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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/os-Linux/drivers
parent5867a78f41f84e5388448da62c183255dc22601f (diff)
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/os-Linux/drivers')
-rw-r--r--arch/um/os-Linux/drivers/ethertap_user.c10
-rw-r--r--arch/um/os-Linux/drivers/tuntap_user.c2
2 files changed, 3 insertions, 9 deletions
diff --git a/arch/um/os-Linux/drivers/ethertap_user.c b/arch/um/os-Linux/drivers/ethertap_user.c
index 4ff55360344..07ca0cb472a 100644
--- a/arch/um/os-Linux/drivers/ethertap_user.c
+++ b/arch/um/os-Linux/drivers/ethertap_user.c
@@ -94,7 +94,7 @@ static int etap_tramp(char *dev, char *gate, int control_me,
int control_remote, int data_me, int data_remote)
{
struct etap_pre_exec_data pe_data;
- int pid, status, err, n;
+ int pid, err, n;
char version_buf[sizeof("nnnnn\0")];
char data_fd_buf[sizeof("nnnnnn\0")];
char gate_buf[sizeof("nnn.nnn.nnn.nnn\0")];
@@ -131,13 +131,7 @@ static int etap_tramp(char *dev, char *gate, int control_me,
}
if (c != 1) {
printk(UM_KERN_ERR "etap_tramp : uml_net failed\n");
- err = -EINVAL;
- CATCH_EINTR(n = waitpid(pid, &status, 0));
- if (n < 0)
- err = -errno;
- else if (!WIFEXITED(status) || (WEXITSTATUS(status) != 1))
- printk(UM_KERN_ERR "uml_net didn't exit with "
- "status 1\n");
+ err = helper_wait(pid, 0, "uml_net");
}
return err;
}
diff --git a/arch/um/os-Linux/drivers/tuntap_user.c b/arch/um/os-Linux/drivers/tuntap_user.c
index 6c55d3c8ead..1037a3b6386 100644
--- a/arch/um/os-Linux/drivers/tuntap_user.c
+++ b/arch/um/os-Linux/drivers/tuntap_user.c
@@ -107,7 +107,7 @@ static int tuntap_open_tramp(char *gate, int *fd_out, int me, int remote,
"errno = %d\n", errno);
return err;
}
- CATCH_EINTR(waitpid(pid, NULL, 0));
+ helper_wait(pid, 0, "tuntap_open_tramp");
cmsg = CMSG_FIRSTHDR(&msg);
if (cmsg == NULL) {