================================================================== BUG: KASAN: use-after-free in ptep_get include/linux/pgtable.h:461 [inline] BUG: KASAN: use-after-free in filemap_map_order0_folio mm/filemap.c:3856 [inline] BUG: KASAN: use-after-free in filemap_map_pages+0xc7a/0x2100 mm/filemap.c:3932 Read of size 8 at addr ffff88807bed6d50 by task syz.1.7707/30545 CPU: 1 UID: 0 PID: 30545 Comm: syz.1.7707 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 ptep_get include/linux/pgtable.h:461 [inline] filemap_map_order0_folio mm/filemap.c:3856 [inline] filemap_map_pages+0xc7a/0x2100 mm/filemap.c:3932 do_fault_around mm/memory.c:5867 [inline] do_read_fault mm/memory.c:5900 [inline] do_fault mm/memory.c:6043 [inline] do_pte_missing+0x1f38/0x33f0 mm/memory.c:4566 handle_pte_fault mm/memory.c:6427 [inline] __handle_mm_fault mm/memory.c:6565 [inline] handle_mm_fault+0x1bf2/0x3170 mm/memory.c:6734 do_user_addr_fault+0x75b/0x1340 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0010:rep_movs_alternative+0x30/0x90 arch/x86/lib/copy_user_64.S:60 Code: 83 f9 08 73 25 85 c9 74 0f 8a 06 88 07 48 ff c7 48 ff c6 48 ff c9 75 f1 c3 cc cc cc cc 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 db 83 f9 08 RSP: 0000:ffffc9000cb978b8 EFLAGS: 00050206 RAX: 00007ffffffff001 RBX: 000000000000001c RCX: 000000000000001c RDX: 0000000000000001 RSI: 00000000800bcae0 RDI: ffffc9000cb97940 RBP: ffffc9000cb979d0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52001972f2b R12: dffffc0000000000 R13: ffffc9000cb97c80 R14: ffffc9000cb97940 R15: 00000000800bcae0 copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:141 [inline] _inline_copy_from_user include/linux/uaccess.h:185 [inline] _copy_from_user+0x7a/0xb0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:223 [inline] get_compat_msghdr+0xb3/0x4c0 net/compat.c:91 recvmsg_copy_msghdr net/socket.c:2882 [inline] ___sys_recvmsg+0x1dd/0x590 net/socket.c:2956 do_recvmmsg+0x3a5/0x800 net/socket.c:3047 __sys_recvmmsg+0x1a5/0x290 net/socket.c:3129 __do_compat_sys_recvmmsg_time32 net/compat.c:418 [inline] __se_compat_sys_recvmmsg_time32 net/compat.c:414 [inline] __ia32_compat_sys_recvmmsg_time32+0xbf/0xe0 net/compat.c:414 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x229/0x6e0 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7fa501c Code: 90 85 d2 74 0a 89 ce 81 e6 ff 0f 00 00 89 32 85 c0 74 05 c1 e9 0c 89 08 31 c0 5e 5d c3 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 58 b8 RSP: 002b:00000000f544550c EFLAGS: 00000206 ORIG_RAX: 0000000000000151 RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00000000800000c0 RDX: 0000000000010106 RSI: 0000000000000002 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x121f pfn:0x7bed6 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f0(buddy) raw: 00fff00000000000 ffffea0000fea188 ffffea0002346808 0000000000000000 raw: 000000000000121f 0000000000000000 00000000f0000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 0, migratetype Unmovable, gfp_mask 0x140cc2(GFP_HIGHUSER|__GFP_COMP), pid 29415, tgid 29414 (syz.1.7355), ts 1634224509357, free_ts 1634614223058 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853 prep_new_page mm/page_alloc.c:1861 [inline] get_page_from_freelist+0x2593/0x2610 mm/page_alloc.c:3941 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221 alloc_pages_mpol+0x235/0x490 mm/mempolicy.c:2490 alloc_frozen_pages_noprof mm/mempolicy.c:2561 [inline] alloc_pages_noprof+0xac/0x2a0 mm/mempolicy.c:2581 folio_alloc_noprof+0x1e/0x30 mm/mempolicy.c:2591 filemap_alloc_folio_noprof+0x111/0x470 mm/filemap.c:1014 filemap_create_folio mm/filemap.c:2612 [inline] filemap_get_pages+0x819/0x1ef0 mm/filemap.c:2702 filemap_read+0x447/0x1230 mm/filemap.c:2806 __kernel_read+0x504/0x9b0 fs/read_write.c:532 integrity_kernel_read+0x89/0xd0 security/integrity/iint.c:28 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:222 [inline] ima_calc_file_hash+0x446/0x860 security/integrity/ima/ima_crypto.c:280 ima_collect_measurement+0x51d/0x9c0 security/integrity/ima/ima_api.c:300 process_measurement+0x12cd/0x1c80 security/integrity/ima/ima_main.c:425 ima_file_check+0xe1/0x130 security/integrity/ima/ima_main.c:685 security_file_post_open+0xb3/0x260 security/security.c:2755 page last free pid 29415 tgid 29414 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1397 [inline] free_unref_folios+0xd9f/0x14c0 mm/page_alloc.c:2999 folios_put_refs+0x9ff/0xb40 mm/swap.c:1008 folio_batch_release include/linux/folio_batch.h:101 [inline] truncate_inode_pages_range+0x3dd/0xe30 mm/truncate.c:408 evict+0x631/0xb10 fs/inode.c:843 __dentry_kill+0x1a2/0x690 fs/dcache.c:718 shrink_kill+0xa9/0x2c0 fs/dcache.c:1195 shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1222 shrink_dcache_tree+0xe9/0x5d0 fs/dcache.c:-1 do_one_tree fs/dcache.c:1721 [inline] shrink_dcache_for_umount+0xa8/0x1f0 fs/dcache.c:1738 generic_shutdown_super+0x6f/0x2d0 fs/super.c:624 kill_anon_super+0x3b/0x70 fs/super.c:1292 deactivate_locked_super+0xbc/0x130 fs/super.c:476 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x70f/0x22c0 kernel/exit.c:976 do_group_exit+0x21b/0x2d0 kernel/exit.c:1119 Memory state around the buggy address: ffff88807bed6c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88807bed6c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88807bed6d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88807bed6d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88807bed6e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== ---------------- Code disassembly (best guess): 0: 83 f9 08 cmp $0x8,%ecx 3: 73 25 jae 0x2a 5: 85 c9 test %ecx,%ecx 7: 74 0f je 0x18 9: 8a 06 mov (%rsi),%al b: 88 07 mov %al,(%rdi) d: 48 ff c7 inc %rdi 10: 48 ff c6 inc %rsi 13: 48 ff c9 dec %rcx 16: 75 f1 jne 0x9 18: c3 ret 19: cc int3 1a: cc int3 1b: cc int3 1c: cc int3 1d: 66 2e 0f 1f 84 00 00 cs nopw 0x0(%rax,%rax,1) 24: 00 00 00 27: 0f 1f 00 nopl (%rax) * 2a: 48 8b 06 mov (%rsi),%rax <-- trapping instruction 2d: 48 89 07 mov %rax,(%rdi) 30: 48 83 c6 08 add $0x8,%rsi 34: 48 83 c7 08 add $0x8,%rdi 38: 83 e9 08 sub $0x8,%ecx 3b: 74 db je 0x18 3d: 83 f9 08 cmp $0x8,%ecx