Kernel bug: KASAN: out-of-bounds Read in ext4_xattr_set_entry
Subsystem: ext4
Status: open

Crash report:
==================================================================
BUG: KASAN: out-of-bounds in ext4_xattr_set_entry+0x8e9/0x1e20 fs/ext4/xattr.c:1782
Read of size 18446744073709551588 at addr ffff88807853c840 by task syz.0.59/6100

CPU: 0 UID: 0 PID: 6100 Comm: syz.0.59 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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+0x8e9/0x1e20 fs/ext4/xattr.c:1782
 ext4_xattr_block_set+0x872/0x2ac0 fs/ext4/xattr.c:2029
 ext4_xattr_set_handle+0x1350/0x1590 fs/ext4/xattr.c:2456
 ext4_xattr_set+0x230/0x320 fs/ext4/xattr.c:2558
 __vfs_setxattr+0x43c/0x480 fs/xattr.c:200
 __vfs_setxattr_noperm+0x12d/0x660 fs/xattr.c:234
 vfs_setxattr+0x16b/0x2f0 fs/xattr.c:321
 do_setxattr fs/xattr.c:636 [inline]
 filename_setxattr+0x274/0x600 fs/xattr.c:665
 path_setxattrat+0x364/0x3a0 fs/xattr.c:713
 __do_sys_lsetxattr fs/xattr.c:754 [inline]
 __se_sys_lsetxattr fs/xattr.c:750 [inline]
 __x64_sys_lsetxattr+0xbf/0xe0 fs/xattr.c:750
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f577478f749
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:00007ffd2c504408 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd
RAX: ffffffffffffffda RBX: 00007f57749e5fa0 RCX: 00007f577478f749
RDX: 0000200000000000 RSI: 0000200000000180 RDI: 00002000000001c0
RBP: 00007f5774813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000361 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f57749e5fa0 R14: 00007f57749e5fa0 R15: 0000000000000005
 </TASK>

Allocated by task 6100:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:397 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5657 [inline]
 __kmalloc_node_track_caller_noprof+0x575/0x820 mm/slub.c:5764
 kmemdup_noprof+0x2b/0x70 mm/util.c:138
 kmemdup_noprof include/linux/fortify-string.h:765 [inline]
 ext4_xattr_block_set+0x781/0x2ac0 fs/ext4/xattr.c:1977
 ext4_xattr_set_handle+0x1350/0x1590 fs/ext4/xattr.c:2456
 ext4_xattr_set+0x230/0x320 fs/ext4/xattr.c:2558
 __vfs_setxattr+0x43c/0x480 fs/xattr.c:200
 __vfs_setxattr_noperm+0x12d/0x660 fs/xattr.c:234
 vfs_setxattr+0x16b/0x2f0 fs/xattr.c:321
 do_setxattr fs/xattr.c:636 [inline]
 filename_setxattr+0x274/0x600 fs/xattr.c:665
 path_setxattrat+0x364/0x3a0 fs/xattr.c:713
 __do_sys_lsetxattr fs/xattr.c:754 [inline]
 __se_sys_lsetxattr fs/xattr.c:750 [inline]
 __x64_sys_lsetxattr+0xbf/0xe0 fs/xattr.c:750
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807853c800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 64 bytes inside of
 1024-byte region [ffff88807853c800, ffff88807853cc00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78538
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813ffa6dc0 0000000000000000 0000000000000001
raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ffa6dc0 0000000000000000 0000000000000001
head: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001e14e01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5567, tgid 5567 (rcS), ts 57940472272, free_ts 57924278459
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846
 prep_new_page mm/page_alloc.c:1854 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3075 [inline]
 allocate_slab+0x86/0x3b0 mm/slub.c:3248
 new_slab mm/slub.c:3302 [inline]
 ___slab_alloc+0xf2b/0x1960 mm/slub.c:4656
 __slab_alloc+0x65/0x100 mm/slub.c:4779
 __slab_alloc_node mm/slub.c:4855 [inline]
 slab_alloc_node mm/slub.c:5251 [inline]
 __do_kmalloc_node mm/slub.c:5656 [inline]
 __kmalloc_noprof+0x47d/0x800 mm/slub.c:5669
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 tomoyo_init_log+0x1a6e/0x1f70 security/tomoyo/audit.c:275
 tomoyo_supervisor+0x340/0x1480 security/tomoyo/common.c:2198
 tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline]
 tomoyo_env_perm+0x149/0x1e0 security/tomoyo/environ.c:63
 tomoyo_environ security/tomoyo/domain.c:672 [inline]
 tomoyo_find_next_domain+0x15ce/0x1aa0 security/tomoyo/domain.c:888
 tomoyo_bprm_check_security+0x11c/0x180 security/tomoyo/tomoyo.c:102
 security_bprm_check+0x89/0x270 security/security.c:794
 search_binary_handler fs/exec.c:1659 [inline]
 exec_binprm fs/exec.c:1701 [inline]
 bprm_execve+0x887/0x1400 fs/exec.c:1753
 do_execveat_common+0x510/0x6a0 fs/exec.c:1859
page last free pid 5488 tgid 5488 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_pages_ok+0xa83/0xbe0 mm/page_alloc.c:1571
 proc_sys_call_handler+0x571/0x700 fs/proc/proc_sysctl.c:612
 new_sync_read fs/read_write.c:491 [inline]
 vfs_read+0x55a/0xa30 fs/read_write.c:572
 ksys_read+0x145/0x250 fs/read_write.c:715
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88807853c700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88807853c780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88807853c800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                           ^
 ffff88807853c880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88807853c900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================