On Wed, 2007-02-21 at 16:53 +0100, Arjan van de Ven wrote:

quoted

Index: linux-2.6-git/kernel/softirq.c
===================================================================

--- linux-2.6-git.orig/kernel/softirq.c	2006-12-14 10:02:18.000000000 +0100
+++ linux-2.6-git/kernel/softirq.c	2006-12-14 10:02:52.000000000 +0100

@@ -209,6 +209,8 @@ asmlinkage void __do_softirq(void)
 	__u32 pending;
 	int max_restart = MAX_SOFTIRQ_RESTART;
 	int cpu;
+	unsigned long pflags = current->flags;
+	current->flags &= ~PF_MEMALLOC;
 
 	pending = local_softirq_pending();
 	account_system_vtime(current);

@@ -247,6 +249,7 @@ restart:
 
 	account_system_vtime(current);
 	_local_bh_enable();
+	current->flags = pflags;

this wipes out all the flags in one go.... evil.
What if something just selected this process for OOM killing? you nuke
that flag here again. Would be nicer if only the PF_MEMALLOC bit got
inherited in the restore path..

would something like this:

#define PF_PUSH(tsk, pflags, mask)		\
do {						\
	(pflags) = ((tsk)->flags) & (mask);	\
} while (0)


#define PF_POP(tsk, pflags, mask)		\
do {						\
	((tsk)->flags &= ~(mask);		\
	((tsk)->flags |= (pflags);		\
} while (0)

be useful, or shall I just open code it in various places?

(I made this same mistake; ignorant of the problem; all over this patch series)