vdso: print fatal signals

Add the print-fatal-signals=1 boot option and the
/proc/sys/kernel/print-fatal-signals runtime switch.

This feature prints some minimal information about userspace segfaults to
the kernel console.  This is useful to find early bootup bugs where
userspace debugging is very hard.

Defaults to off.

[akpm@linux-foundation.org: Don't add new sysctl numbers]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ingo Molnar 2007-07-15 23:40:10 -07:00 committed by Linus Torvalds
parent 99fc06df72
commit 45807a1df9
3 changed files with 48 additions and 0 deletions

View file

@ -718,6 +718,37 @@ out_set:
#define LEGACY_QUEUE(sigptr, sig) \
(((sig) < SIGRTMIN) && sigismember(&(sigptr)->signal, (sig)))
int print_fatal_signals;
static void print_fatal_signal(struct pt_regs *regs, int signr)
{
printk("%s/%d: potentially unexpected fatal signal %d.\n",
current->comm, current->pid, signr);
#ifdef __i386__
printk("code at %08lx: ", regs->eip);
{
int i;
for (i = 0; i < 16; i++) {
unsigned char insn;
__get_user(insn, (unsigned char *)(regs->eip + i));
printk("%02x ", insn);
}
}
#endif
printk("\n");
show_regs(regs);
}
static int __init setup_print_fatal_signals(char *str)
{
get_option (&str, &print_fatal_signals);
return 1;
}
__setup("print-fatal-signals=", setup_print_fatal_signals);
static int
specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
@ -1855,6 +1886,8 @@ relock:
* Anything else is fatal, maybe with a core dump.
*/
current->flags |= PF_SIGNALED;
if ((signr != SIGKILL) && print_fatal_signals)
print_fatal_signal(regs, signr);
if (sig_kernel_coredump(signr)) {
/*
* If it was able to dump core, this kills all