================================================================== BUG: KASAN: use-after-free in filemap_fault+0x25f5/0x2a00 mm/filemap.c:2559 Read of size 8 at addr ffff8880a4f3a358 by task syz-executor2/21571 CPU: 0 PID: 21571 Comm: syz-executor2 Not tainted 4.20.0-next-20190107 #6 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 filemap_fault+0x25f5/0x2a00 mm/filemap.c:2559 __do_fault+0x176/0x7b0 mm/memory.c:3013 do_read_fault mm/memory.c:3424 [inline] do_fault mm/memory.c:3550 [inline] handle_pte_fault mm/memory.c:3781 [inline] __handle_mm_fault+0x370a/0x55a0 mm/memory.c:3905 handle_mm_fault+0x4ec/0xc80 mm/memory.c:3942 do_user_addr_fault arch/x86/mm/fault.c:1475 [inline] __do_page_fault+0x5da/0xd60 arch/x86/mm/fault.c:1541 do_page_fault+0xe6/0x7d8 arch/x86/mm/fault.c:1572 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1143 RIP: 0010:do_strncpy_from_user lib/strncpy_from_user.c:45 [inline] RIP: 0010:strncpy_from_user+0x2ba/0x4e0 lib/strncpy_from_user.c:118 Code: 08 bf 07 00 00 00 49 83 c5 08 48 89 de e8 ae d5 dd fd 48 83 fb 07 0f 86 75 01 00 00 e8 ff d3 dd fd 48 8b 85 70 ff ff ff 31 f6 <4e> 8b 34 28 31 ff 89 b5 5c ff ff ff e8 65 d5 dd fd 8b b5 5c ff ff RSP: 0018:ffff888059977c30 EFLAGS: 00010246 RAX: 00000000200000c0 RBX: 0000000000000fe0 RCX: ffffc90009e0b000 RDX: 00000000000001ee RSI: 0000000000000000 RDI: 0000000000000007 RBP: ffff888059977ce8 R08: ffff88805df92600 R09: ffff88821bc49080 R10: 000000000000001c R11: ffff888050af793f R12: ffff888050af6960 R13: 0000000000000000 R14: ffff888059977cc0 R15: dffffc0000000000 getname_flags fs/namei.c:151 [inline] getname_flags+0x11b/0x5b0 fs/namei.c:129 getname+0x1a/0x20 fs/namei.c:211 do_sys_open+0x3a5/0x7c0 fs/open.c:1057 __do_sys_openat fs/open.c:1090 [inline] __se_sys_openat fs/open.c:1084 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1084 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f68f234ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457ec9 RDX: 0000000000000000 RSI: 00000000200000c0 RDI: ffffffffffffff9c RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f68f234b6d4 R13: 00000000004c3fe9 R14: 00000000004d7150 R15: 00000000ffffffff Allocated by task 21571: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] kasan_kmalloc mm/kasan/common.c:482 [inline] kasan_kmalloc+0xcf/0xe0 mm/kasan/common.c:455 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:397 kmem_cache_alloc+0x12d/0x710 mm/slab.c:3541 vm_area_alloc+0x7a/0x1d0 kernel/fork.c:331 mmap_region+0x93b/0x1ca0 mm/mmap.c:1756 do_mmap+0xa09/0x1220 mm/mmap.c:1559 do_mmap_pgoff include/linux/mm.h:2421 [inline] vm_mmap_pgoff+0x20b/0x2b0 mm/util.c:350 ksys_mmap_pgoff+0x4f8/0x650 mm/mmap.c:1609 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 21584: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:444 kasan_slab_free+0xe/0x10 mm/kasan/common.c:452 __cache_free mm/slab.c:3485 [inline] kmem_cache_free+0x86/0x260 mm/slab.c:3747 vm_area_free+0x1d/0x30 kernel/fork.c:350 remove_vma+0x142/0x180 mm/mmap.c:185 remove_vma_list mm/mmap.c:2585 [inline] __do_munmap+0x72e/0xef0 mm/mmap.c:2828 do_munmap mm/mmap.c:2836 [inline] mmap_region+0x698/0x1ca0 mm/mmap.c:1729 do_mmap+0xa09/0x1220 mm/mmap.c:1559 do_mmap_pgoff include/linux/mm.h:2421 [inline] vm_mmap_pgoff+0x20b/0x2b0 mm/util.c:350 ksys_mmap_pgoff+0x4f8/0x650 mm/mmap.c:1609 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a4f3a318 which belongs to the cache vm_area_struct(49:syz2) of size 200 The buggy address is located 64 bytes inside of 200-byte region [ffff8880a4f3a318, ffff8880a4f3a3e0) The buggy address belongs to the page: page:ffffea000293ce80 count:1 mapcount:0 mapping:ffff888099652080 index:0xffff8880a4f3ae70 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea000230a6c8 ffffea00028235c8 ffff888099652080 raw: ffff8880a4f3ae70 ffff8880a4f3a000 000000010000000e ffff8880597f8bc0 page dumped because: kasan: bad access detected page->mem_cgroup:ffff8880597f8bc0 Memory state around the buggy address: ffff8880a4f3a200: fc fc fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a4f3a280: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc >ffff8880a4f3a300: fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a4f3a380: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8880a4f3a400: fc fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================