On 13/01/2017 12:15, Dmitry Vyukov wrote: > > I've commented out the WARNING for now, but I am seeing lots of > use-after-free's and rcu stalls involving mmu_spte_clear_track_bits: > > > BUG: KASAN: use-after-free in mmu_spte_clear_track_bits+0x186/0x190 > arch/x86/kvm/mmu.c:597 at addr ffff880068ae2008 > Read of size 8 by task syz-executor2/16715 > page:ffffea00016e6170 count:0 mapcount:0 mapping: (null) index:0x0 > flags: 0x500000000000000() > raw: 0500000000000000 0000000000000000 0000000000000000 00000000ffffffff > raw: ffffea00017ec5a0 ffffea0001783d48 ffff88006aec5d98 > page dumped because: kasan: bad access detected > CPU: 2 PID: 16715 Comm: syz-executor2 Not tainted 4.10.0-rc3+ #163 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:15 [inline] > dump_stack+0x292/0x3a2 lib/dump_stack.c:51 > kasan_report_error mm/kasan/report.c:213 [inline] > kasan_report+0x42d/0x460 mm/kasan/report.c:307 > __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:333 > mmu_spte_clear_track_bits+0x186/0x190 arch/x86/kvm/mmu.c:597 > drop_spte+0x24/0x280 arch/x86/kvm/mmu.c:1182 > kvm_zap_rmapp+0x119/0x260 arch/x86/kvm/mmu.c:1401 > kvm_unmap_rmapp+0x1d/0x30 arch/x86/kvm/mmu.c:1412 > kvm_handle_hva_range+0x54a/0x7d0 arch/x86/kvm/mmu.c:1565 > kvm_unmap_hva_range+0x2e/0x40 arch/x86/kvm/mmu.c:1591 > kvm_mmu_notifier_invalidate_range_start+0xae/0x140 > arch/x86/kvm/../../../virt/kvm/kvm_main.c:360 > __mmu_notifier_invalidate_range_start+0x1f8/0x300 mm/mmu_notifier.c:199 > mmu_notifier_invalidate_range_start include/linux/mmu_notifier.h:282 [inline] > unmap_vmas+0x14b/0x1b0 mm/memory.c:1368 > unmap_region+0x2f8/0x560 mm/mmap.c:2460 > do_munmap+0x7b8/0xfa0 mm/mmap.c:2657 > mmap_region+0x68f/0x18e0 mm/mmap.c:1612 > do_mmap+0x6a2/0xd40 mm/mmap.c:1450 > do_mmap_pgoff include/linux/mm.h:2031 [inline] > vm_mmap_pgoff+0x1a9/0x200 mm/util.c:305 > SYSC_mmap_pgoff mm/mmap.c:1500 [inline] > SyS_mmap_pgoff+0x22c/0x5d0 mm/mmap.c:1458 > SYSC_mmap arch/x86/kernel/sys_x86_64.c:95 [inline] > SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:86 > entry_SYSCALL_64_fastpath+0x1f/0xc2 > RIP: 0033:0x445329 > RSP: 002b:00007fb33933cb58 EFLAGS: 00000282 ORIG_RAX: 0000000000000009 > RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 0000000000445329 > RDX: 0000000000000003 RSI: 0000000000af1000 RDI: 0000000020000000 > RBP: 00000000006dfe90 R08: ffffffffffffffff R09: 0000000000000000 > R10: 0000000000000032 R11: 0000000000000282 R12: 0000000000700000 > R13: 0000000000000006 R14: ffffffffffffffff R15: 0000000020001000 > Memory state around the buggy address: > ffff880068ae1f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffff880068ae1f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >> ffff880068ae2000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff > ^ > ffff880068ae2080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff > ffff880068ae2100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff > ================================================================== This could be related to the gfn_to_rmap issues. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
