================================================================== BUG: KASAN: use-after-free in ext4_ext_rm_leaf fs/ext4/extents.c:2601 [inline] BUG: KASAN: use-after-free in ext4_ext_remove_space+0x3496/0x40d0 fs/ext4/extents.c:2939 Read of size 4 at addr ffff88812cf99db8 by task syz-executor/363 CPU: 1 PID: 363 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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+0xf1/0x140 mm/kasan/report.c:444 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 ext4_ext_rm_leaf fs/ext4/extents.c:2601 [inline] ext4_ext_remove_space+0x3496/0x40d0 fs/ext4/extents.c:2939 ext4_ext_truncate+0x1a3/0x250 fs/ext4/extents.c:4473 ext4_truncate+0x9be/0xfb0 fs/ext4/inode.c:4287 ext4_evict_inode+0xcc5/0x1460 fs/ext4/inode.c:290 evict+0x4c9/0x8d0 fs/inode.c:650 iput_final fs/inode.c:1779 [inline] iput+0x635/0x7c0 fs/inode.c:1805 do_unlinkat+0x380/0x6d0 fs/namei.c:4363 __do_sys_unlink fs/namei.c:4404 [inline] __se_sys_unlink fs/namei.c:4402 [inline] __x64_sys_unlink+0x49/0x50 fs/namei.c:4402 x64_sys_call+0x878/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:88 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: 0033:0x7f36f157efa7 Code: 73 01 c3 48 c7 c1 e8 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 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007ffc64280cf8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f36f157efa7 RDX: 00007ffc64280d20 RSI: 00007ffc64280db0 RDI: 00007ffc64280db0 RBP: 00007ffc64280db0 R08: 00007ffc64281db0 R09: 00000000ffffffff R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffc64281ea0 R13: 00007f36f15e971f R14: 00000000000066a2 R15: 00007ffc64282f70 The buggy address belongs to the page: page:ffffea0004b3e640 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x12cf99 flags: 0x4000000000000000(zone=1) raw: 4000000000000000 ffffea0004b3e608 ffffea0004b3e688 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 0x100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), pid 297, ts 26303465721, free_ts 26304243188 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2605 prep_new_page+0x1c/0x110 mm/page_alloc.c:2611 get_page_from_freelist+0x2d3a/0x2dc0 mm/page_alloc.c:4485 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5808 __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] do_anonymous_page mm/memory.c:4069 [inline] handle_pte_fault+0xebf/0x2710 mm/memory.c:4909 __handle_mm_fault mm/memory.c:-1 [inline] do_handle_mm_fault+0x1af9/0x1de0 mm/memory.c:5333 handle_mm_fault include/linux/mm.h:1847 [inline] do_user_addr_fault+0x828/0x1250 arch/x86/mm/fault.c:1418 handle_page_fault arch/x86/mm/fault.c:1509 [inline] exc_page_fault+0x51/0xb0 arch/x86/mm/fault.c:1565 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:1472 [inline] free_pcp_prepare mm/page_alloc.c:1544 [inline] free_unref_page_prepare+0x542/0x550 mm/page_alloc.c:3534 free_unref_page_list+0x13a/0x9d0 mm/page_alloc.c:3671 release_pages+0x1006/0x1060 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 unmap_region+0x344/0x3b0 mm/mmap.c:2692 __do_munmap+0xa24/0x1020 mm/mmap.c:2925 __vm_munmap+0x163/0x2b0 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 Memory state around the buggy address: ffff88812cf99c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88812cf99d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88812cf99d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88812cf99e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88812cf99e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 192 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 2448131358720, count = 13888 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 37369408, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 37369408, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 687194767552, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 38764224, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 38764224, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 1 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 10485760, count = 192 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 265394619186998, count = 7456 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 845317632, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 845285080, count = 32566 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 845285072, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 266300857296000, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 266300857286454, count = 9552 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 266300857286448, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 2298856496, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 2298823936, count = 32566 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 2556944816, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 2556922944, count = 21875 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 167727062871888, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 167727062865267, count = 6624 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 167727062865264, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 2559284928, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 2559263056, count = 21875 EXT4-fs error (device loop2): ext4_free_blocks:6234: comm syz-executor: Freeing blocks not in datazone - block = 46656565601504, count = 16