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| author | Linus Walleij <linus.walleij@linaro.org> | 2015-01-30 10:38:15 +0100 |
|---|---|---|
| committer | Linus Walleij <linus.walleij@linaro.org> | 2015-01-30 10:38:15 +0100 |
| commit | b6afdbe8e841e20297a38e2af0a053d8eb26c19b (patch) | |
| tree | 4a336799dcd7d77a7d1f1e9b46b9e48551053524 /kernel/exit.c | |
| parent | 8090f7917b5d7cc2390afe33cb12f819173ef9c8 (diff) | |
| parent | 26bc420b59a38e4e6685a73345a0def461136dce (diff) | |
Merge tag 'v3.19-rc6' into devel
Linux 3.19-rc6
Diffstat (limited to 'kernel/exit.c')
| -rw-r--r-- | kernel/exit.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 1ea4369890a3..6806c55475ee 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1287,9 +1287,15 @@ static int wait_task_continued(struct wait_opts *wo, struct task_struct *p) static int wait_consider_task(struct wait_opts *wo, int ptrace, struct task_struct *p) { + /* + * We can race with wait_task_zombie() from another thread. + * Ensure that EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE transition + * can't confuse the checks below. + */ + int exit_state = ACCESS_ONCE(p->exit_state); int ret; - if (unlikely(p->exit_state == EXIT_DEAD)) + if (unlikely(exit_state == EXIT_DEAD)) return 0; ret = eligible_child(wo, p); @@ -1310,7 +1316,7 @@ static int wait_consider_task(struct wait_opts *wo, int ptrace, return 0; } - if (unlikely(p->exit_state == EXIT_TRACE)) { + if (unlikely(exit_state == EXIT_TRACE)) { /* * ptrace == 0 means we are the natural parent. In this case * we should clear notask_error, debugger will notify us. @@ -1337,7 +1343,7 @@ static int wait_consider_task(struct wait_opts *wo, int ptrace, } /* slay zombie? */ - if (p->exit_state == EXIT_ZOMBIE) { + if (exit_state == EXIT_ZOMBIE) { /* we don't reap group leaders with subthreads */ if (!delay_group_leader(p)) { /* |