Re: [PATCH 1/2] powerpc: Use seq_buf to avoid pr_cont() in __die()
flat view
From: Christophe Leroy <hidden>
Date: 2019-01-08 12:20:38
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
quoted hunk ↗ jump to hunk
Signed-off-by: Michael Ellerman <mpe@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;