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authorStanislaw Gruszka <stf_xl@wp.pl>2007-12-17 16:19:46 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-12-17 19:28:15 -0800
commit4dbed85a35ed37d9608f4f32e5d69efa775d6223 (patch)
tree67ab558db8ccaf8d706a25e5ce87b78be241cffb /arch/um/drivers
parent5867a78f41f84e5388448da62c183255dc22601f (diff)
downloadop-kernel-dev-4dbed85a35ed37d9608f4f32e5d69efa775d6223.zip
op-kernel-dev-4dbed85a35ed37d9608f4f32e5d69efa775d6223.tar.gz
uml: stop gdb from deleting breakpoints when running UML
Sometimes when UML is debugged gdb miss breakpoints. When process traced by gdb do fork, debugger remove breakpoints from child address space. There is possibility to trace more than one fork, but this not work with UML, I guess (only guess) there is a deadlock - gdb waits for UML and UML waits for gdb. When clone() is called with SIGCHLD and CLONE_VM flags, gdb see this as PTRACE_EVENT_FORK not as PTRACE_EVENT_CLONE and remove breakpoints from child and at the same time from traced process, because either have the same address space. Maybe it is possible to do fix in gdb, but I'm not sure if there is easy way to find out if traced and child processes share memory. So I do fix for UML, it simply do not call clone() with both SIGCHLD and CLONE_VM flags together. Additionally __WALL flag is used for waitpid() to assure not miss clone and normal process events. [ jdike - checkpatch fixes ] Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/um/drivers')
-rw-r--r--arch/um/drivers/net_user.c2
-rw-r--r--arch/um/drivers/slip_user.c12
-rw-r--r--arch/um/drivers/slirp_user.c15
-rw-r--r--arch/um/drivers/ubd_user.c3
4 files changed, 7 insertions, 25 deletions
diff --git a/arch/um/drivers/net_user.c b/arch/um/drivers/net_user.c
index 90d7f2e..29185ca 100644
--- a/arch/um/drivers/net_user.c
+++ b/arch/um/drivers/net_user.c
@@ -201,7 +201,7 @@ static int change_tramp(char **argv, char *output, int output_len)
close(fds[1]);
if (pid > 0)
- CATCH_EINTR(err = waitpid(pid, NULL, 0));
+ helper_wait(pid, 0, "change_tramp");
return pid;
}
diff --git a/arch/um/drivers/slip_user.c b/arch/um/drivers/slip_user.c
index 5f06204..b8711e5 100644
--- a/arch/um/drivers/slip_user.c
+++ b/arch/um/drivers/slip_user.c
@@ -77,7 +77,7 @@ static int slip_tramp(char **argv, int fd)
{
struct slip_pre_exec_data pe_data;
char *output;
- int status, pid, fds[2], err, output_len;
+ int pid, fds[2], err, output_len;
err = os_pipe(fds, 1, 0);
if (err < 0) {
@@ -109,15 +109,7 @@ static int slip_tramp(char **argv, int fd)
read_output(fds[0], output, output_len);
printk("%s", output);
- CATCH_EINTR(err = waitpid(pid, &status, 0));
- if (err < 0)
- err = errno;
- else if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0)) {
- printk(UM_KERN_ERR "'%s' didn't exit with status 0\n", argv[0]);
- err = -EINVAL;
- }
- else err = 0;
-
+ err = helper_wait(pid, 0, argv[0]);
close(fds[0]);
out_free:
diff --git a/arch/um/drivers/slirp_user.c b/arch/um/drivers/slirp_user.c
index 1865089..89c1be2 100644
--- a/arch/um/drivers/slirp_user.c
+++ b/arch/um/drivers/slirp_user.c
@@ -79,7 +79,7 @@ out:
static void slirp_close(int fd, void *data)
{
struct slirp_data *pri = data;
- int status,err;
+ int err;
close(fd);
close(pri->slave);
@@ -98,18 +98,9 @@ static void slirp_close(int fd, void *data)
"(%d)\n", pri->pid, errno);
}
#endif
-
- CATCH_EINTR(err = waitpid(pri->pid, &status, WNOHANG));
- if (err < 0) {
- printk(UM_KERN_ERR "slirp_close: waitpid returned %d\n", errno);
- return;
- }
-
- if (err == 0) {
- printk(UM_KERN_ERR "slirp_close: process %d has not exited\n",
- pri->pid);
+ err = helper_wait(pri->pid, 1, "slirp_close");
+ if (err < 0)
return;
- }
pri->pid = -1;
}
diff --git a/arch/um/drivers/ubd_user.c b/arch/um/drivers/ubd_user.c
index 41d254b..48fc745 100644
--- a/arch/um/drivers/ubd_user.c
+++ b/arch/um/drivers/ubd_user.c
@@ -49,8 +49,7 @@ int start_io_thread(unsigned long sp, int *fd_out)
goto out_close;
}
- pid = clone(io_thread, (void *) sp, CLONE_FILES | CLONE_VM | SIGCHLD,
- NULL);
+ pid = clone(io_thread, (void *) sp, CLONE_FILES | CLONE_VM, NULL);
if(pid < 0){
err = -errno;
printk("start_io_thread - clone failed : errno = %d\n", errno);
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