Le 08/01/2019 à 13:04, Michael Ellerman a écrit :
Using pr_cont() risks having our output interleaved with other output
from other CPUs. Instead use a seq_buf to construct the line and then
print it as a whole.

Why not simply doing a single printk() or similar on the same model as X86 for instance ? (https://elixir.bootlin.com/linux/v5.0-rc1/source/arch/x86/kernel/dumpstack.c#L368)

Christophe


Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
---
  arch/powerpc/kernel/traps.c | 23 ++++++++++++++++-------
  1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 64936b60d521..431a86d3f772 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -38,6 +38,7 @@
  #include <linux/kdebug.h>
  #include <linux/ratelimit.h>
  #include <linux/context_tracking.h>
+#include <linux/seq_buf.h>
  #include <linux/smp.h>
  #include <linux/console.h>
  #include <linux/kmsg_dump.h>
@@ -255,26 +256,34 @@ NOKPROBE_SYMBOL(oops_end);
static int __die(const char *str, struct pt_regs *regs, long err)
  {
+       char buf[128]; /* enough for all flags and a long platform name */
+       struct seq_buf s;
+
+       seq_buf_init(&s, buf, sizeof(buf));
+
        printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
if (IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN))
-               printk("LE ");
+               seq_buf_puts(&s, "LE ");
        else
-               printk("BE ");
+               seq_buf_puts(&s, "BE ");
if (IS_ENABLED(CONFIG_PREEMPT))
-               pr_cont("PREEMPT ");
+               seq_buf_puts(&s, "PREEMPT ");
if (IS_ENABLED(CONFIG_SMP))
-               pr_cont("SMP NR_CPUS=%d ", NR_CPUS);
+               seq_buf_printf(&s, "SMP NR_CPUS=%d ", NR_CPUS);
if (debug_pagealloc_enabled())
-               pr_cont("DEBUG_PAGEALLOC ");
+               seq_buf_puts(&s, "DEBUG_PAGEALLOC ");
if (IS_ENABLED(CONFIG_NUMA))
-               pr_cont("NUMA ");
+               seq_buf_puts(&s, "NUMA ");
+
+       if (ppc_md.name)
+               seq_buf_puts(&s, ppc_md.name);
- pr_cont("%s\n", ppc_md.name ? ppc_md.name : "");
+       printk("%s\n", buf);
if (notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV) == NOTIFY_STOP)
                return 1;

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