Messages in this thread | | | Date | Mon, 25 May 2009 18:21:55 +0200 | From | Jiri Slaby <> | Subject | Re: [PATCH 1/1] signal: make group kill signal fatal |
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On 05/25/2009 02:07 AM, Oleg Nesterov wrote: > On 05/24, Jiri Slaby wrote: >> >> __fatal_signal_pending() returns now true only for a non-group sent >> sigkill, i. e. for example tgkill, send_sig... > > No. Please look at complete_signal(). If we queue a fatal signal, > we always add SIGKILL to any thread.
Ah, thanks. But it looks like it doesn't work well in some cases. Consider this kernel code:
#include <linux/fs.h> #include <linux/miscdevice.h> #include <linux/module.h> #include <linux/poll.h> #include <linux/sched.h>
static int release(struct inode *ino, struct file *file) { unsigned int a; printk(KERN_DEBUG "fst\n"); for (a = 0; a < 10; a++) { printk(KERN_DEBUG "%s: SP=%u FSP=%u pend=%.16lx shpend=%.16lx\n", __func__, signal_pending(current), fatal_signal_pending(current), current->pending.signal.sig[0],
current->signal->shared_pending.signal.sig[0]); if (fatal_signal_pending(current)) break; msleep(1000); } printk(KERN_DEBUG "done\n"); return 0; }
static DECLARE_WAIT_QUEUE_HEAD(wq);
static unsigned int poll(struct file *file, struct poll_table_struct *p) { poll_wait(file, &wq, p);
return 0; }
static const struct file_operations fops = { .owner = THIS_MODULE, .release = release, .poll = poll, };
static struct miscdevice m = { .minor = MISC_DYNAMIC_MINOR, .name = "m", .fops = &fops, };
static int init1(void) { return misc_register(&m); }
static void exit1(void) { misc_deregister(&m); }
module_init(init1); module_exit(exit1);
MODULE_LICENSE("GPL");
---------------------------------------------- And this user code: #include <err.h> #include <fcntl.h> #include <poll.h> #include <stdio.h> #include <unistd.h> #include <sys/stat.h> #include <sys/types.h> #include <sys/wait.h>
int main(int argc, char **argv) { struct pollfd fds = { .events = POLLIN }; int fd;
fd = open("/dev/m", O_RDONLY); if (fd < 0) err(1, "open"); fds.fd = fd; if (poll(&fds, 1, -1) < 0) err(2, "poll"); close(fd); return 0; }
---------------------------------------------- It outputs: fst release: SP=1 FSP=0 pend=0000000000000000 shpend=0000000000000100 release: SP=1 FSP=0 pend=0000000000000000 shpend=0000000000000100 release: SP=1 FSP=0 pend=0000000000000000 shpend=0000000000000100 release: SP=1 FSP=0 pend=0000000000000000 shpend=0000000000000100 release: SP=1 FSP=0 pend=0000000000000000 shpend=0000000000000100 release: SP=1 FSP=0 pend=0000000000000000 shpend=0000000000000100 release: SP=1 FSP=0 pend=0000000000000000 shpend=0000000000000100 release: SP=1 FSP=0 pend=0000000000000000 shpend=0000000000000100 release: SP=1 FSP=0 pend=0000000000000000 shpend=0000000000000100 release: SP=1 FSP=0 pend=0000000000000000 shpend=0000000000000100 done
I.e. it won't get propagated to current->pending. Don't you have idea why? If the poll isn't there, it works well.
glibc 2.9, x86_64
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