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Date: Tue, 27 Oct 2009 17:27:23 +0900
From: nooiwa <nooiwa@...aclelinux.com>
To: Hiroshi Shimamoto <h-shimamoto@...jp.nec.com>
CC: Ingo Molnar <mingo@...e.hu>, roland@...hat.com,
akpm@...ux-foundation.org, oleg@...hat.com,
LKML <linux-kernel@...r.kernel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: [PATCH] show message when exceeded rlimit of pending signals
Hi Hiroshi
> And nitpicks below.
Thank you so much.
Sorry, I will run scripts/checkpatch.pl in the next time.
> there are white spaces before tabs.
oops...
>> + printk(KERN_WARNING "%s/%d: reached the limit of pending signals.\n",
current->comm, current->pid);
>
> this line over 80 characters.
I deleted "KERN_WARNING", because there is not it in print_faital_signal().
Thanks you.
Naohiro Ooiwa
Signed-off-by: Naohiro Ooiwa <nooiwa@...aclelinux.com>
Acked-by: Ingo Molnar <mingo@...e.hu>
---
Documentation/kernel-parameters.txt | 11 +++++++++--
kernel/signal.c | 17 ++++++++++++++---
2 files changed, 23 insertions(+), 5 deletions(-)
diff --git a/Documentation/kernel-parameters.txt
b/Documentation/kernel-parameters.txt
index 9107b38..6b74dd4 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2032,8 +2032,15 @@ and is between 256 and 4096 characters. It is
defined in the file
print-fatal-signals=
[KNL] debug: print fatal signals
- print-fatal-signals=1: print segfault info to
- the kernel console.
+
+ If enabled, warn about various signal handling
+ related application anomalies: too many signals,
+ too many POSIX.1 timers, fatal signals causing a
+ coredump - etc.
+
+ If you hit the warning due to signal overflow,
+ you might want to try "ulimit -i unlimited".
+
default: off.
printk.time= Show timing data prefixed to each printk message line
diff --git a/kernel/signal.c b/kernel/signal.c
index 6705320..8588833 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -41,6 +41,8 @@
static struct kmem_cache *sigqueue_cachep;
+int print_fatal_signals __read_mostly;
+
static void __user *sig_handler(struct task_struct *t, int sig)
{
return t->sighand->action[sig - 1].sa.sa_handler;
@@ -188,6 +190,13 @@ int next_signal(struct sigpending *pending,
sigset_t *mask)
return sig;
}
+static void show_reach_rlimit_sigpending(void)
+{
+ if (printk_ratelimit())
+ printk("%s/%d: reached the limit of pending signals.\n",
+ current->comm, current->pid);
+}
+
/*
* allocate a new signal queue record
* - this may be called without locks if and only if t == current,
otherwise an
@@ -209,8 +218,12 @@ static struct sigqueue *__sigqueue_alloc(struct
task_struct *t, gfp_t flags,
atomic_inc(&user->sigpending);
if (override_rlimit ||
atomic_read(&user->sigpending) <=
- t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
+ t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) {
q = kmem_cache_alloc(sigqueue_cachep, flags);
+ } else {
+ if (print_fatal_signals)
+ show_reach_rlimit_sigpending();
+ }
if (unlikely(q == NULL)) {
atomic_dec(&user->sigpending);
free_uid(user);
@@ -925,8 +938,6 @@ static int send_signal(int sig, struct siginfo
*info, struct task_struct *t,
return __send_signal(sig, info, t, group, from_ancestor_ns);
}
-int print_fatal_signals;
-
static void print_fatal_signal(struct pt_regs *regs, int signr)
{
printk("%s/%d: potentially unexpected fatal signal %d.\n",
-- 1.5.4.1
Hiroshi Shimamoto wrote:
> Naohiro Ooiwa wrote:
>> Hi Ingo,
>>
>>> Here's a slightly improved version of the text:
>> Thank you for your review and collect my English.
>>
>>>> +int print_fatal_signals;
>>> i'd suggest __read_mostly.
>>> Plus please move variables to the top of the file. (i know this comes
>>> from the previous code but we can improve it while we are touching it)
>> Of course. You're right, if we found one like it,
>> I want to improve the code little by little too.
>>
>> How is the following patch.
>
> If you can provide a test case, it's helpful to confirm this improve.
> And nitpicks below.
>
>> Signed-off-by: Naohiro Ooiwa <nooiwa@...aclelinux.com>
>> Acked-by: Ingo Molnar <mingo@...e.hu>
>> ---
>> Documentation/kernel-parameters.txt | 13 ++++++++++---
>> kernel/signal.c | 16 +++++++++++++---
>> 2 files changed, 23 insertions(+), 6 deletions(-)
>>
>> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
>> index 9107b38..8492ad3 100644
>> --- a/Documentation/kernel-parameters.txt
>> +++ b/Documentation/kernel-parameters.txt
>> @@ -2032,9 +2032,16 @@ and is between 256 and 4096 characters. It is defined in the file
>>
>> print-fatal-signals=
>> [KNL] debug: print fatal signals
>> - print-fatal-signals=1: print segfault info to
>> - the kernel console.
>> - default: off.
>> +
>> + If enabled, warn about various signal handling
>> + related application anomalies: too many signals,
>> + too many POSIX.1 timers, fatal signals causing a
>> + coredump - etc.
>> +
>> + If you hit the warning due to signal overflow,
>> + you might want to try "ulimit -i unlimited".
>> +
>> + default: off.
>
> there are white spaces before tabs.
>
>> printk.time= Show timing data prefixed to each printk message line
>> Format: <bool> (1/Y/y=enable, 0/N/n=disable)
>> diff --git a/kernel/signal.c b/kernel/signal.c
>> index 6705320..c913eb7 100644
>> --- a/kernel/signal.c
>> +++ b/kernel/signal.c
>> @@ -41,6 +41,8 @@
>>
>> static struct kmem_cache *sigqueue_cachep;
>>
>> +int print_fatal_signals __read_mostly;
>> +
>> static void __user *sig_handler(struct task_struct *t, int sig)
>> {
>> return t->sighand->action[sig - 1].sa.sa_handler;
>> @@ -188,6 +190,12 @@ int next_signal(struct sigpending *pending, sigset_t *mask)
>> return sig;
>> }
>>
>> +static void show_reach_rlimit_sigpending(void)
>> +{
>> + if (printk_ratelimit())
>> + printk(KERN_WARNING "%s/%d: reached the limit of pending signals.\n", current->comm, current->pid);
>
> this line over 80 characters.
>
> thanks,
> Hiroshi
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