• Tejun Heo's avatar
    percpu: pcpu_embed_first_chunk() should free unused parts after all allocs are complete · 42b64281
    Tejun Heo authored
    pcpu_embed_first_chunk() allocates memory for each node, copies percpu
    data and frees unused portions of it before proceeding to the next
    group.  This assumes that allocations for different nodes doesn't
    overlap; however, depending on memory topology, the bootmem allocator
    may end up allocating memory from a different node than the requested
    one which may overlap with the portion freed from one of the previous
    percpu areas.  This leads to percpu groups for different nodes
    overlapping which is a serious bug.
    
    This patch separates out copy & partial free from the allocation loop
    such that all allocations are complete before partial frees happen.
    
    This also fixes overlapping frees which could happen on allocation
    failure path - out_free_areas path frees whole groups but the groups
    could have portions freed at that point.
    Signed-off-by: default avatarTejun Heo <tj@kernel.org>
    Cc: stable@vger.kernel.org
    Reported-by: default avatar"Pavel V. Panteleev" <pp_84@mail.ru>
    Tested-by: default avatar"Pavel V. Panteleev" <pp_84@mail.ru>
    LKML-Reference: <E1SNhwY-0007ui-V7.pp_84-mail-ru@f220.mail.ru>
    42b64281
percpu.c 56.9 KB