================================================================== BUG: KASAN: use-after-free in ext4_ext_rm_leaf fs/ext4/extents.c:2602 [inline] BUG: KASAN: use-after-free in ext4_ext_remove_space+0x2f43/0x3fb0 fs/ext4/extents.c:2940 Read of size 4 at addr ffff888126cc9db8 by task syz-executor/464 CPU: 0 PID: 464 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:88 dump_stack_lvl+0xee/0x150 lib/dump_stack.c:106 print_address_description+0x71/0x200 mm/kasan/report.c:316 print_report+0x4a/0x60 mm/kasan/report.c:420 kasan_report+0x122/0x150 mm/kasan/report.c:524 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:350 ext4_ext_rm_leaf fs/ext4/extents.c:2602 [inline] ext4_ext_remove_space+0x2f43/0x3fb0 fs/ext4/extents.c:2940 ext4_ext_truncate+0x200/0x320 fs/ext4/extents.c:4470 ext4_truncate+0x9a6/0xf90 fs/ext4/inode.c:4291 ext4_evict_inode+0xcc3/0x1460 fs/ext4/inode.c:286 evict+0x493/0x890 fs/inode.c:708 iput_final fs/inode.c:1844 [inline] iput+0x620/0x670 fs/inode.c:1870 do_unlinkat+0x375/0x6b0 fs/namei.c:4396 __do_sys_unlink fs/namei.c:4437 [inline] __se_sys_unlink fs/namei.c:4435 [inline] __x64_sys_unlink+0x49/0x50 fs/namei.c:4435 x64_sys_call+0x958/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:88 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f197cf8df57 Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 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:00007ffe2d43fdc8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f197cf8df57 RDX: 00007ffe2d43fdf0 RSI: 00007ffe2d43fe80 RDI: 00007ffe2d43fe80 RBP: 00007ffe2d43fe80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffe2d440f70 R13: 00007f197d010b55 R14: 000000000000ca94 R15: 00007ffe2d442040 The buggy address belongs to the physical page: page:ffffea00049b3240 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x126cc9 flags: 0x4000000000000000(zone=1) raw: 4000000000000000 dead000000000100 dead000000000122 0000000000000000 raw: 0000000000000001 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 0x8140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO|__GFP_CMA), pid 397, tgid 397 (syz-executor), ts 49406190578, free_ts 49454986638 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2643 prep_new_page+0x1c/0x110 mm/page_alloc.c:2650 get_page_from_freelist+0x2c7b/0x2cf0 mm/page_alloc.c:4554 __alloc_pages+0x1c3/0x450 mm/page_alloc.c:5868 __folio_alloc+0x12/0x40 mm/page_alloc.c:5900 __folio_alloc_node include/linux/gfp.h:245 [inline] folio_alloc include/linux/gfp.h:274 [inline] alloc_page_vma include/linux/gfp.h:283 [inline] do_anonymous_page mm/memory.c:4283 [inline] handle_pte_fault mm/memory.c:5169 [inline] __handle_mm_fault mm/memory.c:5313 [inline] handle_mm_fault+0x18ef/0x2640 mm/memory.c:5453 do_user_addr_fault+0x905/0x1050 arch/x86/mm/fault.c:1323 handle_page_fault arch/x86/mm/fault.c:1466 [inline] exc_page_fault+0x51/0xb0 arch/x86/mm/fault.c:1522 asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:608 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1551 [inline] free_pcp_prepare mm/page_alloc.c:1625 [inline] free_unref_page_prepare+0x742/0x750 mm/page_alloc.c:3589 free_unref_page_list+0x112/0x8b0 mm/page_alloc.c:3740 release_pages+0xad1/0xb20 mm/swap.c:1047 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:315 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline] tlb_flush_mmu_free mm/mmu_gather.c:254 [inline] tlb_flush_mmu mm/mmu_gather.c:261 [inline] tlb_finish_mmu+0x1aa/0x370 mm/mmu_gather.c:361 unmap_region+0x28d/0x2e0 mm/mmap.c:2418 do_mas_align_munmap+0xb9b/0x1230 mm/mmap.c:2691 do_mas_munmap+0x241/0x2b0 mm/mmap.c:2749 __vm_munmap+0x19f/0x2f0 mm/mmap.c:3048 __do_sys_munmap mm/mmap.c:3074 [inline] __se_sys_munmap mm/mmap.c:3070 [inline] __x64_sys_munmap+0x6b/0x80 mm/mmap.c:3070 x64_sys_call+0x8a/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:12 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Memory state around the buggy address: ffff888126cc9c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888126cc9d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff888126cc9d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888126cc9e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888126cc9e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 104953422308723, count = 30047 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 104953422308720, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 104863227283120, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 104863227274851, count = 8276 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 104863227274848, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 62012405172112, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 62012405145906, count = 26214 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 62012405145904, count = 16 EXT4-fs error: 24517 callbacks suppressed EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 35684306091904, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 35684306083679, count = 8240 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 35684306083664, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 112589232289894, count = 26214 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 112589232289888, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 129069982143184, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 129069982118770, count = 24421 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 129069982118768, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 109079828911504, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 109079828897840, count = 13666 EXT4-fs error: 27885 callbacks suppressed EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 55216945127984, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 122511365138896, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 122511365114487, count = 24421 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 122511365114480, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 113693712962768, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 113693712934252, count = 28532 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 113693712934240, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 35392416351104, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 35392416325716, count = 25393