diff options
| author |   visa <visa@openbsd.org> | 2020-03-18 15:48:21 +0000 |
|---|---|---|
| committer | visa <visa@openbsd.org> | 2020-03-18 15:48:21 +0000 |
| commit | 19d4244da751ce8223f33a98ff39833f0404cc1e (patch) | |
| tree | 3ecf07e6418cf6d5243b4382eec5946f16007906 | |
| parent | Plug mem leak in SADB_REGISTER. (diff) | |
| download | wireguard-openbsd-19d4244da751ce8223f33a98ff39833f0404cc1e.tar.xz wireguard-openbsd-19d4244da751ce8223f33a98ff39833f0404cc1e.zip | |
Restart child process scan in dowait4() if single_thread_wait() sleeps.
This ensures that the conditions checked are still in force. The sleep
breaks atomicity, allowing another thread to alter the state.
single_thread_set() should return immediately after sleep when called
from dowait4() because there is no guarantee that the process pr still
exists. When called from single_thread_set(), the process is that of
the calling thread, which prevents process pr from disappearing.
OK anton@, mpi@, claudio@
| -rw-r--r-- | sys/kern/kern_exit.c | 5 | ||||
| -rw-r--r-- | sys/kern/kern_sig.c | 18 | ||||
| -rw-r--r-- | sys/sys/proc.h | 4 |
3 files changed, 18 insertions, 9 deletions
diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c index 1ed8f8f3474..66ffad0de02 100644 --- a/sys/kern/kern_exit.c +++ b/sys/kern/kern_exit.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kern_exit.c,v 1.187 2020/03/16 11:58:46 mpi Exp $ */ +/* $OpenBSD: kern_exit.c,v 1.188 2020/03/18 15:48:21 visa Exp $ */ /* $NetBSD: kern_exit.c,v 1.39 1996/04/22 01:38:25 christos Exp $ */ /* @@ -539,7 +539,8 @@ loop: (pr->ps_flags & PS_WAITED) == 0 && pr->ps_single && pr->ps_single->p_stat == SSTOP && (pr->ps_single->p_flag & P_SUSPSINGLE) == 0) { - single_thread_wait(pr); + if (single_thread_wait(pr, 0)) + goto loop; atomic_setbits_int(&pr->ps_flags, PS_WAITED); retval[0] = pr->ps_pid; diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c index 07a519e680b..9caba3240d4 100644 --- a/sys/kern/kern_sig.c +++ b/sys/kern/kern_sig.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kern_sig.c,v 1.253 2020/03/13 09:25:21 mpi Exp $ */ +/* $OpenBSD: kern_sig.c,v 1.254 2020/03/18 15:48:21 visa Exp $ */ /* $NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $ */ /* @@ -2024,17 +2024,25 @@ single_thread_set(struct proc *p, enum single_thread_mode mode, int deep) } if (mode != SINGLE_PTRACE) - single_thread_wait(pr); + single_thread_wait(pr, 1); return 0; } -void -single_thread_wait(struct process *pr) +int +single_thread_wait(struct process *pr, int recheck) { + int waited = 0; + /* wait until they're all suspended */ - while (pr->ps_singlecount > 0) + while (pr->ps_singlecount > 0) { tsleep_nsec(&pr->ps_singlecount, PWAIT, "suspend", INFSLP); + waited = 1; + if (!recheck) + break; + } + + return waited; } void diff --git a/sys/sys/proc.h b/sys/sys/proc.h index d685dd71365..5378afa7717 100644 --- a/sys/sys/proc.h +++ b/sys/sys/proc.h @@ -1,4 +1,4 @@ -/* $OpenBSD: proc.h,v 1.290 2020/03/16 11:58:46 mpi Exp $ */ +/* $OpenBSD: proc.h,v 1.291 2020/03/18 15:48:22 visa Exp $ */ /* $NetBSD: proc.h,v 1.44 1996/04/22 01:23:21 christos Exp $ */ /*- @@ -614,7 +614,7 @@ enum single_thread_mode { SINGLE_EXIT /* other threads to unwind and then exit */ }; int single_thread_set(struct proc *, enum single_thread_mode, int); -void single_thread_wait(struct process *); +int single_thread_wait(struct process *, int); void single_thread_clear(struct proc *, int); int single_thread_check(struct proc *, int); |