• Wang Nan's avatar
    cgroup/kmemleak: add kmemleak_free() for cgroup deallocations. · 401507d6
    Wang Nan authored
    Commit ff7ee93f ("cgroup/kmemleak: Annotate alloc_page() for cgroup
    allocations") introduces kmemleak_alloc() for alloc_page_cgroup(), but
    corresponding kmemleak_free() is missing, which makes kmemleak be
    wrongly disabled after memory offlining.  Log is pasted at the end of
    this commit message.
    
    This patch add kmemleak_free() into free_page_cgroup().  During page
    offlining, this patch removes corresponding entries in kmemleak rbtree.
    After that, the freed memory can be allocated again by other subsystems
    without killing kmemleak.
    
      bash # for x in 1 2 3 4; do echo offline > /sys/devices/system/memory/memory$x/state ; sleep 1; done ; dmesg | grep leak
    
      Offlined Pages 32768
      kmemleak: Cannot insert 0xffff880016969000 into the object search tree (overlaps existing)
      CPU: 0 PID: 412 Comm: sleep Not tainted 3.17.0-rc5+ #86
      Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
      Call Trace:
        dump_stack+0x46/0x58
        create_object+0x266/0x2c0
        kmemleak_alloc+0x26/0x50
        kmem_cache_alloc+0xd3/0x160
        __sigqueue_alloc+0x49/0xd0
        __send_signal+0xcb/0x410
        send_signal+0x45/0x90
        __group_send_sig_info+0x13/0x20
        do_notify_parent+0x1bb/0x260
        do_exit+0x767/0xa40
        do_group_exit+0x44/0xa0
        SyS_exit_group+0x17/0x20
        system_call_fastpath+0x16/0x1b
    
      kmemleak: Kernel memory leak detector disabled
      kmemleak: Object 0xffff880016900000 (size 524288):
      kmemleak:   comm "swapper/0", pid 0, jiffies 4294667296
      kmemleak:   min_count = 0
      kmemleak:   count = 0
      kmemleak:   flags = 0x1
      kmemleak:   checksum = 0
      kmemleak:   backtrace:
            log_early+0x63/0x77
            kmemleak_alloc+0x4b/0x50
            init_section_page_cgroup+0x7f/0xf5
            page_cgroup_init+0xc5/0xd0
            start_kernel+0x333/0x408
            x86_64_start_reservations+0x2a/0x2c
            x86_64_start_kernel+0xf5/0xfc
    
    Fixes: ff7ee93f (cgroup/kmemleak: Annotate alloc_page() for cgroup allocations)
    Signed-off-by: default avatarWang Nan <wangnan0@huawei.com>
    Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
    Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: <stable@vger.kernel.org>	[3.2+]
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    401507d6
page_cgroup.c 12 KB