[PATCH 2/7] powerpc/traps: Return early in show_signal_msg()

Murilo Opsfelder Araujo
2018-07-24T19:28:06Z

Modify logic of show_signal_msg() to return early, if possible. Replace
printk_ratelimited() by printk() and a default rate limit burst to limit
displaying unhandled signals messages.

Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
---
arch/powerpc/kernel/traps.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index cbd3dc365193..4faab4705774 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -301,6 +301,13 @@ void user_single_step_siginfo(struct task_struct *tsk,
info->si_addr = (void __user *)regs->nip;
}

+static bool show_unhandled_signals_ratelimited(void)
+{
+ static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+ return show_unhandled_signals && __ratelimit(&rs);
+}
+
static void show_signal_msg(int signr, struct pt_regs *regs, int code,
unsigned long addr)
{
@@ -309,11 +316,12 @@ static void show_signal_msg(int signr, struct pt_regs *regs, int code,
const char fmt64[] = KERN_INFO "%s[%d]: unhandled signal %d " \
"at %016lx nip %016lx lr %016lx code %x\n";

- if (show_unhandled_signals && unhandled_signal(current, signr)) {
- printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
- current->comm, current->pid, signr,
- addr, regs->nip, regs->link, code);
- }
+ if (!unhandled_signal(current, signr))
+ return;
+
+ printk(regs->msr & MSR_64BIT ? fmt64 : fmt32,
+ current->comm, current->pid, signr,
+ addr, regs->nip, regs->link, code);
}

void _exception_pkey(int signr, struct pt_regs *regs, int code,
@@ -326,7 +334,8 @@ void _exception_pkey(int signr, struct pt_regs *regs, int code,
return;
}

- show_signal_msg(signr, regs, code, addr);
+ if (show_unhandled_signals_ratelimited())
+ show_signal_msg(signr, regs, code, addr);

if (arch_irqs_disabled() && !arch_irq_disabled_regs(regs))
local_irq_enable();
--
2.17.1