[POWERPC] Implement logging of unhandled signals
Implement show_unhandled_signals sysctl + support to print when a process is killed due to unhandled signals just as i386 and x86_64 does. Default to having it off, unlike x86 that defaults on. Signed-off-by: Olof Johansson <olof@lixom.net> Signed-off-by: Paul Mackerras <paulus@samba.org>
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@ -16,6 +16,12 @@
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#include "signal.h"
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/* Log an error when sending an unhandled signal to a process. Controlled
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* through debug.exception-trace sysctl.
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*/
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int show_unhandled_signals = 0;
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/*
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* Allocate space for the signal frame
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*/
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@ -705,11 +705,13 @@ int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,
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{
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struct rt_sigframe __user *rt_sf;
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struct mcontext __user *frame;
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void __user *addr;
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unsigned long newsp = 0;
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/* Set up Signal Frame */
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/* Put a Real Time Context onto stack */
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rt_sf = get_sigframe(ka, regs, sizeof(*rt_sf));
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addr = rt_sf;
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if (unlikely(rt_sf == NULL))
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goto badframe;
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@ -728,6 +730,7 @@ int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,
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/* Save user registers on the stack */
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frame = &rt_sf->uc.uc_mcontext;
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addr = frame;
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if (vdso32_rt_sigtramp && current->mm->context.vdso_base) {
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if (save_user_regs(regs, frame, 0))
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goto badframe;
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@ -742,6 +745,7 @@ int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,
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/* create a stack frame for the caller of the handler */
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newsp = ((unsigned long)rt_sf) - (__SIGNAL_FRAMESIZE + 16);
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addr = (void __user *)regs->gpr[1];
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if (put_user(regs->gpr[1], (u32 __user *)newsp))
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goto badframe;
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@ -762,6 +766,12 @@ badframe:
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printk("badframe in handle_rt_signal, regs=%p frame=%p newsp=%lx\n",
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regs, frame, newsp);
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#endif
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if (show_unhandled_signals && printk_ratelimit())
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printk(KERN_INFO "%s[%d]: bad frame in handle_rt_signal32: "
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"%p nip %08lx lr %08lx\n",
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current->comm, current->pid,
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addr, regs->nip, regs->link);
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force_sigsegv(sig, current);
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return 0;
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}
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@ -886,6 +896,12 @@ long sys_rt_sigreturn(int r3, int r4, int r5, int r6, int r7, int r8,
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return 0;
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bad:
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if (show_unhandled_signals && printk_ratelimit())
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printk(KERN_INFO "%s[%d]: bad frame in sys_rt_sigreturn: "
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"%p nip %08lx lr %08lx\n",
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current->comm, current->pid,
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rt_sf, regs->nip, regs->link);
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force_sig(SIGSEGV, current);
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return 0;
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}
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@ -967,6 +983,13 @@ int sys_debug_setcontext(struct ucontext __user *ctx,
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* We kill the task with a SIGSEGV in this situation.
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*/
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if (do_setcontext(ctx, regs, 1)) {
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if (show_unhandled_signals && printk_ratelimit())
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printk(KERN_INFO "%s[%d]: bad frame in "
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"sys_debug_setcontext: %p nip %08lx "
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"lr %08lx\n",
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current->comm, current->pid,
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ctx, regs->nip, regs->link);
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force_sig(SIGSEGV, current);
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goto out;
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}
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@ -1048,6 +1071,12 @@ badframe:
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printk("badframe in handle_signal, regs=%p frame=%p newsp=%lx\n",
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regs, frame, newsp);
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#endif
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if (show_unhandled_signals && printk_ratelimit())
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printk(KERN_INFO "%s[%d]: bad frame in handle_signal32: "
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"%p nip %08lx lr %08lx\n",
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current->comm, current->pid,
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frame, regs->nip, regs->link);
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force_sigsegv(sig, current);
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return 0;
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}
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@ -1061,12 +1090,14 @@ long sys_sigreturn(int r3, int r4, int r5, int r6, int r7, int r8,
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struct sigcontext __user *sc;
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struct sigcontext sigctx;
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struct mcontext __user *sr;
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void __user *addr;
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sigset_t set;
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/* Always make any pending restarted system calls return -EINTR */
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current_thread_info()->restart_block.fn = do_no_restart_syscall;
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sc = (struct sigcontext __user *)(regs->gpr[1] + __SIGNAL_FRAMESIZE);
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addr = sc;
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if (copy_from_user(&sigctx, sc, sizeof(sigctx)))
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goto badframe;
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@ -1083,6 +1114,7 @@ long sys_sigreturn(int r3, int r4, int r5, int r6, int r7, int r8,
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restore_sigmask(&set);
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sr = (struct mcontext __user *)from_user_ptr(sigctx.regs);
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addr = sr;
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if (!access_ok(VERIFY_READ, sr, sizeof(*sr))
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|| restore_user_regs(regs, sr, 1))
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goto badframe;
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@ -1091,6 +1123,12 @@ long sys_sigreturn(int r3, int r4, int r5, int r6, int r7, int r8,
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return 0;
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badframe:
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if (show_unhandled_signals && printk_ratelimit())
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printk(KERN_INFO "%s[%d]: bad frame in sys_sigreturn: "
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"%p nip %08lx lr %08lx\n",
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current->comm, current->pid,
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addr, regs->nip, regs->link);
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force_sig(SIGSEGV, current);
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return 0;
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}
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@ -64,6 +64,11 @@ struct rt_sigframe {
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char abigap[288];
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} __attribute__ ((aligned (16)));
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static const char fmt32[] = KERN_INFO \
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"%s[%d]: bad frame in %s: %08lx nip %08lx lr %08lx\n";
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static const char fmt64[] = KERN_INFO \
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"%s[%d]: bad frame in %s: %016lx nip %016lx lr %016lx\n";
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/*
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* Set up the sigcontext for the signal frame.
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*/
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@ -315,6 +320,11 @@ badframe:
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printk("badframe in sys_rt_sigreturn, regs=%p uc=%p &uc->uc_mcontext=%p\n",
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regs, uc, &uc->uc_mcontext);
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#endif
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if (show_unhandled_signals && printk_ratelimit())
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printk(regs->msr & MSR_SF ? fmt64 : fmt32,
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current->comm, current->pid, "rt_sigreturn",
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(long)uc, regs->nip, regs->link);
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force_sig(SIGSEGV, current);
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return 0;
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}
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@ -398,6 +408,11 @@ badframe:
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printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n",
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regs, frame, newsp);
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#endif
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if (show_unhandled_signals && printk_ratelimit())
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printk(regs->msr & MSR_SF ? fmt64 : fmt32,
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current->comm, current->pid, "setup_rt_frame",
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(long)frame, regs->nip, regs->link);
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force_sigsegv(signr, current);
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return 0;
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}
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@ -172,11 +172,21 @@ int die(const char *str, struct pt_regs *regs, long err)
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void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
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{
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siginfo_t info;
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const char fmt32[] = KERN_INFO "%s[%d]: unhandled signal %d " \
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"at %08lx nip %08lx lr %08lx code %x\n";
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const char fmt64[] = KERN_INFO "%s[%d]: unhandled signal %d " \
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"at %016lx nip %016lx lr %016lx code %x\n";
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if (!user_mode(regs)) {
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if (die("Exception in kernel mode", regs, signr))
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return;
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}
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} else if (show_unhandled_signals &&
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unhandled_signal(current, signr) &&
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printk_ratelimit()) {
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printk(regs->msr & MSR_SF ? fmt64 : fmt32,
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current->comm, current->pid, signr,
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addr, regs->nip, regs->link, code);
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}
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memset(&info, 0, sizeof(info));
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info.si_signo = signr;
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@ -1221,7 +1221,7 @@ static ctl_table fs_table[] = {
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};
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static ctl_table debug_table[] = {
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#ifdef CONFIG_X86
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#if defined(CONFIG_X86) || defined(CONFIG_PPC)
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{
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.ctl_name = CTL_UNNUMBERED,
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.procname = "exception-trace",
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