================================================================== BUG: KASAN: use-after-free in ext4_get_inode_usage+0x39c/0x520 fs/ext4/xattr.c:821 Read of size 4 at addr ffff88812e7de070 by task syz.6.31/445 CPU: 1 PID: 445 Comm: syz.6.31 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: 0033:0x7f8250d1ee59 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:00007f8250b81028 EFLAGS: 00000246 ORIG_RAX: 000000000000005e RAX: ffffffffffffffda RBX: 00007f8250f97fa0 RCX: 00007f8250d1ee59 RDX: 000000000000ee01 RSI: 0000000000000000 RDI: 00002000000006c0 RBP: 00007f8250db4e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8250f98038 R14: 00007f8250f97fa0 R15: 00007ffde8a181a8 Allocated by task 416: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:433 [inline] __kasan_slab_alloc+0xb7/0xe0 mm/kasan/common.c:466 kasan_slab_alloc include/linux/kasan.h:217 [inline] slab_post_alloc_hook+0x4f/0x2b0 mm/slab.h:550 slab_alloc_node mm/slub.c:3245 [inline] slab_alloc mm/slub.c:3255 [inline] kmem_cache_alloc+0xf7/0x260 mm/slub.c:3260 anon_vma_chain_alloc mm/rmap.c:141 [inline] anon_vma_clone+0xb7/0x4c0 mm/rmap.c:287 __split_vma+0x187/0x3e0 mm/mmap.c:2768 __do_munmap+0x3b4/0x1090 mm/mmap.c:2882 __vm_munmap+0x14e/0x280 mm/mmap.c:2978 __do_sys_munmap mm/mmap.c:3004 [inline] __se_sys_munmap mm/mmap.c:3000 [inline] __x64_sys_munmap+0x6b/0x80 mm/mmap.c:3000 x64_sys_call+0xc9/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:12 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 Freed by task 416: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4a/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:365 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373 kasan_slab_free include/linux/kasan.h:193 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1754 slab_free mm/slub.c:3526 [inline] kmem_cache_free+0x100/0x320 mm/slub.c:3544 anon_vma_chain_free mm/rmap.c:146 [inline] unlink_anon_vmas+0x2cb/0x590 mm/rmap.c:420 free_pgtables+0x7e/0x280 mm/memory.c:477 unmap_region+0x33c/0x3b0 mm/mmap.c:2690 __do_munmap+0xa99/0x1090 mm/mmap.c:2925 __vm_munmap+0x14e/0x280 mm/mmap.c:2978 __do_sys_munmap mm/mmap.c:3004 [inline] __se_sys_munmap mm/mmap.c:3000 [inline] __x64_sys_munmap+0x6b/0x80 mm/mmap.c:3000 x64_sys_call+0xc9/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:12 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 The buggy address belongs to the object at ffff88812e7de060 which belongs to the cache anon_vma_chain of size 64 The buggy address is located 16 bytes inside of 64-byte region [ffff88812e7de060, ffff88812e7de0a0) The buggy address belongs to the page: page:ffffea0004b9f780 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12e7de flags: 0x4000000000000200(slab|zone=1) raw: 4000000000000200 0000000000000000 dead000000000122 ffff888100187380 raw: 0000000000000000 00000000002a002a 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 416, ts 33583392957, free_ts 33582696369 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_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1937 [inline] new_slab+0xa0/0x4d0 mm/slub.c:2000 ___slab_alloc+0x3ac/0x840 mm/slub.c:3033 __slab_alloc+0x49/0x90 mm/slub.c:3120 slab_alloc_node mm/slub.c:3211 [inline] slab_alloc mm/slub.c:3255 [inline] kmem_cache_alloc+0x138/0x260 mm/slub.c:3260 anon_vma_chain_alloc mm/rmap.c:141 [inline] __anon_vma_prepare+0x56/0x420 mm/rmap.c:195 do_anonymous_page mm/memory.c:4069 [inline] handle_pte_fault+0x1ff1/0x2770 mm/memory.c:4921 __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] do_user_addr_fault+0x808/0x11c0 arch/x86/mm/fault.c:1416 handle_page_fault arch/x86/mm/fault.c:1507 [inline] exc_page_fault+0x51/0xb0 arch/x86/mm/fault.c:1560 asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:606 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: ffff88812e7ddf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88812e7ddf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88812e7de000: fa fb fb fb fb fb fb fb fc fc fc fc fa fb fb fb ^ ffff88812e7de080: fb fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb ffff88812e7de100: fc fc fc fc fa fb fb fb fb fb fb fb fc fc fc fc ==================================================================