um: print info about fatal segfaults

Print a short info about fatal segfaults like other archs do.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index 637c6505dc00..8c7b8823d1f0 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -113,6 +113,27 @@ out_of_memory:
         return 0;
 }
 
+static void show_segv_info(struct uml_pt_regs *regs)
+{
+        struct task_struct *tsk = current;
+        struct faultinfo *fi = UPT_FAULTINFO(regs);
+
+        if (!unhandled_signal(tsk, SIGSEGV))
+                return;
+
+        if (!printk_ratelimit())
+                return;
+
+        printk("%s%s[%d]: segfault at %lx ip %p sp %p error %x",
+                task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
+                tsk->comm, task_pid_nr(tsk), FAULT_ADDRESS(*fi),
+                (void *)UPT_IP(regs), (void *)UPT_SP(regs),
+                fi->error_code);
+
+        print_vma_addr(KERN_CONT " in ", UPT_IP(regs));
+        printk(KERN_CONT "\n");
+}
+
 static void bad_segv(struct faultinfo fi, unsigned long ip)
 {
         struct siginfo si;
@@ -141,6 +162,7 @@ void segv_handler(int sig, struct uml_pt_regs *regs)
         struct faultinfo * fi = UPT_FAULTINFO(regs);
 
         if (UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)) {
+                show_segv_info(regs);
                 bad_segv(*fi, UPT_IP(regs));
                 return;
         }
@@ -202,6 +224,8 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
                       address, ip);
         }
 
+        show_segv_info(regs);
+
         if (err == -EACCES) {
                 si.si_signo = SIGBUS;
                 si.si_errno = 0;