** Description changed: ================================================================== BUG: KASan: use after free in task_numa_find_cpu+0x64c/0x890 at addr ffff880dd393ecd8 Read of size 8 by task qemu-system-x86/3998900 ============================================================================= BUG kmalloc-128 (Tainted: G B ): kasan: bad access detected ----------------------------------------------------------------------------- INFO: Allocated in task_numa_fault+0xc1b/0xed0 age=41980 cpu=18 pid=3998890 - __slab_alloc+0x4f8/0x560 - __kmalloc+0x1eb/0x280 - task_numa_fault+0xc1b/0xed0 - do_numa_page+0x192/0x200 - handle_mm_fault+0x808/0x1160 - __do_page_fault+0x218/0x750 - do_page_fault+0x1a/0x70 - page_fault+0x28/0x30 - SyS_poll+0x66/0x1a0 - system_call_fastpath+0x1a/0x1f + __slab_alloc+0x4f8/0x560 + __kmalloc+0x1eb/0x280 + task_numa_fault+0xc1b/0xed0 + do_numa_page+0x192/0x200 + handle_mm_fault+0x808/0x1160 + __do_page_fault+0x218/0x750 + do_page_fault+0x1a/0x70 + page_fault+0x28/0x30 + SyS_poll+0x66/0x1a0 + system_call_fastpath+0x1a/0x1f INFO: Freed in task_numa_free+0x1d2/0x200 age=62 cpu=18 pid=0 - __slab_free+0x2ab/0x3f0 - kfree+0x161/0x170 - task_numa_free+0x1d2/0x200 - finish_task_switch+0x1d2/0x210 - __schedule+0x5d4/0xc60 - schedule_preempt_disabled+0x40/0xc0 - cpu_startup_entry+0x2da/0x340 - start_secondary+0x28f/0x360 + __slab_free+0x2ab/0x3f0 + kfree+0x161/0x170 + task_numa_free+0x1d2/0x200 + finish_task_switch+0x1d2/0x210 + __schedule+0x5d4/0xc60 + schedule_preempt_disabled+0x40/0xc0 + cpu_startup_entry+0x2da/0x340 + start_secondary+0x28f/0x360 INFO: Slab 0xffffea00374e4f00 objects=37 used=17 fp=0xffff880dd393ecb0 flags=0x6ffff0000004080 INFO: Object 0xffff880dd393ecb0 @offset=11440 fp=0xffff880dd393f700 Bytes b4 ffff880dd393eca0: 0c 00 00 00 18 00 00 00 af 63 3a 04 01 00 00 00 .........c:..... Object ffff880dd393ecb0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff880dd393ecc0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff880dd393ecd0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff880dd393ece0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff880dd393ecf0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff880dd393ed00: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff880dd393ed10: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff880dd393ed20: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkk. CPU: 61 PID: 3998900 Comm: qemu-system-x86 Tainted: G B 3.13.0-65-generic #105 Hardware name: Supermicro X8QB6/X8QB6, BIOS 2.0c 06/11/2 - ffffea00374e4f00 ffff8816c572b420 ffffffff81a6ce35 ffff88045f00f500 - ffff8816c572b450 ffffffff81244aed ffff88045f00f500 ffffea00374e4f00 - ffff880dd393ecb0 0000000000000012 ffff8816c572b478 ffffffff8124ac36 + ffffea00374e4f00 ffff8816c572b420 ffffffff81a6ce35 ffff88045f00f500 + ffff8816c572b450 ffffffff81244aed ffff88045f00f500 ffffea00374e4f00 + ffff880dd393ecb0 0000000000000012 ffff8816c572b478 ffffffff8124ac36 Call Trace: - [<ffffffff81a6ce35>] dump_stack+0x45/0x56 - [<ffffffff81244aed>] print_trailer+0xfd/0x170 - [<ffffffff8124ac36>] object_err+0x36/0x40 - [<ffffffff8124cbf9>] kasan_report_error+0x1e9/0x3a0 - [<ffffffff8124d260>] kasan_report+0x40/0x50 - [<ffffffff810dda7c>] ? task_numa_find_cpu+0x64c/0x890 - [<ffffffff8124bee9>] __asan_load8+0x69/0xa0 - [<ffffffff814f5c38>] ? find_next_bit+0xd8/0x120 - [<ffffffff810dda7c>] task_numa_find_cpu+0x64c/0x890 - [<ffffffff810de16c>] task_numa_migrate+0x4ac/0x7b0 - [<ffffffff810de523>] numa_migrate_preferred+0xb3/0xc0 - [<ffffffff810e0b88>] task_numa_fault+0xb88/0xed0 - [<ffffffff8120ef02>] do_numa_page+0x192/0x200 - [<ffffffff81211038>] handle_mm_fault+0x808/0x1160 - [<ffffffff810d7dbd>] ? sched_clock_cpu+0x10d/0x160 - [<ffffffff81068c52>] ? native_load_tls+0x82/0xa0 - [<ffffffff81a7bd68>] __do_page_fault+0x218/0x750 - [<ffffffff810c2186>] ? hrtimer_try_to_cancel+0x76/0x160 - [<ffffffff81a6f5e7>] ? schedule_hrtimeout_range_clock.part.24+0xf7/0x1c0 - [<ffffffff81a7c2ba>] do_page_fault+0x1a/0x70 - [<ffffffff81a772e8>] page_fault+0x28/0x30 - [<ffffffff8128cbd4>] ? do_sys_poll+0x1c4/0x6d0 - [<ffffffff810e64f6>] ? enqueue_task_fair+0x4b6/0xaa0 - [<ffffffff810233c9>] ? sched_clock+0x9/0x10 - [<ffffffff810cf70a>] ? resched_task+0x7a/0xc0 - [<ffffffff810d0663>] ? check_preempt_curr+0xb3/0x130 - [<ffffffff8128b5c0>] ? poll_select_copy_remaining+0x170/0x170 - [<ffffffff810d3bc0>] ? wake_up_state+0x10/0x20 - [<ffffffff8112a28f>] ? drop_futex_key_refs.isra.14+0x1f/0x90 - [<ffffffff8112d40e>] ? futex_requeue+0x3de/0xba0 - [<ffffffff8112e49e>] ? do_futex+0xbe/0x8f0 - [<ffffffff81022c89>] ? read_tsc+0x9/0x20 - [<ffffffff8111bd9d>] ? ktime_get_ts+0x12d/0x170 - [<ffffffff8108f699>] ? timespec_add_safe+0x59/0xe0 - [<ffffffff8128d1f6>] SyS_poll+0x66/0x1a0 - [<ffffffff81a830dd>] system_call_fastpath+0x1a/0x1f + [<ffffffff81a6ce35>] dump_stack+0x45/0x56 + [<ffffffff81244aed>] print_trailer+0xfd/0x170 + [<ffffffff8124ac36>] object_err+0x36/0x40 + [<ffffffff8124cbf9>] kasan_report_error+0x1e9/0x3a0 + [<ffffffff8124d260>] kasan_report+0x40/0x50 + [<ffffffff810dda7c>] ? task_numa_find_cpu+0x64c/0x890 + [<ffffffff8124bee9>] __asan_load8+0x69/0xa0 + [<ffffffff814f5c38>] ? find_next_bit+0xd8/0x120 + [<ffffffff810dda7c>] task_numa_find_cpu+0x64c/0x890 + [<ffffffff810de16c>] task_numa_migrate+0x4ac/0x7b0 + [<ffffffff810de523>] numa_migrate_preferred+0xb3/0xc0 + [<ffffffff810e0b88>] task_numa_fault+0xb88/0xed0 + [<ffffffff8120ef02>] do_numa_page+0x192/0x200 + [<ffffffff81211038>] handle_mm_fault+0x808/0x1160 + [<ffffffff810d7dbd>] ? sched_clock_cpu+0x10d/0x160 + [<ffffffff81068c52>] ? native_load_tls+0x82/0xa0 + [<ffffffff81a7bd68>] __do_page_fault+0x218/0x750 + [<ffffffff810c2186>] ? hrtimer_try_to_cancel+0x76/0x160 + [<ffffffff81a6f5e7>] ? schedule_hrtimeout_range_clock.part.24+0xf7/0x1c0 + [<ffffffff81a7c2ba>] do_page_fault+0x1a/0x70 + [<ffffffff81a772e8>] page_fault+0x28/0x30 + [<ffffffff8128cbd4>] ? do_sys_poll+0x1c4/0x6d0 + [<ffffffff810e64f6>] ? enqueue_task_fair+0x4b6/0xaa0 + [<ffffffff810233c9>] ? sched_clock+0x9/0x10 + [<ffffffff810cf70a>] ? resched_task+0x7a/0xc0 + [<ffffffff810d0663>] ? check_preempt_curr+0xb3/0x130 + [<ffffffff8128b5c0>] ? poll_select_copy_remaining+0x170/0x170 + [<ffffffff810d3bc0>] ? wake_up_state+0x10/0x20 + [<ffffffff8112a28f>] ? drop_futex_key_refs.isra.14+0x1f/0x90 + [<ffffffff8112d40e>] ? futex_requeue+0x3de/0xba0 + [<ffffffff8112e49e>] ? do_futex+0xbe/0x8f0 + [<ffffffff81022c89>] ? read_tsc+0x9/0x20 + [<ffffffff8111bd9d>] ? ktime_get_ts+0x12d/0x170 + [<ffffffff8108f699>] ? timespec_add_safe+0x59/0xe0 + [<ffffffff8128d1f6>] SyS_poll+0x66/0x1a0 + [<ffffffff81a830dd>] system_call_fastpath+0x1a/0x1f Memory state around the buggy address: - ffff880dd393eb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc - ffff880dd393ec00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc + ffff880dd393eb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc + ffff880dd393ec00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff880dd393ec80: fc fc fc fc fc fc fb fb fb fb fb fb fb fb fb fb - ^ - ffff880dd393ed00: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc - ffff880dd393ed80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc + ^ + ffff880dd393ed00: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc + ffff880dd393ed80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== + + --------------------------8<-------------------------- + $ addr2line 0xffffffff810dda7c -e usr/lib/debug/boot/vmlinux-3.13.0-65-generic -f -i + task_numa_compare + /home/gavin/os/ubuntu-trusty-amd64/kernel/sched/fair.c:1084 + task_numa_find_cpu + /home/gavin/os/ubuntu-trusty-amd64/kernel/sched/fair.c:1170 + + + 1083 if (cur->numa_group == env->p->numa_group) { + 1084 imp = taskimp + task_weight(cur, env->src_nid) - + 1085 task_weight(cur, env->dst_nid); + + + In short, this is the use-after-free bug happens on the task_struct->numa_faults which is freed by the task_numa_free called by the finish_task_switch when the process is exiting. While the numa balance mechanism is triggering the do_numa_page fault and need to read the task_struct->numa_faults to determine if the current exiting process is needed to migrate to the other CPU for better memory access performance because of shorter distance to access memory on the other node.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1527643 Title: use after free of task_struct->numa_faults in task_numa_find_cpu To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1527643/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs