Re: pinpointed: PANIC caused by dequeue_signal() in current Linus BK tree

From: Ingo Molnar (mingo@elte.hu)
Date: Sun Sep 08 2002 - 21:45:12 EST

the attached patch fixes the bootup crash. There were two initialization
bugs:

        - INIT_SIGNAL needs to set shared_pending.

        - exec() needs to set up newsig properly.

the second one caused the crash Anton saw.

        Ingo

--- linux/arch/i386/kernel/init_task.c.orig Mon Sep 9 04:04:01 2002
+++ linux/arch/i386/kernel/init_task.c Mon Sep 9 04:04:35 2002
@@ -10,7 +10,7 @@
 
 static struct fs_struct init_fs = INIT_FS;
 static struct files_struct init_files = INIT_FILES;
-static struct signal_struct init_signals = INIT_SIGNALS;
+static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
 struct mm_struct init_mm = INIT_MM(init_mm);
 
 /*
--- linux/include/linux/init_task.h.orig Mon Sep 9 04:02:19 2002
+++ linux/include/linux/init_task.h Mon Sep 9 04:08:08 2002
@@ -29,10 +29,11 @@
         .mmlist = LIST_HEAD_INIT(name.mmlist), \
 }
 
-#define INIT_SIGNALS { \
+#define INIT_SIGNALS(sig) { \
         .count = ATOMIC_INIT(1), \
         .action = { {{0,}}, }, \
- .siglock = SPIN_LOCK_UNLOCKED \
+ .siglock = SPIN_LOCK_UNLOCKED, \
+ .shared_pending = { NULL, &sig.shared_pending.head, {{0}}}, \
 }
 
 /*
--- linux/fs/exec.c.orig Mon Sep 9 04:40:49 2002
+++ linux/fs/exec.c Mon Sep 9 04:41:28 2002
@@ -514,6 +514,8 @@
         spin_lock_init(&newsig->siglock);
         atomic_set(&newsig->count, 1);
         memcpy(newsig->action, current->sig->action, sizeof(newsig->action));
+ init_sigpending(&newsig->shared_pending);
+
         spin_lock_irq(&current->sigmask_lock);
         current->sig = newsig;
         spin_unlock_irq(&current->sigmask_lock);

-
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This archive was generated by hypermail 2b29 : Sun Sep 15 2002 - 22:00:15 EST