• Andrey Ryabinin's avatar
    mm: vmalloc: add flag preventing guard hole allocation · 71394fe5
    Andrey Ryabinin authored
    
    
    For instrumenting global variables KASan will shadow memory backing memory
    for modules.  So on module loading we will need to allocate memory for
    shadow and map it at address in shadow that corresponds to the address
    allocated in module_alloc().
    
    __vmalloc_node_range() could be used for this purpose, except it puts a
    guard hole after allocated area.  Guard hole in shadow memory should be a
    problem because at some future point we might need to have a shadow memory
    at address occupied by guard hole.  So we could fail to allocate shadow
    for module_alloc().
    
    Add a new vm_struct flag 'VM_NO_GUARD' indicating that vm area doesn't
    have a guard hole.
    Signed-off-by: default avatarAndrey Ryabinin <a.ryabinin@samsung.com>
    Cc: Dmitry Vyukov <dvyukov@google.com>
    Cc: Konstantin Serebryany <kcc@google.com>
    Cc: Dmitry Chernenkov <dmitryc@google.com>
    Signed-off-by: default avatarAndrey Konovalov <adech.fo@gmail.com>
    Cc: Yuri Gribov <tetra2005@gmail.com>
    Cc: Konstantin Khlebnikov <koct9i@gmail.com>
    Cc: Sasha Levin <sasha.levin@oracle.com>
    Cc: Christoph Lameter <cl@linux.com>
    Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
    Cc: Dave Hansen <dave.hansen@intel.com>
    Cc: Andi Kleen <andi@firstfloor.org>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Christoph Lameter <cl@linux.com>
    Cc: Pekka Enberg <penberg@kernel.org>
    Cc: David Rientjes <rientjes@google.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    71394fe5
vmalloc.c 68.1 KB