Hi Bhupesh, Baoquan,
As for x86_64, I'm going to merge the patch below for fixing the
--mem-usage issue with kernel 4.19, if there is no objection.
I think the same approach will also work on arm64 with regard to
page_offset for the time being..
Thanks,
Kazu
--
From: Kazuhito Hagio <k-hagio@xxxxxxxxxxxxx>
Date: Fri, 26 Oct 2018 14:43:22 -0400
Subject: [PATCH] x86_64: Fix calculation of page_offset for kernel 4.19
* Required for kernel 4.19
Kernel commit 6855dc41b24619c3d1de3dbd27dd0546b0e45272 ("x86: Add
entry trampolines to kcore") added program headers for PTI entry
trampoline pages to /proc/kcore.
This caused the failure of makedumpfile --mem-usage due to wrong
calculation of page_offset.
# makedumpfile --mem-usage /proc/kcore
[...]
set_kcore_vmcoreinfo: Can't get the offset of VMCOREINFO(/proc/kcore). Success
makedumpfile Failed.
Since program headers for linear maps are located after ones for
kernel text and so on in /proc/vmcore and /proc/kcore, with this
patch, we use the last valid one to set page_offset.
Also, this patch adds a few debug messages for better debugging.
Cc: Bhupesh Sharma <bhsharma@xxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Signed-off-by: Kazuhito Hagio <k-hagio@xxxxxxxxxxxxx>
---
arch/x86_64.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/arch/x86_64.c b/arch/x86_64.c
index 2b3c0bb..ed2a970 100644
--- a/arch/x86_64.c
+++ b/arch/x86_64.c
@@ -95,10 +95,17 @@ get_page_offset_x86_64(void)
ERRMSG("Can't read page_offset_base.\n");
return FALSE;
}
+ DEBUG_MSG("page_offset : %lx (from page_offset_base)\n",
+ info->page_offset);
return TRUE;
}
if (get_num_pt_loads()) {
+ /*
+ * Since program headers for linear maps are located after
+ * ones for kernel text and so on in /proc/vmcore and
+ * /proc/kcore, we use the last valid one to set page_offset.
+ */
for (i = 0;
get_pt_load(i, &phys_start, NULL, &virt_start, NULL);
i++) {
@@ -106,9 +113,13 @@ get_page_offset_x86_64(void)
&& virt_start < __START_KERNEL_map
&& phys_start != NOT_PADDR) {
info->page_offset = virt_start - phys_start;
- return TRUE;
}
}
+ if (info->page_offset) {
+ DEBUG_MSG("page_offset : %lx (from pt_load)\n",
+ info->page_offset);
+ return TRUE;
+ }
}
if (info->kernel_version < KERNEL_VERSION(2, 6, 27)) {
@@ -119,6 +130,7 @@ get_page_offset_x86_64(void)
info->page_offset = __PAGE_OFFSET_2_6_27;
}
+ DEBUG_MSG("page_offset : %lx (from constant)\n", info->page_offset);
return TRUE;
}
--
1.8.3.1
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