On 4/7/21 5:19 PM, Pingfan Liu wrote:
On RHEL9, crash hits a bug when executing "crash /proc/kcore" :
seek error: kernel virtual address: ffff6a0f3fff0000 type: "pmd page"
The kernel virtual address does not vary with va_actual bits, instead,
is determined by configuration value. But crash does not observe this
fact.
Since this disagreement only happens if 52-bits kernel on 48 bits platform,
it can be handled only if "memstart_addr < 0".
Signed-off-by: Pingfan Liu <[email protected]>
Cc: HAGIO KAZUHITO <[email protected]>
Cc: Lianbo Jiang <[email protected]>
Cc: Bhupesh Sharma <[email protected]>
Cc: Mark Salter <[email protected]>
Cc: Mark Langsdorf <[email protected]>
Cc: Jeremy Linton <[email protected]>
To: [email protected]
---
v1->v2: no change
arm64.c | 10 +++++++++-
defs.h | 1 +
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/arm64.c b/arm64.c
index db36d98..28d9373 100644
--- a/arm64.c
+++ b/arm64.c
@@ -220,7 +220,15 @@ arm64_init(int when)
arm64_calc_VA_BITS();
arm64_calc_KERNELPACMASK();
ms = machdep->machspec;
- if (ms->VA_BITS_ACTUAL) {
+ /* For 52-bits kernel running on 48 bits platform */
+ if (ms->memstart_addr < 0) {
Here is a mistake.
Based on "crash-utility/arm64: store phy_offset and memstart_addr
separately", it should be "ms->phys_offset_nominal"
For rest, any ideas?
Thanks,
Pingfan
+ ms->page_offset = ARM64_FLIP_PAGE_OFFSET;
+ /* useless on arm64 */
+ machdep->identity_map_base = ARM64_FLIP_PAGE_OFFSET;
+ machdep->kvbase = ARM64_FLIP_PAGE_OFFSET;
+ ms->userspace_top = ARM64_USERSPACE_TOP_ACTUAL;
+ /* For 52-bits on 52-bits platform, or 48-bits on 48 */
+ } else if (ms->VA_BITS_ACTUAL) {
ms->page_offset = ARM64_FLIP_PAGE_OFFSET_ACTUAL;
machdep->identity_map_base =
ARM64_FLIP_PAGE_OFFSET_ACTUAL;
machdep->kvbase = ARM64_FLIP_PAGE_OFFSET_ACTUAL;
diff --git a/defs.h b/defs.h
index 812f02f..27e15c9 100644
--- a/defs.h
+++ b/defs.h
@@ -3220,6 +3220,7 @@ typedef signed int s32;
#define ARM64_PAGE_OFFSET ((0xffffffffffffffffUL) \
<< (machdep->machspec->VA_BITS - 1))
/* kernels > v5.4 the kernel VA space is flipped */
+#define ARM64_FLIP_PAGE_OFFSET (-(1UL) <<
machdep->machspec->CONFIG_ARM64_VA_BITS)
#define ARM64_FLIP_PAGE_OFFSET_ACTUAL ((0xffffffffffffffffUL) \
- ((1UL) <<
machdep->machspec->VA_BITS_ACTUAL) + 1)
--
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