bfa3841787
Resolves: RHEL-103425 Upstream: kdump-utils Conflict: None Signed-off-by: Baoquan He <bhe@redhat.com>
48 lines
1.8 KiB
Diff
48 lines
1.8 KiB
Diff
From ddb0bab1f7e1e43a802993aadad03f85a3c045a9 Mon Sep 17 00:00:00 2001
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From: Baoquan He <bhe@redhat.com>
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Date: Wed, 25 Jun 2025 23:30:24 +0800
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Subject: [PATCH] sysconfig: disable kfence in kdump kernel
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Content-type: text/plain
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In the current fedora and RHEL, below config items related to kfence
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feature are set by default:
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===
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CONFIG_HAVE_ARCH_KFENCE=y
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CONFIG_KFENCE=y
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CONFIG_KFENCE_SAMPLE_INTERVAL=100
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CONFIG_KFENCE_NUM_OBJECTS=255
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CONFIG_KFENCE_STRESS_TEST_FAULTS=0
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CONFIG_KFENCE_KUNIT_TEST=m
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===
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With them set, on x86_64, it will cost 2M extra memory used for kfence when
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page size if 4K; while on arm64 with 64K page size, it will cost 32M extra
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memory. This doesn't take memory cost of initializing and running kfence
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itself into account, here only saying the kfence objects and guarded
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pages. However, it doesn't make any sense to have kfence in a kdump
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kernel. Hence, disable kfence in kdump kernel to save crashkernel
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memory.
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Signed-off-by: Baoquan He <bhe@redhat.com>
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---
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gen-kdump-sysconfig.sh | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/gen-kdump-sysconfig.sh b/gen-kdump-sysconfig.sh
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index 8ed63ba6eb9d..ca2e7610bc59 100755
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--- a/gen-kdump-sysconfig.sh
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+++ b/gen-kdump-sysconfig.sh
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@@ -29,7 +29,7 @@ KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet log_buf_len swio
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# This variable lets us append arguments to the current kdump commandline
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# after processed by KDUMP_COMMANDLINE_REMOVE
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-KDUMP_COMMANDLINE_APPEND="irqpoll maxcpus=1 reset_devices novmcoredd cma=0 hugetlb_cma=0"
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+KDUMP_COMMANDLINE_APPEND="irqpoll maxcpus=1 reset_devices novmcoredd cma=0 hugetlb_cma=0 kfence.sample_interval=0"
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# This variable lets us append arguments to fadump (powerpc) capture kernel,
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# further to the parameters passed via the bootloader.
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--
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2.41.0
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