Messages in this thread Patch in this message | | | Date | Tue, 27 Oct 2009 11:58:28 +0900 | From | Naohiro Ooiwa <> | Subject | Re: [PATCH] show message when exceeded rlimit of pending signals |
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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.
Signed-off-by: Naohiro Ooiwa <nooiwa@miraclelinux.com> Acked-by: Ingo Molnar <mingo@elte.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.
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); +} + /* * allocate a new signal queue record * - this may be called without locks if and only if t == current, otherwise an @@ -209,8 +217,12 @@ 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 +937,6 @@ 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
Ingo Molnar wrote: > * Naohiro Ooiwa <nooiwa@miraclelinux.com> wrote: > >> Hi Ingo, >> >> Now that you mention it, I think so, too. >> I update my patch. >> >> How is the following patch. >> Could you please review it. >> >> Thanks you. >> Naohiro Ooiwa >> >> >> >> Signed-off-by: Naohiro Ooiwa <nooiwa@miraclelinux.com> >> --- >> Documentation/kernel-parameters.txt | 9 ++++++++- >> kernel/signal.c | 16 +++++++++++++--- >> 2 files changed, 21 insertions(+), 4 deletions(-) >> >> diff --git a/Documentation/kernel-parameters.txt >> b/Documentation/kernel-parameters.txt >> index 9107b38..01c2723 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 >> + If you would like to know what the cause of a coredump >> + by signal number, if your working system may have >> + too many POSIX.1 timers, and when during the system >> + test,you may as well to enable this parameter. >> print-fatal-signals=1: print segfault info to >> - the kernel console. >> + the kernel console, and print caution that reached the >> + limit of pending signals to the kernel console. >> + When printed the caution messages, you can try >> + "ulimit -i unlimited". >> default: off. >> > > Here's a slightly improved version of the text: > > print-fatal-signals= > [KNL] debug: print fatal signals > > 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. > >> +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) > > With these things addressed it looks good to me: > > Acked-by: Ingo Molnar <mingo@elte.hu> > > Ingo >
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