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| author | Al Viro <viro@zeniv.linux.org.uk> | 2017-07-08 11:26:39 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2017-07-08 11:26:39 -0400 |
| commit | 634a81609561f05266e1f625b6f2567c2e0b0419 (patch) | |
| tree | 142d5a227bad78810a989b8daa6ff47d637b9a60 /kernel | |
| parent | da029c11e6b12f321f36dac8771e833b65cec962 (diff) | |
| download | lwn-634a81609561f05266e1f625b6f2567c2e0b0419.tar.gz lwn-634a81609561f05266e1f625b6f2567c2e0b0419.zip | |
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: Markus Trippelsdorf <markus@trippelsdorf.de>
Fixes: 67d7ddded322 ("waitid(2): leave copyout of siginfo to syscall itself")
Tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/exit.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 2bbc23273e2f..608c9775a37b 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -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); |