On Mon, Jun 11, 2018 at 09:05:33AM -0700, Nathan Chancellor wrote:
From: Arnd Bergmann arnd@arndb.de
commit 590347e4000356f55eb10b03ced2686bd74dab40 upstream.
gcc-6.3 and earlier show a new warning after a seemingly unrelated change to the arm64 PAGE_KERNEL definition:
In file included from drivers/md/dm-bufio.c:14:0: drivers/md/dm-bufio.c: In function 'alloc_buffer': include/linux/sched/mm.h:182:56: warning: 'noio_flag' may be used uninitialized in this function [-Wmaybe-uninitialized] current->flags = (current->flags & ~PF_MEMALLOC_NOIO) | flags; ^
The same warning happened earlier on linux-3.18 for MIPS and I did a workaround for that, but now it's come back.
gcc-7 and newer are apparently smart enough to figure this out, and other architectures don't show it, so the best I could come up with is to rework the caller slightly in a way that makes it obvious enough to all arm64 compilers what is happening here.
Fixes: 41acec624087 ("arm64: kpti: Make use of nG dependent on arm64_kernel_unmapped_at_el0()") Link: https://patchwork.kernel.org/patch/9692829/ Cc: stable@vger.kernel.org Signed-off-by: Arnd Bergmann arnd@arndb.de [snitzer: moved declarations inside conditional, altered vmalloc return] Signed-off-by: Mike Snitzer snitzer@redhat.com [nc: Backport to 4.9, adjust context for lack of 19809c2da28a] Signed-off-by: Nathan Chancellor natechancellor@gmail.com
Hi Greg,
Resending this with a proper prefix and message, in case the other one fell through the cracks. I came across this warning when building with Google's stock GCC 4.9 toolchain on the OnePlus 6. Context was adjusted around lack of commit 19809c2da28a ("mm, vmalloc: use __GFP_HIGHMEM implicitly") in 4.9. Please apply when you get a chance.
Now queued up, thanks. The other one was still in my queue, give me a chance to catch up :)
greg k-h