Re: [PATCH 4.19 62/99] kmemleak: powerpc: skip scanning holes in the .bss section

From: Greg Kroah-Hartman
Date: Tue May 07 2019 - 08:52:11 EST


On Tue, May 07, 2019 at 04:58:09PM +0900, Nobuhiro Iwamatsu wrote:
> Hi,
>
> On Mon, May 06, 2019 at 04:32:35PM +0200, Greg Kroah-Hartman wrote:
> > [ Upstream commit 298a32b132087550d3fa80641ca58323c5dfd4d9 ]
> >
> > Commit 2d4f567103ff ("KVM: PPC: Introduce kvm_tmp framework") adds
> > kvm_tmp[] into the .bss section and then free the rest of unused spaces
> > back to the page allocator.
> >
> > kernel_init
> > kvm_guest_init
> > kvm_free_tmp
> > free_reserved_area
> > free_unref_page
> > free_unref_page_prepare
> >
> > With DEBUG_PAGEALLOC=y, it will unmap those pages from kernel. As the
> > result, kmemleak scan will trigger a panic when it scans the .bss
> > section with unmapped pages.
> >
> > This patch creates dedicated kmemleak objects for the .data, .bss and
> > potentially .data..ro_after_init sections to allow partial freeing via
> > the kmemleak_free_part() in the powerpc kvm_free_tmp() function.
> >
> > Link: http://lkml.kernel.org/r/20190321171917.62049-1-catalin.marinas@xxxxxxx
> > Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> > Reported-by: Qian Cai <cai@xxxxxx>
> > Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> (powerpc)
> > Tested-by: Qian Cai <cai@xxxxxx>
> > Cc: Paul Mackerras <paulus@xxxxxxxxx>
> > Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> > Cc: Avi Kivity <avi@xxxxxxxxxx>
> > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> > Cc: Radim Krcmar <rkrcmar@xxxxxxxxxx>
> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> > ---
> > arch/powerpc/kernel/kvm.c | 7 +++++++
> > mm/kmemleak.c | 16 +++++++++++-----
> > 2 files changed, 18 insertions(+), 5 deletions(-)
>
> This commit has other problems, so we also need the following commits:
>
> commit dce5b0bdeec61bdbee56121ceb1d014151d5cab1
> Author: Arnd Bergmann <arnd@xxxxxxxx>
> Date: Thu Apr 18 17:50:48 2019 -0700
>
> mm/kmemleak.c: fix unused-function warning
>
> The only references outside of the #ifdef have been removed, so now we
> get a warning in non-SMP configurations:
>
> mm/kmemleak.c:1404:13: error: unused function 'scan_large_block' [-Werror,-Wunused-function]
>
> Add a new #ifdef around it.
>
> Link: http://lkml.kernel.org/r/20190416123148.3502045-1-arnd@xxxxxxxx
> Fixes: 298a32b13208 ("kmemleak: powerpc: skip scanning holes in the .bss section")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
>
> Please apply this commit.

Now queued up, thanks!

greg k-h