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authorRichard Weinberger <richard@nod.at>2011-05-17 15:44:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-18 02:55:23 -0700
commitb2db21997f43907f54500edaf063253ca2a186f9 (patch)
treec98cabccfd71dea17520553fd534335a3d1c0a82
parentd6c438b6cd733834a3cec55af8577a8fc3548016 (diff)
downloadlinux-stericsson-b2db21997f43907f54500edaf063253ca2a186f9.tar.gz
um: fix abort
os_dump_core() uses abort() to terminate UML in case of an fatal error. glibc's abort() calls raise(SIGABRT) which makes use of tgkill(). tgkill() has no effect within UML's kernel threads because they are not pthreads. As fallback abort() executes an invalid instruction to terminate the process. Therefore UML gets killed by SIGSEGV and leaves a ugly log entry in the host's kernel ring buffer. To get rid of this we use our own abort routine. 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>
-rw-r--r--arch/um/os-Linux/util.c23
1 files changed, 22 insertions, 1 deletions
diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c
index 6ea77979531c..42827cafa6af 100644
--- a/arch/um/os-Linux/util.c
+++ b/arch/um/os-Linux/util.c
@@ -5,6 +5,7 @@
#include <stdio.h>
#include <stdlib.h>
+#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
@@ -75,6 +76,26 @@ void setup_hostinfo(char *buf, int len)
host.release, host.version, host.machine);
}
+/*
+ * We cannot use glibc's abort(). It makes use of tgkill() which
+ * has no effect within UML's kernel threads.
+ * After that glibc would execute an invalid instruction to kill
+ * the calling process and UML crashes with SIGSEGV.
+ */
+static inline void __attribute__ ((noreturn)) uml_abort(void)
+{
+ sigset_t sig;
+
+ fflush(NULL);
+
+ if (!sigemptyset(&sig) && !sigaddset(&sig, SIGABRT))
+ sigprocmask(SIG_UNBLOCK, &sig, 0);
+
+ for (;;)
+ if (kill(getpid(), SIGABRT) < 0)
+ exit(127);
+}
+
void os_dump_core(void)
{
int pid;
@@ -116,5 +137,5 @@ void os_dump_core(void)
while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0)
os_kill_ptraced_process(pid, 0);
- abort();
+ uml_abort();
}