[PATCH 1/2] arm64: Improve error reporting on set_pte_at() checks

Hi Andrew,

On 16/12/15 03:01, Andrew Pinski wrote:

On Tue, Dec 9, 2015 at 17:26:56, Catalin Marinas
[off-list ref] wrote:

quoted

Currently the BUG_ON() checks do not give enough information about the PTEs being set. This patch changes BUG_ON to WARN_ONCE and dumps the values of the old and new PTEs.

This change broke building the mantis driver:

In file included from ./arch/arm64/include/asm/io.h:30:0,
                 from drivers/media/pci/mantis/mantis_i2c.c:21:
./arch/arm64/include/asm/pgtable.h: In function ?set_pte_at?:
./arch/arm64/include/asm/pgtable.h:281:3: error: implicit declaration
of function ?BUILD_BUG_ON_INVALID?
[-Werror=implicit-function-declaration]
   VM_WARN_ONCE(!pte_young(pte),
   ^

This is due to a missing include in include/linux/mmdebug.h, which
Julien Grall saw with CONFIG_XEN & !CONFIG_DEBUG_VM. There was some
discussion at [0], and a patch at [1].

The quick-and-dirty workaround is to toggle CONFIG_DEBUG_VM. It should
be fixed in the next rc.


Thanks,

James

[0] https://lkml.org/lkml/2015/12/14/489
[1] http://www.spinics.net/lists/linux-mm/msg98868.html