mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 08:19:28 +00:00
[PATCH] ppc32: Kill init on unhandled synchronous signals
This is a patch that I have had in my tree for ages. If init causes an exception that raises a signal, such as a SIGSEGV, SIGILL or SIGFPE, and it hasn't registered a handler for it, we don't deliver the signal, since init doesn't get any signals that it doesn't have a handler for. But that means that we just return to userland and generate the same exception again immediately. With this patch we print a message and kill init in this situation. This is very useful when you have a bug in the kernel that means that init doesn't get as far as executing its first instruction. :) Without this patch the system hangs when it gets to starting the userland init; with it you at least get a message giving you a clue about what has gone wrong. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
parent
1e63bc7342
commit
bb0bb3b659
3 changed files with 24 additions and 5 deletions
|
@ -118,6 +118,28 @@ void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
|
|||
info.si_code = code;
|
||||
info.si_addr = (void __user *) addr;
|
||||
force_sig_info(signr, &info, current);
|
||||
|
||||
/*
|
||||
* Init gets no signals that it doesn't have a handler for.
|
||||
* That's all very well, but if it has caused a synchronous
|
||||
* exception and we ignore the resulting signal, it will just
|
||||
* generate the same exception over and over again and we get
|
||||
* nowhere. Better to kill it and let the kernel panic.
|
||||
*/
|
||||
if (current->pid == 1) {
|
||||
__sighandler_t handler;
|
||||
|
||||
spin_lock_irq(¤t->sighand->siglock);
|
||||
handler = current->sighand->action[signr-1].sa.sa_handler;
|
||||
spin_unlock_irq(¤t->sighand->siglock);
|
||||
if (handler == SIG_DFL) {
|
||||
/* init has generated a synchronous exception
|
||||
and it doesn't have a handler for the signal */
|
||||
printk(KERN_CRIT "init has generated signal %d "
|
||||
"but has no handler for it\n", signr);
|
||||
do_exit(signr);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
|
@ -278,11 +278,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
|
|||
|
||||
/* User mode accesses cause a SIGSEGV */
|
||||
if (user_mode(regs)) {
|
||||
info.si_signo = SIGSEGV;
|
||||
info.si_errno = 0;
|
||||
info.si_code = code;
|
||||
info.si_addr = (void __user *) address;
|
||||
force_sig_info(SIGSEGV, &info, current);
|
||||
_exception(SIGSEGV, regs, code, address);
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
|
|
@ -88,6 +88,7 @@ extern void *cacheable_memcpy(void *, const void *, unsigned int);
|
|||
extern int do_page_fault(struct pt_regs *, unsigned long, unsigned long);
|
||||
extern void bad_page_fault(struct pt_regs *, unsigned long, int);
|
||||
extern void die(const char *, struct pt_regs *, long);
|
||||
extern void _exception(int, struct pt_regs *, int, unsigned long);
|
||||
#ifdef CONFIG_BOOKE_WDT
|
||||
extern u32 booke_wdt_enabled;
|
||||
extern u32 booke_wdt_period;
|
||||
|
|
Loading…
Reference in a new issue