• Will Deacon's avatar
    arm64: hugetlb: partial revert of 66b3923a · ff792584
    Will Deacon authored
    Commit 66b3923a ("arm64: hugetlb: add support for PTE contiguous bit")
    introduced support for huge pages using the contiguous bit in the PTE
    as opposed to block mappings, which may be slightly unwieldy (512M) in
    64k page configurations.
    
    Unfortunately, this support has resulted in some late regressions when
    running the libhugetlbfs test suite with 64k pages and CONFIG_DEBUG_VM
    as a result of a BUG:
    
     | readback (2M: 64):	------------[ cut here ]------------
     | kernel BUG at fs/hugetlbfs/inode.c:446!
     | Internal error: Oops - BUG: 0 [#1] SMP
     | Modules linked in:
     | CPU: 7 PID: 1448 Comm: readback Not tainted 4.5.0-rc7 #148
     | Hardware name: linux,dummy-virt (DT)
     | task: fffffe0040964b00 ti: fffffe00c2668000 task.ti: fffffe00c2668000
     | PC is at remove_inode_hugepages+0x44c/0x480
     | LR is at remove_inode_hugepages+0x264/0x480
    
    Rather than revert the entire patch, simply avoid advertising the
    contiguous huge page sizes for now while people are actively working on
    a fix. This patch can then be reverted once things have been sorted out.
    
    Cc: David Woods <dwoods@ezchip.com>
    Reported-by: default avatarSteve Capper <steve.capper@arm.com>
    Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
    ff792584
hugetlbpage.c 7.38 KB