================================================================== BUG: KASAN: slab-out-of-bounds in tick_sched_handle+0x16c/0x180 kernel/time/tick-sched.c:161 Read of size 8 at addr ffff8881830e5ce0 by task syz-executor2/15400 CPU: 1 PID: 15400 Comm: syz-executor2 Not tainted 4.20.0-rc6-next-20181214+ #171 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+0x244/0x39d lib/dump_stack.c:113 print_address_description.cold.4+0x9/0x1ff mm/kasan/report.c:187 kasan_report.cold.5+0x1b/0x39 mm/kasan/report.c:317 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 tick_sched_handle+0x16c/0x180 kernel/time/tick-sched.c:161 tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1271 __run_hrtimer kernel/time/hrtimer.c:1389 [inline] __hrtimer_run_queues+0x41c/0x10d0 kernel/time/hrtimer.c:1451 kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 6234 Comm: syz-executor5 Not tainted 4.20.0-rc6-next-20181214+ #171 hrtimer_interrupt+0x313/0x780 kernel/time/hrtimer.c:1509 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline] smp_apic_timer_interrupt+0x1a1/0x760 arch/x86/kernel/apic/apic.c:1060 RIP: 0010:find_stack lib/stackdepot.c:189 [inline] RIP: 0010:depot_save_stack+0x121/0x470 lib/stackdepot.c:238 Code: 0f 00 4e 8b 24 f5 40 0c 4f 8b 4d 85 e4 0f 84 d4 00 00 00 44 8d 47 ff 49 c1 e0 03 eb 0d 4d 8b 24 24 4d 85 e4 0f 84 bd 00 00 00 <41> 39 5c 24 08 75 ec 41 3b 7c 24 0c 75 e5 48 8b 01 49 39 44 24 18 RSP: 0018:ffff8881850ff6a8 EFLAGS: 00010286 RAX: 0000000064516192 RBX: 0000000010ec6775 RCX: ffff8881850ff708 RDX: 0000000045c5b632 RSI: 00000000006080c0 RDI: 0000000000000008 RBP: ffff8881850ff6e0 R08: 0000000000000038 R09: 00000000f8e03f20 R10: 00000000fe5ad609 R11: ffff8881dac2dbbb R12: c691744c9e2d4500 R13: ffff8881850ff6f0 R14: 00000000000c6775 R15: ffff8881d7dab52f FS: 0000000002371940(0000) GS:ffff8881dac00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000237a978 CR3: 00000001850c9000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 save_stack+0xa9/0xd0 mm/kasan/common.c:79 Allocated by task 6053: save_stack+0x43/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] kasan_kmalloc+0xcb/0xd0 mm/kasan/common.c:482 kasan_slab_alloc+0x12/0x20 mm/kasan/common.c:397 kmem_cache_alloc+0x130/0x730 mm/slab.c:3541 getname_flags+0xd0/0x590 fs/namei.c:140 getname+0x19/0x20 fs/namei.c:211 do_sys_open+0x383/0x780 fs/open.c:1057 __do_sys_open fs/open.c:1081 [inline] __se_sys_open fs/open.c:1076 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1076 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 6053: save_stack+0x43/0xd0 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+0x83/0x290 mm/slab.c:3747 putname+0xf2/0x130 fs/namei.c:261 set_track mm/kasan/common.c:85 [inline] kasan_kmalloc+0xcb/0xd0 mm/kasan/common.c:482 do_sys_open+0x54d/0x780 fs/open.c:1072 kmem_cache_alloc_trace+0x154/0x740 mm/slab.c:3607 __do_sys_open fs/open.c:1081 [inline] __se_sys_open fs/open.c:1076 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1076 kmalloc include/linux/slab.h:545 [inline] kzalloc include/linux/slab.h:740 [inline] ext4_htree_create_dir_info fs/ext4/dir.c:414 [inline] ext4_dx_readdir fs/ext4/dir.c:533 [inline] ext4_readdir+0x26d0/0x3b00 fs/ext4/dir.c:121 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8881830e4940 which belongs to the cache names_cache of size 4096 The buggy address is located 928 bytes to the right of 4096-byte region [ffff8881830e4940, ffff8881830e5940) The buggy address belongs to the page: page:ffffea00060c3900 count:1 mapcount:0 mapping:ffff8881da986e00 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000010200(slab|head) raw: 02fffc0000010200 ffffea00060c3888 ffffea00060c3a08 ffff8881da986e00 raw: 0000000000000000 ffff8881830e4940 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881830e5b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881830e5c00: fc fc fc fc fc 00 00 00 00 00 00 00 00 00 00 00 >ffff8881830e5c80: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc iterate_dir+0x48c/0x5f0 fs/readdir.c:51 ^ __do_sys_getdents fs/readdir.c:231 [inline] __se_sys_getdents fs/readdir.c:212 [inline] __x64_sys_getdents+0x29f/0x510 fs/readdir.c:212 ffff8881830e5d00: fc fc fc fc fc 00 00 00 00 00 00 00 00 00 00 00 ffff8881830e5d80: 00 00 00 f1 f1 f1 f1 00 f2 f2 f2 f2 f2 f2 f2 00 ================================================================== do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290