================================================================== BUG: KASAN: use-after-free in ext4_get_inode_usage+0x39c/0x520 fs/ext4/xattr.c:821 Read of size 4 at addr ffff8881305b4070 by task syz.1.95/640 CPU: 0 PID: 640 Comm: syz.1.95 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: __dump_stack+0x21/0x30 lib/dump_stack.c:88 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:427 [inline] kasan_report+0x10f/0x150 mm/kasan/report.c:444 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 ext4_get_inode_usage+0x39c/0x520 fs/ext4/xattr.c:821 __dquot_transfer+0x192/0x22d0 fs/quota/dquot.c:2015 dquot_transfer+0x2f3/0x470 fs/quota/dquot.c:2167 ext4_setattr+0x746/0x1b10 fs/ext4/inode.c:5508 notify_change+0xc30/0xf40 fs/attr.c:505 chown_common+0x4b4/0x680 fs/open.c:681 do_fchownat+0x147/0x240 fs/open.c:712 __do_sys_lchown fs/open.c:737 [inline] __se_sys_lchown fs/open.c:735 [inline] __x64_sys_lchown+0x85/0x90 fs/open.c:735 x64_sys_call+0x171/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:95 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fc4f8932e59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fc4f8795028 EFLAGS: 00000246 ORIG_RAX: 000000000000005e RAX: ffffffffffffffda RBX: 00007fc4f8babfa0 RCX: 00007fc4f8932e59 RDX: 000000000000ee01 RSI: 0000000000000000 RDI: 00002000000006c0 RBP: 00007fc4f89c8e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc4f8bac038 R14: 00007fc4f8babfa0 R15: 00007fff6f806868 The buggy address belongs to the page: page:ffffea0004c16d00 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1305b4 flags: 0x4000000000000000(zone=1) raw: 4000000000000000 ffffea0004c16ec8 ffffea0004379788 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 Unmovable, gfp_mask 0x500dc0(GFP_USER|__GFP_ZERO|__GFP_ACCOUNT), pid 534, ts 33862945595, free_ts 33918007561 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2607 prep_new_page+0x1c/0x110 mm/page_alloc.c:2613 get_page_from_freelist+0x2c3a/0x2cd0 mm/page_alloc.c:4487 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5824 __alloc_pages_node include/linux/gfp.h:595 [inline] alloc_pages_node include/linux/gfp.h:609 [inline] alloc_pages include/linux/gfp.h:622 [inline] __pte_alloc_one include/asm-generic/pgalloc.h:63 [inline] pte_alloc_one+0x70/0x190 arch/x86/mm/pgtable.c:33 do_fault_around mm/memory.c:4519 [inline] do_read_fault mm/memory.c:4561 [inline] do_fault mm/memory.c:4709 [inline] handle_pte_fault+0x19d0/0x2770 mm/memory.c:4923 __handle_mm_fault mm/memory.c:-1 [inline] do_handle_mm_fault+0x1b3b/0x1e30 mm/memory.c:5345 handle_mm_fault include/linux/mm.h:1847 [inline] faultin_page mm/gup.c:976 [inline] __get_user_pages+0x80e/0x10c0 mm/gup.c:1197 populate_vma_page_range mm/gup.c:1529 [inline] __mm_populate+0x324/0x470 mm/gup.c:1638 mm_populate include/linux/mm.h:2704 [inline] vm_mmap_pgoff+0x245/0x410 mm/util.c:560 ksys_mmap_pgoff+0x161/0x1d0 mm/mmap.c:1647 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:93 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:86 [inline] __x64_sys_mmap+0xfa/0x110 arch/x86/kernel/sys_x86_64.c:86 x64_sys_call+0x83/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:10 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1474 [inline] free_pcp_prepare mm/page_alloc.c:1546 [inline] free_unref_page_prepare+0x5fa/0x600 mm/page_alloc.c:3536 free_unref_page_list+0x138/0x9e0 mm/page_alloc.c:3673 release_pages+0x1264/0x12c0 mm/swap.c:1015 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:320 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] tlb_flush_mmu_free mm/mmu_gather.c:240 [inline] tlb_flush_mmu mm/mmu_gather.c:247 [inline] tlb_finish_mmu+0x17e/0x310 mm/mmu_gather.c:338 exit_mmap+0x43b/0x8b0 mm/mmap.c:3248 __mmput+0x92/0x300 kernel/fork.c:1185 mmput+0x50/0x150 kernel/fork.c:1208 exit_mm kernel/exit.c:555 [inline] do_exit+0xacc/0x29a0 kernel/exit.c:877 do_group_exit+0x149/0x310 kernel/exit.c:1004 get_signal+0x64f/0x1430 kernel/signal.c:2907 arch_do_signal_or_restart+0xe2/0x1100 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0xa7/0xe0 kernel/entry/common.c:178 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 Memory state around the buggy address: ffff8881305b3f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8881305b3f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8881305b4000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8881305b4080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881305b4100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================