From: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>
Fix for aarch64 with Linux v5.0 and later kernels that
contains commit 91fc957c9b1d ("arm64/bpf: don't allocate
BPF JIT programs in module memory") and the memory dump
is captured by virsh dump.
Without the patch, crash cannot find kimage_voffset so it
fails to run, like as:
# crash vmlinux Guest.dump
...
WARNING: kimage_voffset cannot be determined from the dumpfile.
Try using the command line option: --machdep kimage_voffset=<addr>
...
crash: read error: kernel virtual address: ffff0000112db978 type: "possible"
WARNING: cannot read cpu_possible_map
...
crash: vmlinux and Guest.dump do not match!
...
#
This issue happens on the memory dump which is captured by virsh dump
because kimage_voffset isn't stored if it's captured by virsh dump.
Signed-off-by: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>
---
arm64.c | 2 ++
defs.h | 3 +++
2 files changed, 5 insertions(+)
diff --git a/arm64.c b/arm64.c
index 7662d71..0831231 100644
--- a/arm64.c
+++ b/arm64.c
@@ -242,6 +242,8 @@ arm64_init(int when)
ms->modules_vaddr = ARM64_VA_START;
if (kernel_symbol_exists("kasan_init"))
ms->modules_vaddr += ARM64_KASAN_SHADOW_SIZE;
+ if (kernel_symbol_exists("bpf_jit_alloc_exec"))
+ ms->modules_vaddr += BPF_JIT_REGION_SIZE;
ms->modules_end = ms->modules_vaddr + ARM64_MODULES_VSIZE -1;
}
diff --git a/defs.h b/defs.h
index efa40b9..867da74 100644
--- a/defs.h
+++ b/defs.h
@@ -3164,6 +3164,9 @@ typedef signed int s32;
#define ARM64_MODULES_VSIZE MEGABYTES(128)
#define ARM64_KASAN_SHADOW_SIZE (1UL << (machdep->machspec->VA_BITS - 3))
+/* only used for v5.0 or later */
+#define BPF_JIT_REGION_SIZE MEGABYTES(128)
+
/*
* The following 3 definitions are the original values, but are obsolete
* for 3.17 and later kernels because they are now build-time calculations.
--
2.18.1
--
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