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authorKirill Korotaev <dev@openvz.org>2006-06-23 05:03:50 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-23 10:42:52 -0400
commit8f9de51a4a98ba32f839903b7d009788bc2c295d (patch)
tree65cde3cd75bfc1df172f53ca956cba4fa4954a4e /mm/page_alloc.c
parentd501e62bc7796e90b0312648e23ac39490dfbf87 (diff)
[PATCH] printk() should not be called under zone->lock
This patch fixes printk() under zone->lock in show_free_areas(). It can be unsafe to call printk() under this lock, since caller can try to allocate/free some memory and selfdeadlock on this lock. I found allocations/freeing mem both in netconsole and serial console. This issue was faced in reallity when meminfo was periodically printed for debug purposes and netconsole was used. Signed-off-by: Kirill Korotaev <dev@openvz.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 71a0b2a23f5b..423db0db7c02 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1491,7 +1491,7 @@ void show_free_areas(void)
1491 } 1491 }
1492 1492
1493 for_each_zone(zone) { 1493 for_each_zone(zone) {
1494 unsigned long nr, flags, order, total = 0; 1494 unsigned long nr[MAX_ORDER], flags, order, total = 0;
1495 1495
1496 show_node(zone); 1496 show_node(zone);
1497 printk("%s: ", zone->name); 1497 printk("%s: ", zone->name);
@@ -1502,11 +1502,12 @@ void show_free_areas(void)
1502 1502
1503 spin_lock_irqsave(&zone->lock, flags); 1503 spin_lock_irqsave(&zone->lock, flags);
1504 for (order = 0; order < MAX_ORDER; order++) { 1504 for (order = 0; order < MAX_ORDER; order++) {
1505 nr = zone->free_area[order].nr_free; 1505 nr[order] = zone->free_area[order].nr_free;
1506 total += nr << order; 1506 total += nr[order] << order;
1507 printk("%lu*%lukB ", nr, K(1UL) << order);
1508 } 1507 }
1509 spin_unlock_irqrestore(&zone->lock, flags); 1508 spin_unlock_irqrestore(&zone->lock, flags);
1509 for (order = 0; order < MAX_ORDER; order++)
1510 printk("%lu*%lukB ", nr[order], K(1UL) << order);
1510 printk("= %lukB\n", K(total)); 1511 printk("= %lukB\n", K(total));
1511 } 1512 }
1512 1513