================================================================== BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:827 [inline] BUG: KASAN: use-after-free in ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:946 Read of size 4 at addr ffff88813bfaee18 by task kworker/u4:9/5943 CPU: 1 PID: 5943 Comm: kworker/u4:9 Not tainted 5.15.184-syzkaller-00129-g4032a894ccb2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: writeback wb_workfn (flush-7:6) Call Trace: __dump_stack+0x21/0x30 lib/dump_stack.c:88 dump_stack_lvl+0xee/0x150 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_binsearch fs/ext4/extents.c:827 [inline] ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:946 ext4_ext_map_blocks+0x1de/0x6270 fs/ext4/extents.c:4165 ext4_map_blocks+0x97b/0x1b20 fs/ext4/inode.c:674 mpage_map_one_extent fs/ext4/inode.c:2421 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2474 [inline] ext4_writepages+0x11e7/0x2f90 fs/ext4/inode.c:2842 do_writepages+0x48a/0x6c0 mm/page-writeback.c:2388 __writeback_single_inode+0xd5/0x9c0 fs/fs-writeback.c:1647 writeback_sb_inodes+0x9c0/0x1590 fs/fs-writeback.c:1930 wb_writeback+0x3f1/0x980 fs/fs-writeback.c:2106 wb_do_writeback fs/fs-writeback.c:2253 [inline] wb_workfn+0x38f/0xe20 fs/fs-writeback.c:2294 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 The buggy address belongs to the page: page:ffffea0004efeb80 refcount:0 mapcount:0 mapping:0000000000000000 index:0x100 pfn:0x13bfae flags: 0x4000000000000000(zone=1) raw: 4000000000000000 dead000000000100 dead000000000122 0000000000000000 raw: 0000000000000100 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 14906, ts 951117181461, free_ts 951902421491 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+0x2cc5/0x2d50 mm/page_alloc.c:4485 __alloc_pages+0x18f/0x440 mm/page_alloc.c:5781 __alloc_pages_node include/linux/gfp.h:591 [inline] alloc_pages_node include/linux/gfp.h:605 [inline] alloc_pages include/linux/gfp.h:618 [inline] shmem_alloc_page mm/shmem.c:1591 [inline] shmem_alloc_and_acct_page+0x42b/0x870 mm/shmem.c:1616 shmem_getpage_gfp+0xfe5/0x2310 mm/shmem.c:1912 shmem_fault+0x19d/0x510 mm/shmem.c:2124 __do_fault+0x264/0x2f0 mm/memory.c:4191 do_read_fault mm/memory.c:4555 [inline] do_fault mm/memory.c:4696 [inline] handle_pte_fault+0x1a57/0x2680 mm/memory.c:4910 __handle_mm_fault mm/memory.c:-1 [inline] do_handle_mm_fault+0x1a6d/0x1d50 mm/memory.c:5332 handle_mm_fault include/linux/mm.h:1836 [inline] faultin_page mm/gup.c:976 [inline] __get_user_pages+0x7ee/0x10a0 mm/gup.c:1197 populate_vma_page_range mm/gup.c:1529 [inline] __mm_populate+0x319/0x460 mm/gup.c:1638 mm_populate include/linux/mm.h:2693 [inline] vm_mmap_pgoff+0x247/0x410 mm/util.c:560 ksys_mmap_pgoff+0xf6/0x1d0 mm/mmap.c:1635 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:93 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:86 [inline] __x64_sys_mmap+0xfa/0x110 arch/x86/kernel/sys_x86_64.c:86 x64_sys_call+0x83/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:10 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+0x134/0x9d0 mm/page_alloc.c:3671 release_pages+0x1076/0x10d0 mm/swap.c:1009 __pagevec_release+0x71/0xe0 mm/swap.c:1029 pagevec_release include/linux/pagevec.h:81 [inline] shmem_undo_range+0x53f/0x13d0 mm/shmem.c:969 shmem_truncate_range mm/shmem.c:1068 [inline] shmem_evict_inode+0x1fd/0x9c0 mm/shmem.c:1150 evict+0x485/0x870 fs/inode.c:647 iput_final fs/inode.c:1769 [inline] iput+0x635/0x7c0 fs/inode.c:1795 dentry_unlink_inode+0x32f/0x3e0 fs/dcache.c:380 __dentry_kill+0x44f/0x650 fs/dcache.c:586 dentry_kill+0xc0/0x2a0 fs/dcache.c:-1 dput+0x47/0x90 fs/dcache.c:893 __fput+0x580/0x8b0 fs/file_table.c:319 ____fput+0x15/0x20 fs/file_table.c:339 task_work_run+0x127/0x190 kernel/task_work.c:188 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa76/0x27a0 kernel/exit.c:880 Memory state around the buggy address: ffff88813bfaed00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88813bfaed80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88813bfaee00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88813bfaee80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88813bfaef00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== EXT4-fs error (device loop6): ext4_ext_split:1074: inode #15: comm kworker/u4:9: p_ext > EXT_MAX_EXTENT! EXT4-fs (loop6): Delayed block allocation failed for inode 15 at logical offset 0 with max blocks 1 with error 117 EXT4-fs (loop6): This should not happen!! Data will be lost attempt to access beyond end of device loop6: rw=2049, want=40984, limit=40427