================================================================== BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:837 [inline] BUG: KASAN: use-after-free in ext4_find_extent+0xbc8/0xde0 fs/ext4/extents.c:953 Read of size 4 at addr ffff88804617ce2c by task syz-executor.4/11152 CPU: 1 PID: 11152 Comm: syz-executor.4 Not tainted 6.5.0-rc3-syzkaller-00123-g57012c57536f #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0x163/0x540 mm/kasan/report.c:475 kasan_report+0x175/0x1b0 mm/kasan/report.c:588 ext4_ext_binsearch fs/ext4/extents.c:837 [inline] ext4_find_extent+0xbc8/0xde0 fs/ext4/extents.c:953 ext4_ext_map_blocks+0x2d1/0x71d0 fs/ext4/extents.c:4101 ext4_map_blocks+0xa2f/0x1cb0 fs/ext4/inode.c:621 _ext4_get_block+0x238/0x6a0 fs/ext4/inode.c:763 __block_write_begin_int+0x555/0x1a60 fs/buffer.c:2128 block_page_mkwrite+0x29d/0x4e0 fs/buffer.c:2651 ext4_page_mkwrite+0x500/0x1290 fs/ext4/inode.c:6116 do_page_mkwrite+0x1a4/0x600 mm/memory.c:2942 wp_page_shared mm/memory.c:3294 [inline] do_wp_page+0x559/0x3a70 mm/memory.c:3376 handle_pte_fault mm/memory.c:4955 [inline] __handle_mm_fault mm/memory.c:5079 [inline] handle_mm_fault+0x1c58/0x5410 mm/memory.c:5233 do_user_addr_fault arch/x86/mm/fault.c:1392 [inline] handle_page_fault arch/x86/mm/fault.c:1486 [inline] exc_page_fault+0x266/0x7c0 arch/x86/mm/fault.c:1542 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570 RIP: 0010:rep_movs_alternative+0x4a/0xb0 arch/x86/lib/copy_user_64.S:71 Code: 75 f1 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb c9 a4 c3 0f 1f 00 4c 8b 06 4c 8b 4e 08 4c 8b 56 10 4c 8b 5e 18 4c RSP: 0018:ffffc90008e17918 EFLAGS: 00050206 RAX: ffffffff8434c201 RBX: 0000000020000a00 RCX: 0000000000000a00 RDX: 0000000000000000 RSI: ffff888046796600 RDI: 0000000020001000 RBP: ffffc90008e17a78 R08: ffff888046796fff R09: 1ffff11008cf2dff R10: dffffc0000000000 R11: ffffed1008cf2e00 R12: 1ffff920011c2fb3 R13: ffff888046796000 R14: 0000000000001000 R15: ffffc90008e17d98 copy_user_generic arch/x86/include/asm/uaccess_64.h:112 [inline] raw_copy_to_user arch/x86/include/asm/uaccess_64.h:133 [inline] copyout lib/iov_iter.c:168 [inline] _copy_to_iter+0x241/0x1000 lib/iov_iter.c:316 copy_page_to_iter+0xb1/0x160 lib/iov_iter.c:481 copy_folio_to_iter include/linux/uio.h:185 [inline] filemap_read+0x86b/0x10d0 mm/filemap.c:2709 call_read_iter include/linux/fs.h:1865 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x795/0xb00 fs/read_write.c:470 ksys_read+0x1a0/0x2c0 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fd1b747cb29 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd1b81de0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fd1b759bf80 RCX: 00007fd1b747cb29 RDX: 000000000000ffd2 RSI: 0000000020000a00 RDI: 0000000000000006 RBP: 00007fd1b74c847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fd1b759bf80 R15: 00007ffe696b61e8 The buggy address belongs to the physical page: page:ffffea0001185f00 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x1 pfn:0x4617c flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffff7f(buddy) raw: 00fff00000000000 ffffea0001079a08 ffffea0001887608 0000000000000000 raw: 0000000000000001 0000000000000001 00000000ffffff7f 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 11044, tgid 11040 (syz-executor.1), ts 413831057263, free_ts 415831234467 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1e6/0x210 mm/page_alloc.c:1570 prep_new_page mm/page_alloc.c:1577 [inline] get_page_from_freelist+0x31e8/0x3370 mm/page_alloc.c:3221 __alloc_pages+0x255/0x670 mm/page_alloc.c:4477 __folio_alloc+0x13/0x30 mm/page_alloc.c:4509 vma_alloc_folio+0x48a/0x9a0 mm/mempolicy.c:2240 shmem_alloc_folio mm/shmem.c:1579 [inline] shmem_alloc_and_acct_folio+0x5e7/0xe10 mm/shmem.c:1603 shmem_get_folio_gfp+0x120f/0x3470 mm/shmem.c:1948 shmem_get_folio mm/shmem.c:2079 [inline] shmem_write_begin+0x172/0x4e0 mm/shmem.c:2573 generic_perform_write+0x31b/0x630 mm/filemap.c:3923 generic_file_write_iter+0xaf/0x310 mm/filemap.c:4044 call_write_iter include/linux/fs.h:1871 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x782/0xaf0 fs/read_write.c:584 ksys_write+0x1a0/0x2c0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1161 [inline] free_unref_page_prepare+0x903/0xa30 mm/page_alloc.c:2348 free_unref_page_list+0x596/0x830 mm/page_alloc.c:2489 release_pages+0x2193/0x2470 mm/swap.c:1042 __folio_batch_release+0x84/0x100 mm/swap.c:1062 folio_batch_release include/linux/pagevec.h:83 [inline] shmem_undo_range+0x6af/0x1ba0 mm/shmem.c:954 shmem_truncate_range mm/shmem.c:1049 [inline] shmem_evict_inode+0x258/0x9f0 mm/shmem.c:1164 evict+0x2a4/0x620 fs/inode.c:665 __dentry_kill+0x436/0x650 fs/dcache.c:607 dentry_kill+0xbb/0x290 dput+0x1f3/0x420 fs/dcache.c:913 __fput+0x628/0x950 fs/file_table.c:392 task_work_run+0x24a/0x300 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xd9/0x100 kernel/entry/common.c:171 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x64/0x280 kernel/entry/common.c:297 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86 Memory state around the buggy address: ffff88804617cd00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88804617cd80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88804617ce00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88804617ce80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88804617cf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== ---------------- Code disassembly (best guess): 0: 75 f1 jne 0xfffffff3 2: c3 ret 3: 66 2e 0f 1f 84 00 00 cs nopw 0x0(%rax,%rax,1) a: 00 00 00 d: 0f 1f 00 nopl (%rax) 10: 48 8b 06 mov (%rsi),%rax 13: 48 89 07 mov %rax,(%rdi) 16: 48 83 c6 08 add $0x8,%rsi 1a: 48 83 c7 08 add $0x8,%rdi 1e: 83 e9 08 sub $0x8,%ecx 21: 74 df je 0x2 23: 83 f9 08 cmp $0x8,%ecx 26: 73 e8 jae 0x10 28: eb c9 jmp 0xfffffff3 * 2a: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction 2c: c3 ret 2d: 0f 1f 00 nopl (%rax) 30: 4c 8b 06 mov (%rsi),%r8 33: 4c 8b 4e 08 mov 0x8(%rsi),%r9 37: 4c 8b 56 10 mov 0x10(%rsi),%r10 3b: 4c 8b 5e 18 mov 0x18(%rsi),%r11 3f: 4c rex.WR