================================================================== BUG: KASAN: use-after-free in ext4_ext_rm_leaf fs/ext4/extents.c:2596 [inline] BUG: KASAN: use-after-free in ext4_ext_remove_space+0x374f/0x4570 fs/ext4/extents.c:2934 Read of size 4 at addr ffff888121dd5c18 by task syz-executor/486 CPU: 0 PID: 486 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+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0xe2/0x130 mm/kasan/report.c:452 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 ext4_ext_rm_leaf fs/ext4/extents.c:2596 [inline] ext4_ext_remove_space+0x374f/0x4570 fs/ext4/extents.c:2934 ext4_ext_truncate+0x169/0x1f0 fs/ext4/extents.c:4467 ext4_truncate+0xb21/0x12d0 fs/ext4/inode.c:4373 ext4_evict_inode+0xf5b/0x1770 fs/ext4/inode.c:290 evict+0x4ae/0x930 fs/inode.c:612 iput_final fs/inode.c:1736 [inline] iput+0x638/0x7c0 fs/inode.c:1762 do_unlinkat+0x347/0x680 fs/namei.c:4050 __do_sys_unlink fs/namei.c:4090 [inline] __se_sys_unlink fs/namei.c:4088 [inline] __x64_sys_unlink+0x49/0x50 fs/namei.c:4088 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fe68ca92fa7 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:00007fffc164a168 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe68ca92fa7 RDX: 00007fffc164a190 RSI: 00007fffc164a220 RDI: 00007fffc164a220 RBP: 00007fffc164a220 R08: 00007fffc164b220 R09: 00000000ffffffff R10: 0000000000000100 R11: 0000000000000206 R12: 00007fffc164b310 R13: 00007fe68cafd71f R14: 000000000000b04f R15: 00007fffc164c3e0 The buggy address belongs to the page: page:ffffea0004877540 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x121dd5 flags: 0x4000000000000000() raw: 4000000000000000 ffffea0004877588 ffffea0004877508 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 0x100cca(GFP_HIGHUSER_MOVABLE), pid 482, ts 44565974283, free_ts 44701904412 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x179/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x223b/0x23d0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x290/0x620 mm/page_alloc.c:5370 __alloc_pages include/linux/gfp.h:544 [inline] __alloc_pages_node include/linux/gfp.h:557 [inline] alloc_pages_node include/linux/gfp.h:571 [inline] alloc_pages include/linux/gfp.h:590 [inline] do_cow_fault mm/memory.c:4418 [inline] do_fault mm/memory.c:4529 [inline] handle_pte_fault+0xf53/0x3750 mm/memory.c:4791 __handle_mm_fault mm/memory.c:4944 [inline] handle_mm_fault+0xf81/0x1710 mm/memory.c:5358 do_user_addr_fault+0x5a8/0xc90 arch/x86/mm/fault.c:1362 handle_page_fault arch/x86/mm/fault.c:1428 [inline] exc_page_fault+0x5a/0xc0 arch/x86/mm/fault.c:1484 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:571 page last free stack trace: reset_page_owner include/linux/page_owner.h:28 [inline] free_pages_prepare mm/page_alloc.c:1349 [inline] free_pcp_prepare mm/page_alloc.c:1421 [inline] free_unref_page_prepare+0x2b7/0x2d0 mm/page_alloc.c:3336 free_unref_page_list+0x129/0x9c0 mm/page_alloc.c:3443 release_pages+0xe52/0xea0 mm/swap.c:1103 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:356 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:326 exit_mmap+0x329/0x590 mm/mmap.c:3387 __mmput+0x93/0x2f0 kernel/fork.c:1153 mmput+0x4e/0x150 kernel/fork.c:1176 exit_mm kernel/exit.c:539 [inline] do_exit+0x9ec/0x2500 kernel/exit.c:859 do_group_exit+0x141/0x310 kernel/exit.c:986 get_signal+0xf7d/0x12e0 kernel/signal.c:2793 arch_do_signal_or_restart+0xe2/0x11d0 arch/x86/kernel/signal.c:805 handle_signal_work kernel/entry/common.c:145 [inline] exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56 Memory state around the buggy address: ffff888121dd5b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888121dd5b80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff888121dd5c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888121dd5c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888121dd5d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 281472864432208, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 281472864399451, count = 32767 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 281472864432208, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 281472864399451, count = 32767 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 281472864432128, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 281472864399373, count = 32767 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 281472855951840, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 281472855919082, count = 32767 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 281472855948096, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 3, count = 8 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 1 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 32736, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 32742 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 104863294718416, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 104863294710131, count = 8292 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 104863294710128, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 62012405422992, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 62012405396790, count = 26214 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 62012405396784, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 51073168087968, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 51073168062004, count = 25973 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 51073168062000, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 29758864, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 77370369081968, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 77370369069405, count = 12570 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 129108428903632, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 129108428878693, count = 24950 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 129108428878688, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 130220882908848, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 130220882883423, count = 25439 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 130220882883408, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 107148536169152, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 107148536144750, count = 24415 EXT4-fs error (device loop2): ext4_free_blocks:5701: comm syz-executor: Freeing blocks not in datazone - block = 59607220711312, count = 16