The patch titled
Subject: signal: introduce kernel_signal_stop() to fix jffs2_garbage_collect_thread()
has been added to the -mm tree. Its filename is
signal-introduce-kernel_signal_stop-to-fix-jffs2_garbage_collect_thread.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/signal-introduce-kernel_signal_stop-to-fix-jffs2_garbage_collect_thread.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/signal-introduce-kernel_signal_stop-to-fix-jffs2_garbage_collect_thread.patch
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------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: signal: introduce kernel_signal_stop() to fix jffs2_garbage_collect_thread()
jffs2_garbage_collect_thread() can race with SIGCONT and sleep in
TASK_STOPPED state after it was already sent. Add the new helper,
kernel_signal_stop(), which does this correctly.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Reviewed-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Felipe Balbi <balbi@xxxxxx>
Cc: Markus Pargmann <mpa@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/jffs2/background.c | 3 +--
include/linux/sched.h | 10 ++++++++++
2 files changed, 11 insertions(+), 2 deletions(-)
diff -puN fs/jffs2/background.c~signal-introduce-kernel_signal_stop-to-fix-jffs2_garbage_collect_thread fs/jffs2/background.c
--- a/fs/jffs2/background.c~signal-introduce-kernel_signal_stop-to-fix-jffs2_garbage_collect_thread
+++ a/fs/jffs2/background.c
@@ -132,8 +132,7 @@ static int jffs2_garbage_collect_thread(
case SIGSTOP:
jffs2_dbg(1, "%s(): SIGSTOP received\n",
__func__);
- set_current_state(TASK_STOPPED);
- schedule();
+ kernel_signal_stop();
break;
case SIGKILL:
diff -puN include/linux/sched.h~signal-introduce-kernel_signal_stop-to-fix-jffs2_garbage_collect_thread include/linux/sched.h
--- a/include/linux/sched.h~signal-introduce-kernel_signal_stop-to-fix-jffs2_garbage_collect_thread
+++ a/include/linux/sched.h
@@ -2477,6 +2477,16 @@ static inline int kernel_dequeue_signal(
return ret;
}
+static inline void kernel_signal_stop(void)
+{
+ spin_lock_irq(¤t->sighand->siglock);
+ if (current->jobctl & JOBCTL_STOP_DEQUEUED)
+ __set_current_state(TASK_STOPPED);
+ spin_unlock_irq(¤t->sighand->siglock);
+
+ schedule();
+}
+
extern void release_task(struct task_struct * p);
extern int send_sig_info(int, struct siginfo *, struct task_struct *);
extern int force_sigsegv(int, struct task_struct *);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
mm-fix-the-racy-mm-locked_vm-change-in.patch
mm-add-the-struct-mm_struct-mm-local-into.patch
mm-oom_kill-remove-the-wrong-fatal_signal_pending-check-in-oom_kill_process.patch
mm-oom_kill-cleanup-the-kill-sharing-same-memory-loop.patch
mm-oom_kill-fix-the-wrong-task-mm-==-mm-checks-in-oom_kill_process.patch
change-current_is_single_threaded-to-use-for_each_thread.patch
signals-kill-block_all_signals-and-unblock_all_signals.patch
signal-turn-dequeue_signal_lock-into-kernel_dequeue_signal.patch
signal-introduce-kernel_signal_stop-to-fix-jffs2_garbage_collect_thread.patch
signal-remove-jffs2_garbage_collect_thread-allow_signalsigcont.patch
coredump-ensure-all-coredumping-tasks-have-signal_group_coredump.patch
coredump-change-zap_threads-and-zap_process-to-use-for_each_thread.patch
--
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