================================================================== BUG: KASAN: use-after-free in ext4_ext_store_pblock fs/ext4/ext4_extents.h:256 [inline] BUG: KASAN: use-after-free in ext4_ext_rm_leaf fs/ext4/extents.c:2697 [inline] BUG: KASAN: use-after-free in ext4_ext_remove_space+0x28e0/0x40d0 fs/ext4/extents.c:2939 Write of size 4 at addr ffff888132c48e64 by task syz.5.38/630 CPU: 1 PID: 630 Comm: syz.5.38 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_store4_noabort+0x17/0x20 mm/kasan/report_generic.c:313 ext4_ext_store_pblock fs/ext4/ext4_extents.h:256 [inline] ext4_ext_rm_leaf fs/ext4/extents.c:2697 [inline] ext4_ext_remove_space+0x28e0/0x40d0 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_truncate_failed_write fs/ext4/truncate.h:22 [inline] ext4_write_begin+0xad4/0x12e0 fs/ext4/inode.c:1276 ext4_da_write_begin+0x321/0xbf0 fs/ext4/inode.c:2988 generic_perform_write+0x2b7/0x690 mm/filemap.c:3870 ext4_buffered_write_iter+0x4ed/0x670 fs/ext4/file.c:270 ext4_file_write_iter+0x440/0x1540 fs/ext4/file.c:-1 call_write_iter include/linux/fs.h:2212 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x835/0xfd0 fs/read_write.c:594 ksys_write+0x149/0x250 fs/read_write.c:647 __do_sys_write fs/read_write.c:659 [inline] __se_sys_write fs/read_write.c:656 [inline] __x64_sys_write+0x7b/0x90 fs/read_write.c:656 x64_sys_call+0x8ef/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2 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: 0033:0x7fd612ecd079 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:00007fd612912028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fd6130fa080 RCX: 00007fd612ecd079 RDX: 0000000000040010 RSI: 0000200000000180 RDI: 0000000000000006 RBP: 00007fd612f5fa4c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fd6130fa080 R15: 00007ffc6ac68e58 The buggy address belongs to the page: page:ffffea0004cb1200 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x132c48 flags: 0x4000000000000000(zone=1) raw: 4000000000000000 ffffea0004cb1248 ffffea0004cb11c8 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 613, ts 51134022740, free_ts 51287750717 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:1014 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+0x93/0x320 kernel/fork.c:1180 mmput+0x50/0x150 kernel/fork.c:1203 exit_mm kernel/exit.c:554 [inline] do_exit+0x9f2/0x27e0 kernel/exit.c:876 do_group_exit+0x141/0x310 kernel/exit.c:1003 get_signal+0x66a/0x1480 kernel/signal.c:2907 arch_do_signal_or_restart+0xdf/0x11c0 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: ffff888132c48d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888132c48d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff888132c48e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888132c48e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888132c48f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== EXT4-fs error (device loop5): ext4_free_blocks:6234: comm syz.5.38: Freeing blocks not in datazone - block = 73990787024039, count = 23085 EXT4-fs error (device loop5): ext4_free_blocks:6234: comm syz.5.38: Freeing blocks not in datazone - block = 97201896264569, count = 18835 EXT4-fs error (device loop5): ext4_free_blocks:6234: comm syz.5.38: Freeing blocks not in datazone - block = 208584865706138, count = 21227 EXT4-fs error (device loop5): ext4_free_blocks:6234: comm syz.5.38: Freeing blocks not in datazone - block = 163757749296904, count = 737 EXT4-fs error (device loop5): ext4_free_blocks:6234: comm syz.5.38: Freeing blocks not in datazone - block = 277445271591034, count = 3952 EXT4-fs error (device loop5): ext4_free_blocks:6234: comm syz.5.38: Freeing blocks not in datazone - block = 244440196204677, count = 14373 EXT4-fs error (device loop5): ext4_free_blocks:6234: comm syz.5.38: Freeing blocks not in datazone - block = 17862980922537, count = 5892 EXT4-fs error (device loop5): ext4_free_blocks:6234: comm syz.5.38: Freeing blocks not in datazone - block = 142142778190566, count = 22449