The patch titled
Subject: kmemleak: powerpc: skip scanning holes in the .bss section
has been added to the -mm tree. Its filename is
kmemleak-powerpc-skip-scanning-holes-in-the-bss-section.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kmemleak-powerpc-skip-scanning-holes-in-the-bss-section.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kmemleak-powerpc-skip-scanning-holes-in-the-bss-section.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Catalin Marinas <catalin.marinas@xxxxxxx>
Subject: kmemleak: powerpc: skip scanning holes in the .bss section
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)
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Alexander Graf <agraf@xxxxxxx>
Cc: Avi Kivity <avi@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Radim Krcmar <rkrcmar@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kernel/kvm.c | 7 +++++++
mm/kmemleak.c | 16 +++++++++++-----
2 files changed, 18 insertions(+), 5 deletions(-)
--- a/arch/powerpc/kernel/kvm.c~kmemleak-powerpc-skip-scanning-holes-in-the-bss-section
+++ a/arch/powerpc/kernel/kvm.c
@@ -22,6 +22,7 @@
#include <linux/kvm_host.h>
#include <linux/init.h>
#include <linux/export.h>
+#include <linux/kmemleak.h>
#include <linux/kvm_para.h>
#include <linux/slab.h>
#include <linux/of.h>
@@ -712,6 +713,12 @@ static void kvm_use_magic_page(void)
static __init void kvm_free_tmp(void)
{
+ /*
+ * Inform kmemleak about the hole in the .bss section since the
+ * corresponding pages will be unmapped with DEBUG_PAGEALLOC=y.
+ */
+ kmemleak_free_part(&kvm_tmp[kvm_tmp_index],
+ ARRAY_SIZE(kvm_tmp) - kvm_tmp_index);
free_reserved_area(&kvm_tmp[kvm_tmp_index],
&kvm_tmp[ARRAY_SIZE(kvm_tmp)], -1, NULL);
}
--- a/mm/kmemleak.c~kmemleak-powerpc-skip-scanning-holes-in-the-bss-section
+++ a/mm/kmemleak.c
@@ -1529,11 +1529,6 @@ static void kmemleak_scan(void)
}
rcu_read_unlock();
- /* data/bss scanning */
- scan_large_block(_sdata, _edata);
- scan_large_block(__bss_start, __bss_stop);
- scan_large_block(__start_ro_after_init, __end_ro_after_init);
-
#ifdef CONFIG_SMP
/* per-cpu sections scanning */
for_each_possible_cpu(i)
@@ -2071,6 +2066,17 @@ void __init kmemleak_init(void)
}
local_irq_restore(flags);
+ /* register the data/bss sections */
+ create_object((unsigned long)_sdata, _edata - _sdata,
+ KMEMLEAK_GREY, GFP_ATOMIC);
+ create_object((unsigned long)__bss_start, __bss_stop - __bss_start,
+ KMEMLEAK_GREY, GFP_ATOMIC);
+ /* only register .data..ro_after_init if not within .data */
+ if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata)
+ create_object((unsigned long)__start_ro_after_init,
+ __end_ro_after_init - __start_ro_after_init,
+ KMEMLEAK_GREY, GFP_ATOMIC);
+
/*
* This is the point where tracking allocations is safe. Automatic
* scanning is started during the late initcall. Add the early logged
_
Patches currently in -mm which might be from catalin.marinas@xxxxxxx are
kmemleak-powerpc-skip-scanning-holes-in-the-bss-section.patch
