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    Subject[GIT PULL] core/signal for v2.6.33
    Linus,

    Please pull the latest core-signal-for-linus git tree from:

    git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git core-signal-for-linus

    Thanks,

    Ingo

    ------------------>
    Naohiro Ooiwa (1):
    signal: Print warning message when dropping signals

    Sebastian Andrzej Siewior (1):
    signal: Fix alternate signal stack check


    Documentation/kernel-parameters.txt | 11 +++++++-
    include/linux/sched.h | 13 +++++++--
    kernel/signal.c | 46 +++++++++++++++++++++++++----------
    3 files changed, 52 insertions(+), 18 deletions(-)

    diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
    index 9107b38..3bbd92f 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/include/linux/sched.h b/include/linux/sched.h
    index 75e6e60..0f67914 100644
    --- a/include/linux/sched.h
    +++ b/include/linux/sched.h
    @@ -2086,11 +2086,18 @@ static inline int is_si_special(const struct siginfo *info)
    return info <= SEND_SIG_FORCED;
    }

    -/* True if we are on the alternate signal stack. */
    -
    +/*
    + * True if we are on the alternate signal stack.
    + */
    static inline int on_sig_stack(unsigned long sp)
    {
    - return (sp - current->sas_ss_sp < current->sas_ss_size);
    +#ifdef CONFIG_STACK_GROWSUP
    + return sp >= current->sas_ss_sp &&
    + sp - current->sas_ss_sp < current->sas_ss_size;
    +#else
    + return sp > current->sas_ss_sp &&
    + sp - current->sas_ss_sp <= current->sas_ss_size;
    +#endif
    }

    static inline int sas_ss_flags(unsigned long sp)
    diff --git a/kernel/signal.c b/kernel/signal.c
    index 6705320..fe08008 100644
    --- a/kernel/signal.c
    +++ b/kernel/signal.c
    @@ -22,6 +22,7 @@
    #include <linux/ptrace.h>
    #include <linux/signal.h>
    #include <linux/signalfd.h>
    +#include <linux/ratelimit.h>
    #include <linux/tracehook.h>
    #include <linux/capability.h>
    #include <linux/freezer.h>
    @@ -41,6 +42,8 @@

    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;
    @@ -159,7 +162,7 @@ int next_signal(struct sigpending *pending, sigset_t *mask)
    {
    unsigned long i, *s, *m, x;
    int sig = 0;
    -
    +
    s = pending->signal.sig;
    m = mask->sig;
    switch (_NSIG_WORDS) {
    @@ -184,17 +187,31 @@ int next_signal(struct sigpending *pending, sigset_t *mask)
    sig = ffz(~x) + 1;
    break;
    }
    -
    +
    return sig;
    }

    +static inline void print_dropped_signal(int sig)
    +{
    + static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
    +
    + if (!print_fatal_signals)
    + return;
    +
    + if (!__ratelimit(&ratelimit_state))
    + return;
    +
    + printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
    + current->comm, current->pid, sig);
    +}
    +
    /*
    * allocate a new signal queue record
    * - this may be called without locks if and only if t == current, otherwise an
    * appopriate lock must be held to stop the target task from exiting
    */
    -static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
    - int override_rlimit)
    +static struct sigqueue *
    +__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
    {
    struct sigqueue *q = NULL;
    struct user_struct *user;
    @@ -207,10 +224,15 @@ static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
    */
    user = get_uid(__task_cred(t)->user);
    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 {
    + print_dropped_signal(sig);
    + }
    +
    if (unlikely(q == NULL)) {
    atomic_dec(&user->sigpending);
    free_uid(user);
    @@ -869,7 +891,7 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
    else
    override_rlimit = 0;

    - q = __sigqueue_alloc(t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
    + q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
    override_rlimit);
    if (q) {
    list_add_tail(&q->list, &pending->list);
    @@ -925,8 +947,6 @@ 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",
    @@ -1293,19 +1313,19 @@ EXPORT_SYMBOL(kill_pid);
    * These functions support sending signals using preallocated sigqueue
    * structures. This is needed "because realtime applications cannot
    * afford to lose notifications of asynchronous events, like timer
    - * expirations or I/O completions". In the case of Posix Timers
    + * expirations or I/O completions". In the case of Posix Timers
    * we allocate the sigqueue structure from the timer_create. If this
    * allocation fails we are able to report the failure to the application
    * with an EAGAIN error.
    */
    -
    struct sigqueue *sigqueue_alloc(void)
    {
    - struct sigqueue *q;
    + struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);

    - if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0)))
    + if (q)
    q->flags |= SIGQUEUE_PREALLOC;
    - return(q);
    +
    + return q;
    }

    void sigqueue_free(struct sigqueue *q)

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