Commit 634a8160 authored by Al Viro's avatar Al Viro
Browse files

fix waitid(2) breakage 



We lose the distinction between "found a PID" and "nothing, but that's not
an error" a bit too early in waitid().  Easily fixed, fortunately...

Reported-by: default avatarMarkus Trippelsdorf <markus@trippelsdorf.de>
Fixes: 67d7ddde ("waitid(2): leave copyout of siginfo to syscall itself")
Tested-by: default avatarMarkus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent da029c11

kernel/exit.c

+12 −5
Original line number Diff line number Diff line
@@ -1590,9 +1590,6 @@ static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop, 
	wo.wo_rusage	= ru;

	ret = do_wait(&wo);



	if (ret > 0)

		ret = 0;



	put_pid(pid);

	return ret;

}
@@ -1603,6 +1600,11 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *, 
	struct rusage r;

	struct waitid_info info = {.status = 0};

	long err = kernel_waitid(which, upid, &info, options, ru ? &r : NULL);

	int signo = 0;

	if (err > 0) {

		signo = SIGCHLD;

		err = 0;

	}



	if (!err) {

		if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
@@ -1612,7 +1614,7 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *, 
		return err;



	user_access_begin();

	unsafe_put_user(err ? 0 : SIGCHLD, &infop->si_signo, Efault);

	unsafe_put_user(signo, &infop->si_signo, Efault);

	unsafe_put_user(0, &infop->si_errno, Efault);

	unsafe_put_user((short)info.cause, &infop->si_code, Efault);

	unsafe_put_user(info.pid, &infop->si_pid, Efault);
@@ -1714,6 +1716,11 @@ COMPAT_SYSCALL_DEFINE5(waitid, 
	struct rusage ru;

	struct waitid_info info = {.status = 0};

	long err = kernel_waitid(which, pid, &info, options, uru ? &ru : NULL);

	int signo = 0;

	if (err > 0) {

		signo = SIGCHLD;

		err = 0;

	}



	if (!err && uru) {

		/* kernel_waitid() overwrites everything in ru */
@@ -1729,7 +1736,7 @@ COMPAT_SYSCALL_DEFINE5(waitid, 
		return err;



	user_access_begin();

	unsafe_put_user(err ? 0 : SIGCHLD, &infop->si_signo, Efault);

	unsafe_put_user(signo, &infop->si_signo, Efault);

	unsafe_put_user(0, &infop->si_errno, Efault);

	unsafe_put_user((short)info.cause, &infop->si_code, Efault);

	unsafe_put_user(info.pid, &infop->si_pid, Efault);

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