================================================================== BUG: KASAN: use-after-free in filemap_fault+0x25f5/0x2a00 mm/filemap.c:2559 Read of size 8 at addr ffff888096a35da8 by task syz-executor0/25560 CPU: 0 PID: 25560 Comm: syz-executor0 Not tainted 4.20.0-next-20190103 #5 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 ext4_filemap_fault+0x83/0xaf fs/ext4/inode.c:6327 __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:__get_user_4+0x21/0x30 arch/x86/lib/getuser.S:78 Code: 50 ff 31 c0 0f 1f 00 c3 90 48 83 c0 03 72 55 65 48 8b 14 25 40 ee 01 00 48 3b 82 18 14 00 00 73 43 48 19 d2 48 21 d0 0f 1f 00 <8b> 50 fd 31 c0 0f 1f 00 c3 66 0f 1f 44 00 00 48 83 c0 07 72 25 65 RSP: 0018:ffff88803e98fbc0 EFLAGS: 00010206 RAX: 0000000020000047 RBX: 00007fffffffefc0 RCX: ffffc90005dd1000 RDX: ffffffffffffffff RSI: ffffffff81b4d7e3 RDI: 0000000000000282 RBP: ffff88803e98fc00 R08: ffff888055286380 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88803e98fe00 R13: ffff88803e98fd00 R14: 0000000020000040 R15: 0000000020000040 __do_sys_perf_event_open+0x14b/0x3030 kernel/events/core.c:10442 __se_sys_perf_event_open kernel/events/core.c:10420 [inline] __x64_sys_perf_event_open+0xbe/0x150 kernel/events/core.c:10420 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:00007f61406d4c78 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000457ec9 RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000000020000040 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 00007f61406d56d4 R13: 00000000004c43bf R14: 00000000004d7708 R15: 00000000ffffffff Allocated by task 25560: 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 25567: 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 ffff888096a35d68 which belongs to the cache vm_area_struct(17:syz0) of size 200 The buggy address is located 64 bytes inside of 200-byte region [ffff888096a35d68, ffff888096a35e30) The buggy address belongs to the page: page:ffffea00025a8d40 count:1 mapcount:0 mapping:ffff888099cd43c0 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea000297b388 ffffea00029ff808 ffff888099cd43c0 raw: 0000000000000000 ffff888096a35000 000000010000000f ffff8880589b0040 page dumped because: kasan: bad access detected page->mem_cgroup:ffff8880589b0040 Memory state around the buggy address: ffff888096a35c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888096a35d00: fb fb fb fb fb fc fc fc fc fc fc fc fc fb fb fb >ffff888096a35d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888096a35e00: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fb fb ffff888096a35e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================