[Crash-utility] [PATCH 1/3] riscv64: Set VMEMMAP flag to fix spurious mem_map[] warnings
RISC-V kernels use CONFIG_SPARSEMEM_VMEMMAP, and the crash utility
correctly reads VMEMMAP_START/VMEMMAP_END from VMCOREINFO. However,
riscv64.c never sets the VMEMMAP flag on machdep->flags, unlike arm64
and x86_64 which always set it.
This causes fill_mem_map_cache() in memory.c to emit spurious warnings
when it fails to read page structs from vmemmap holes:
WARNING: mem_map[] from ffff8d8002470000 to ffff8d8002471000 not accessible
With SPARSEMEM_VMEMMAP, unmapped holes in the vmemmap region are
expected -- a mem_section that has no corresponding physical memory
simply has no page struct mapped. The VMEMMAP flag tells crash that
such read failures are normal, suppressing the inappropriate warnings.
Set VMEMMAP in the PRE_GDB stage when vmemmap_vaddr is valid, and
display the flag in riscv64_dump_machdep_table() for debugging.
Signed-off-by: Rui Qi <qirui.001(a)bytedance.com>
---
riscv64.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/riscv64.c b/riscv64.c
index f0783d570c7b..a43afbdcebd2 100644
--- a/riscv64.c
+++ b/riscv64.c
@@ -244,6 +244,8 @@ riscv64_dump_machdep_table(ulong arg)
fprintf(fp, "%sIRQ_STACKS", others++ ? "|" : "");
if (machdep->flags & OVERFLOW_STACKS)
fprintf(fp, "%sOVERFLOW_STACKS", others++ ? "|" : "");
+ if (machdep->flags & VMEMMAP)
+ fprintf(fp, "%sVMEMMAP", others++ ? "|" : "");
fprintf(fp, ")\n");
fprintf(fp, " kvbase: %lx\n", machdep->kvbase);
@@ -1749,6 +1751,9 @@ riscv64_init(int when)
machdep->show_interrupts = generic_show_interrupts;
machdep->get_irq_affinity = generic_get_irq_affinity;
machdep->init_kernel_pgd = NULL; /* pgd set by
symbol_value("swapper_pg_dir") */
+
+ if (machdep->machspec->vmemmap_vaddr)
+ machdep->flags |= VMEMMAP;
break;
case POST_GDB:
--
2.20.1