================================================================== 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 ffff888127025db8 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: 0033:0x7f7eb4f8df57 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:00007ffc583e7248 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7eb4f8df57 RDX: 00007ffc583e7270 RSI: 00007ffc583e7300 RDI: 00007ffc583e7300 RBP: 00007ffc583e7300 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffc583e83f0 R13: 00007f7eb5010b55 R14: 000000000000c0d2 R15: 00007ffc583e94c0 The buggy address belongs to the physical page: page:ffffea00049c0940 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x127025 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 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 436, tgid 436 (syz-executor), ts 47702872949, free_ts 47748480365 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_cow_fault mm/memory.c:4761 [inline] do_fault+0x4c0/0x1df0 mm/memory.c:4877 handle_pte_fault mm/memory.c:5171 [inline] __handle_mm_fault mm/memory.c:5313 [inline] handle_mm_fault+0x12fa/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 exit_mmap+0x3dd/0xb60 mm/mmap.c:3382 __mmput+0x93/0x320 kernel/fork.c:1300 mmput+0x4b/0x150 kernel/fork.c:1323 exit_mm kernel/exit.c:568 [inline] do_exit+0x981/0x2650 kernel/exit.c:873 do_group_exit+0x210/0x2d0 kernel/exit.c:1028 get_signal+0x13b5/0x1520 kernel/signal.c:2889 arch_do_signal_or_restart+0xb0/0x1030 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x7a/0xb0 kernel/entry/common.c:174 exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 Memory state around the buggy address: ffff888127025c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888127025d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff888127025d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888127025e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888127025e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== EXT4-fs (loop2): unmounting filesystem. EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 111477745379024, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 111477745349744, count = 29285 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 111477745349744, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 104906496464064, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 104906496437865, count = 26211 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 104906496437856, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 62913220994400, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 62913220981552, count = 12849 EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 111576378429296, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 111576378402314, count = 26995 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 111576378402304, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 115879818810832, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 115879818782318, count = 28525 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 112382959524800, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 112382959510370, count = 14438 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 112382959510368, count = 16 EXT4-fs (loop2): unmounting filesystem. EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 281472911238992, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 281472911206228, count = 32767 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 281472911227120, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 281472911194362, count = 32767 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 281472911226112, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 281472911193359, count = 32767 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 281472911224976, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 281472911192222, count = 32767 EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 35578576, count = 0 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 1 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 0, count = 192 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 2388001816576, count = 20992 EXT4-fs (loop2): unmounting filesystem. EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 3038309664, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 3038277040, count = 32638 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 199114683903248, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 199114683875198, count = 28064 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 199114683875184, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 3038309632, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 3038277008, count = 32638 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 199114683903216, count = 16 EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs (loop2): unmounting filesystem. EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 112194853722576, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 112194853693030, count = 29550 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 112194853693024, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 132359859988400, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 132359859960415, count = 27999 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 132359859960400, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 111482023297760, count = 16 EXT4-fs error (device loop2): ext4_free_blocks:6205: comm syz-executor: Freeing blocks not in datazone - block = 111482023273331, count = 24435