uml: dump registers on ptrace or wait failure

Provide a register dump if handle_trap fails.  Abstract out ptrace_dump_regs
since it now has two callers.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 25 insertions, 12 deletions

diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 29fd079c30b1..41bf8d1e14e0 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -44,6 +44,22 @@ int is_skas_winch(int pid, int fd, void *data)
         return(1);
 }
 
+static int ptrace_dump_regs(int pid)
+{
+        unsigned long regs[MAX_REG_NR];
+        int i;
+
+        if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
+                return -errno;
+        else {
+                printk("Stub registers -\n");
+                for(i = 0; i < ARRAY_SIZE(regs); i++)
+                        printk("\t%d - %lx\n", i, regs[i]);
+        }
+
+        return 0;
+}
+
 void wait_stub_done(int pid, int sig, char * fname)
 {
         int n, status, err;
@@ -67,18 +83,10 @@ void wait_stub_done(int pid, int sig, char * fname)
 
         if((n < 0) || !WIFSTOPPED(status) ||
            (WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status) != SIGTRAP)){
-                unsigned long regs[MAX_REG_NR];
-
-                if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
+                err = ptrace_dump_regs(pid);
+                if(err)
                         printk("Failed to get registers from stub, "
-                               "errno = %d\n", errno);
-                else {
-                        int i;
-
-                        printk("Stub registers -\n");
-                        for(i = 0; i < ARRAY_SIZE(regs); i++)
-                                printk("\t%d - %lx\n", i, regs[i]);
-                }
+                               "errno = %d\n", -err);
                 panic("%s : failed to wait for SIGUSR1/SIGTRAP, "
                       "pid = %d, n = %d, errno = %d, status = 0x%x\n",
                       fname, pid, n, errno, status);
@@ -142,9 +150,14 @@ static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu
 
                 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
                 if((err < 0) || !WIFSTOPPED(status) ||
-                   (WSTOPSIG(status) != SIGTRAP + 0x80))
+                   (WSTOPSIG(status) != SIGTRAP + 0x80)){
+                        err = ptrace_dump_regs(pid);
+                        if(err)
+                                printk("Failed to get registers from process, "
+                                       "errno = %d\n", -err);
                         panic("handle_trap - failed to wait at end of syscall, "
                               "errno = %d, status = %d\n", errno, status);
+                }
         }
 
         handle_syscall(regs);