 fs/drop_caches.c:64
 proc_sys_call_handler+0x553/0x8b0 fs/proc/proc_sysctl.c:590
 iter_file_splice_write+0xbd9/0x14e0 fs/splice.c:743
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x120/0x220 fs/splice.c:1164
 splice_direct_to_actor+0x590/0xc90 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0x28c/0x3e0 fs/splice.c:1233
 do_sendfile+0x56d/0xe20 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1356 [inline]
 __se_sys_sendfile64+0x100/0x1e0 fs/read_write.c:1348
 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
page has been migrated, last migrate reason: compaction

Memory state around the buggy address:
 ffff88804ea46080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804ea46100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88804ea46180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff88804ea46200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804ea46280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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