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authorJens Axboe <axboe@kernel.dk>2020-10-26 23:32:28 +0300
committerThomas Gleixner <tglx@linutronix.de>2020-10-29 11:37:36 +0300
commit12db8b690010ccfadf9d0b49a1e1798e47dbbe1a (patch)
tree185645b2e040fb94b3dfc06fae3c4f2ea8d734ad /kernel/signal.c
parent5c251e9dc0e127bac6fc5b8e6696363d2e35f515 (diff)
downloadlinux-12db8b690010ccfadf9d0b49a1e1798e47dbbe1a.tar.xz
entry: Add support for TIF_NOTIFY_SIGNAL
Add TIF_NOTIFY_SIGNAL handling in the generic entry code, which if set, will return true if signal_pending() is used in a wait loop. That causes an exit of the loop so that notify_signal tracehooks can be run. If the wait loop is currently inside a system call, the system call is restarted once task_work has been processed. In preparation for only having arch_do_signal() handle syscall restarts if _TIF_SIGPENDING isn't set, rename it to arch_do_signal_or_restart(). Pass in a boolean that tells the architecture specific signal handler if it should attempt to get a signal, or just process a potential syscall restart. For !CONFIG_GENERIC_ENTRY archs, add the TIF_NOTIFY_SIGNAL handling to get_signal(). This is done to minimize the needed architecture changes to support this feature. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Link: https://lore.kernel.org/r/20201026203230.386348-3-axboe@kernel.dk
Diffstat (limited to 'kernel/signal.c')
-rw-r--r--kernel/signal.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index b179eccc86d0..61b377e65c46 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2529,6 +2529,20 @@ bool get_signal(struct ksignal *ksig)
struct signal_struct *signal = current->signal;
int signr;
+ /*
+ * For non-generic architectures, check for TIF_NOTIFY_SIGNAL so
+ * that the arch handlers don't all have to do it. If we get here
+ * without TIF_SIGPENDING, just exit after running signal work.
+ */
+#ifdef TIF_NOTIFY_SIGNAL
+ if (!IS_ENABLED(CONFIG_GENERIC_ENTRY)) {
+ if (test_thread_flag(TIF_NOTIFY_SIGNAL))
+ tracehook_notify_signal();
+ if (!task_sigpending(current))
+ return false;
+ }
+#endif
+
if (unlikely(uprobe_deny_signal()))
return false;