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BUG: KASAN: out-of-bounds in ext4_xattr_set_entry+0x9c1/0x1e20 fs/ext4/xattr.c:1756
Read of size 18446744073709551600 at addr ffff88804210a124 by task syz.0.0/5322

CPU: 0 UID: 0 PID: 5322 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
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_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:200
 __asan_memmove+0x29/0x70 mm/kasan/shadow.c:94
 ext4_xattr_set_entry+0x9c1/0x1e20 fs/ext4/xattr.c:1756
 ext4_xattr_ibody_set+0x254/0x6a0 fs/ext4/xattr.c:2268
 ext4_destroy_inline_data_nolock+0x214/0x5b0 fs/ext4/inline.c:463
 ext4_destroy_inline_data+0x83/0xe0 fs/ext4/inline.c:1788
 ext4_do_writepages+0x526/0x4610 fs/ext4/inode.c:2810
 ext4_writepages+0x205/0x350 fs/ext4/inode.c:3025
 do_writepages+0x32e/0x550 mm/page-writeback.c:2604
 filemap_fdatawrite_wbc mm/filemap.c:389 [inline]
 __filemap_fdatawrite_range mm/filemap.c:422 [inline]
 __filemap_fdatawrite mm/filemap.c:428 [inline]
 filemap_flush+0x191/0x230 mm/filemap.c:473
 ext4_release_file+0x82/0x310 fs/ext4/file.c:169
 __fput+0x44c/0xa70 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f127018f749
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:00007ffd2e3724b8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00000000000137c5 RCX: 00007f127018f749
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f12703e7da0 R08: 0000000000000001 R09: 0000000b2e3727af
R10: 00007f126ffff02c R11: 0000000000000246 R12: 00007f12703e5fac
R13: 00007f12703e5fa0 R14: ffffffffffffffff R15: 00007ffd2e3725d0
 </TASK>

The buggy address belongs to the physical page:
page: refcount:2 mapcount:0 mapping:ffff88803234cd80 index:0x3 pfn:0x4210a
memcg:ffff888030ad8d00
aops:def_blk_aops ino:700000 dentry name(?):""
flags: 0x4fff5800000423c(referenced|uptodate|dirty|lru|workingset|private|node=1|zone=1|lastcpupid=0x7ff)
raw: 04fff5800000423c ffffea00010f2208 ffff888030ae8a80 ffff88803234cd80
raw: 0000000000000003 ffff8880320fce80 00000002ffffffff ffff888030ad8d00
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x140cc0(GFP_USER|__GFP_COMP), pid 5323, tgid 5322 (syz.0.0), ts 80309715043, free_ts 80303811691
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845
 prep_new_page mm/page_alloc.c:1853 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3879
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 alloc_frozen_pages_noprof mm/mempolicy.c:2487 [inline]
 alloc_pages_noprof+0xa9/0x190 mm/mempolicy.c:2507
 folio_alloc_noprof+0x1e/0x30 mm/mempolicy.c:2517
 filemap_alloc_folio_noprof+0xdf/0x470 mm/filemap.c:1020
 do_read_cache_folio+0x2da/0x590 mm/filemap.c:3998
 read_mapping_folio include/linux/pagemap.h:999 [inline]
 read_part_sector+0xb6/0x2b0 block/partitions/core.c:722
 ultrix_partition+0xab/0x8b0 block/partitions/ultrix.c:29
 check_partition block/partitions/core.c:141 [inline]
 blk_add_partitions block/partitions/core.c:589 [inline]
 bdev_disk_changed+0x75f/0x14b0 block/partitions/core.c:693
 loop_reread_partitions drivers/block/loop.c:449 [inline]
 loop_set_status+0x918/0xd60 drivers/block/loop.c:1278
 lo_ioctl+0x9ef/0x1c50 drivers/block/loop.c:-1
 blkdev_ioctl+0x5af/0x6d0 block/ioctl.c:705
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
page last free pid 5330 tgid 5330 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2901
 discard_slab mm/slub.c:3330 [inline]
 __put_partials+0x146/0x170 mm/slub.c:3876
 put_cpu_partial+0x1f2/0x2e0 mm/slub.c:3951
 __slab_free+0x2b9/0x390 mm/slub.c:5929
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4978 [inline]
 slab_alloc_node mm/slub.c:5288 [inline]
 __do_kmalloc_node mm/slub.c:5649 [inline]
 __kmalloc_noprof+0x3c3/0x7f0 mm/slub.c:5662
 kmalloc_noprof include/linux/slab.h:961 [inline]
 tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x213/0x4b0 security/tomoyo/file.c:822
 security_file_truncate+0xb1/0x270 security/security.c:3215
 handle_truncate fs/namei.c:3594 [inline]
 do_open fs/namei.c:3979 [inline]
 path_openat+0x3022/0x3830 fs/namei.c:4134
 do_filp_open+0x1fa/0x410 fs/namei.c:4161
 do_sys_openat2+0x121/0x1c0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94

Memory state around the buggy address:
 ffff88804210a000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804210a080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88804210a100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                               ^
 ffff88804210a180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804210a200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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