[PATCH 5/5] UML - Stack consumption reduction

From: Jeff Dike
Date: Wed Sep 27 2006 - 13:59:32 EST


Fix some stack abuse in the sysrq t path.

Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxx>
---

arch/um/drivers/mconsole_kern.c | 15 ++++++++++-----
arch/um/drivers/mconsole_user.c | 4 ++++
2 files changed, 14 insertions(+), 5 deletions(-)

Index: linux-2.6.18-mm/arch/um/drivers/mconsole_kern.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/drivers/mconsole_kern.c 2006-09-26 16:28:51.000000000 -0400
+++ linux-2.6.18-mm/arch/um/drivers/mconsole_kern.c 2006-09-26 16:39:37.000000000 -0400
@@ -598,6 +598,11 @@ out:
mconsole_reply(req, err_msg, err, 0);
}

+struct mconsole_output {
+ struct list_head list;
+ struct mc_request *req;
+};
+
static DEFINE_SPINLOCK(console_lock);
static LIST_HEAD(clients);
static char console_buf[MCONSOLE_MAX_DATA];
@@ -622,10 +627,10 @@ static void console_write(struct console
return;

list_for_each(ele, &clients){
- struct mconsole_entry *entry;
+ struct mconsole_output *entry;

- entry = list_entry(ele, struct mconsole_entry, list);
- mconsole_reply_len(&entry->request, console_buf,
+ entry = list_entry(ele, struct mconsole_output, list);
+ mconsole_reply_len(entry->req, console_buf,
console_index, 0, 1);
}

@@ -649,10 +654,10 @@ late_initcall(mc_add_console);
static void with_console(struct mc_request *req, void (*proc)(void *),
void *arg)
{
- struct mconsole_entry entry;
+ struct mconsole_output entry;
unsigned long flags;

- entry.request = *req;
+ entry.req = req;
list_add(&entry.list, &clients);
spin_lock_irqsave(&console_lock, flags);

Index: linux-2.6.18-mm/arch/um/drivers/mconsole_user.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/drivers/mconsole_user.c 2006-09-26 16:28:51.000000000 -0400
+++ linux-2.6.18-mm/arch/um/drivers/mconsole_user.c 2006-09-26 16:39:37.000000000 -0400
@@ -131,6 +131,10 @@ int mconsole_get_request(int fd, struct
int mconsole_reply_len(struct mc_request *req, const char *str, int total,
int err, int more)
{
+ /* XXX This is a stack consumption problem. It'd be nice to
+ * make it global and serialize access to it, but there are a
+ * ton of callers to this function.
+ */
struct mconsole_reply reply;
int len, n;


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