================================================================== BUG: KASAN: use-after-free in __lock_acquire+0x3c41/0x3cf0 kernel/locking/lockdep.c:3305 Read of size 8 at addr ffff8801c7b826d0 by task syzkaller982660/3781 CPU: 0 PID: 3781 Comm: syzkaller982660 Not tainted 4.15.0-rc6-mm1+ #50 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x137/0x198 lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report+0x23b/0x360 mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 __lock_acquire+0x3c41/0x3cf0 kernel/locking/lockdep.c:3305 lock_acquire+0x16b/0x420 kernel/locking/lockdep.c:3914 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:310 [inline] shmem_fault+0x503/0x710 mm/shmem.c:1981 __do_fault+0x8a/0x1d0 mm/memory.c:3224 do_shared_fault mm/memory.c:3689 [inline] do_fault mm/memory.c:3738 [inline] handle_pte_fault mm/memory.c:3965 [inline] __handle_mm_fault+0x1b1f/0x3210 mm/memory.c:4089 handle_mm_fault+0x305/0x840 mm/memory.c:4126 __do_page_fault+0x59e/0xca0 arch/x86/mm/fault.c:1429 do_page_fault+0x78/0x490 arch/x86/mm/fault.c:1504 page_fault+0x2c/0x60 arch/x86/entry/entry_64.S:1243 RIP: 0010:__clear_user+0x42/0x70 arch/x86/lib/usercopy_64.c:23 RSP: 0000:ffff8801d96a7bc8 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000008 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 000000002098ce40 RBP: ffff8801d96a7bd8 R08: 0000000000000000 R09: 0000000000000000 R10: ffff8801d96a7b18 R11: 0000000000000001 R12: 000000002098ce40 R13: ffff8801d7126700 R14: 000000002098cc40 R15: 00007ffffffff000 copy_xregs_to_user arch/x86/include/asm/fpu/internal.h:372 [inline] copy_fpregs_to_sigframe arch/x86/kernel/fpu/signal.c:126 [inline] copy_fpstate_to_sigframe+0x196/0x470 arch/x86/kernel/fpu/signal.c:177 get_sigframe.isra.11.constprop.12+0x52f/0x8b0 arch/x86/kernel/signal.c:284 __setup_rt_frame arch/x86/kernel/signal.c:465 [inline] setup_rt_frame arch/x86/kernel/signal.c:699 [inline] handle_signal arch/x86/kernel/signal.c:743 [inline] do_signal+0x3a4/0x1980 arch/x86/kernel/signal.c:811 exit_to_usermode_loop+0x1aa/0x210 arch/x86/entry/common.c:161 prepare_exit_to_usermode+0x22f/0x280 arch/x86/entry/common.c:195 retint_user+0x8/0x18 RIP: 0033: (null) RSP: 002b:000000002098d008 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00000000006f0024 RCX: 000000000044ad09 RDX: 0000000020651000 RSI: 000000002098d000 RDI: 00000000000001fe RBP: 00000000006f0020 R08: 000000002095c000 R09: 0000000000000000 R10: 0000000020c6f000 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000007ffe5f R14: 00007f4c6a1ac9c0 R15: 0000000000000003 Allocated by task 3721: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3541 shmem_alloc_inode+0x1b/0x40 mm/shmem.c:3843 alloc_inode+0x65/0x180 fs/inode.c:209 new_inode_pseudo+0x17/0xe0 fs/inode.c:890 new_inode+0x1c/0x40 fs/inode.c:919 shmem_get_inode+0x71/0x760 mm/shmem.c:2157 __shmem_file_setup.part.44+0x33f/0x420 mm/shmem.c:4218 __shmem_file_setup mm/shmem.c:4300 [inline] shmem_kernel_file_setup mm/shmem.c:4256 [inline] shmem_zero_setup+0xd9/0x3e0 mm/shmem.c:4300 mmap_region+0xdb8/0x1010 mm/mmap.c:1732 do_mmap+0x623/0xda0 mm/mmap.c:1494 do_mmap_pgoff include/linux/mm.h:2224 [inline] vm_mmap_pgoff+0x19c/0x1f0 mm/util.c:333 SYSC_mmap_pgoff mm/mmap.c:1544 [inline] SyS_mmap_pgoff+0x1fc/0x580 mm/mmap.c:1502 SYSC_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:91 entry_SYSCALL_64_fastpath+0x23/0x9a Freed by task 3721: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527 __cache_free mm/slab.c:3485 [inline] kmem_cache_free+0x86/0x2b0 mm/slab.c:3743 shmem_destroy_callback+0x5a/0xa0 mm/shmem.c:3854 __rcu_reclaim kernel/rcu/rcu.h:172 [inline] rcu_do_batch kernel/rcu/tree.c:2675 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2934 [inline] __rcu_process_callbacks kernel/rcu/tree.c:2901 [inline] rcu_process_callbacks+0x5cf/0x1200 kernel/rcu/tree.c:2918 __do_softirq+0x23f/0x99f kernel/softirq.c:285 The buggy address belongs to the object at ffff8801c7b82530 which belongs to the cache shmem_inode_cache of size 1200 The buggy address is located 416 bytes inside of 1200-byte region [ffff8801c7b82530, ffff8801c7b829e0) The buggy address belongs to the page: page:ffffea00071ee080 count:1 mapcount:0 mapping:ffff8801c7b82000 index:0xffff8801c7b82ffd flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801c7b82000 ffff8801c7b82ffd 0000000100000003 raw: ffffea00071edd20 ffffea0006fb86e0 ffff8801da2a44c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c7b82580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801c7b82600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801c7b82680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801c7b82700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801c7b82780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================