EXT4-fs error (device loop6): ext4_mb_release_inode_pa:4902: group 0, free 0, pa_free 1 ================================================================== 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 ffff8881396d1c18 by task syz.6.474/1546 CPU: 1 PID: 1546 Comm: syz.6.474 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 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:4479 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_pwrite64 fs/read_write.c:701 [inline] __do_sys_pwrite64 fs/read_write.c:711 [inline] __se_sys_pwrite64 fs/read_write.c:708 [inline] __x64_sys_pwrite64+0x197/0x220 fs/read_write.c:708 x64_sys_call+0xa6/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:19 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: 0033:0x7f682a90b799 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:00007f6829366028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 00007f682ab84fa0 RCX: 00007f682a90b799 RDX: 00000000200000c1 RSI: 00002000000000c0 RDI: 0000000000000008 RBP: 00007f682a9a1c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000009000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f682ab85038 R14: 00007f682ab84fa0 R15: 00007ffce78fde08 The buggy address belongs to the page: page:ffffea0004e5b440 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x1396d1 flags: 0x4000000000000000(zone=1) raw: 4000000000000000 ffffea0004e5b488 ffffea0004e5b408 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 1513, ts 80239707513, free_ts 80657380785 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:5822 __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] wp_page_copy+0x1de/0x1910 mm/memory.c:3221 do_wp_page+0x731/0xc90 mm/memory.c:-1 handle_pte_fault+0x762/0x2710 mm/memory.c:4932 __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:1416 handle_page_fault arch/x86/mm/fault.c:1507 [inline] exc_page_fault+0x51/0xb0 arch/x86/mm/fault.c:1560 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+0xdf/0x190 mm/mmu_gather.c:247 zap_pte_range mm/memory.c:1526 [inline] zap_pmd_range mm/memory.c:1575 [inline] zap_pud_range mm/memory.c:1604 [inline] zap_p4d_range mm/memory.c:1625 [inline] unmap_page_range+0x1bba/0x1d80 mm/memory.c:1646 unmap_single_vma mm/memory.c:1691 [inline] unmap_vmas+0x26d/0x380 mm/memory.c:1723 exit_mmap+0x412/0x8b0 mm/mmap.c:3245 __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 Memory state around the buggy address: ffff8881396d1b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881396d1b80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8881396d1c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8881396d1c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881396d1d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================