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powerpc/traps: Avoid rate limit messages from show unhandled signals 

In the recent commit to add an explicit ratelimit state when showing
unhandled signals, commit 35a52a10c3 ("powerpc/traps: Use an
explicit ratelimit state for show_signal_msg()"), I put the check of
show_unhandled_signals and the ratelimit state before the call to
unhandled_signal() so as to avoid unnecessarily calling the latter
when show_unhandled_signals is false.

However that causes us to check the ratelimit state on every call, so
if we take a lot of *handled* signals that has the effect of making
the ratelimit code print warnings that callbacks have been suppressed
when they haven't.

So rearrange the code so that we check show_unhandled_signals first,
then call unhandled_signal() and finally check the ratelimit state.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
This commit is contained in:
Michael Ellerman 2018-08-16 15:27:47 +10:00
parent 993ff6d9df
commit 997dd26cb3
1 changed files with 7 additions and 8 deletions
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15
arch/powerpc/kernel/traps.c
View File

@ -315,22 +315,21 @@ 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)
{
if (!show_unhandled_signals_ratelimited())
static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
if (!show_unhandled_signals)
return;
if (!unhandled_signal(current, signr))
return;
if (!__ratelimit(&rs))
return;
pr_info("%s[%d]: %s (%d) at %lx nip %lx lr %lx code %x",
current->comm, current->pid, signame(signr), signr,
addr, regs->nip, regs->link, code);