- printk-should-not-be-called-under-zone-lock.patch removed from -mm tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



The patch titled

     printk() should not be called under zone->lock

has been removed from the -mm tree.  Its filename is

     printk-should-not-be-called-under-zone-lock.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
Subject: printk() should not be called under zone->lock
From: Kirill Korotaev <dev@xxxxxxxxxx>


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@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---

 mm/page_alloc.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff -puN mm/page_alloc.c~printk-should-not-be-called-under-zone-lock mm/page_alloc.c
--- a/mm/page_alloc.c~printk-should-not-be-called-under-zone-lock
+++ a/mm/page_alloc.c
@@ -1491,7 +1491,7 @@ void show_free_areas(void)
 	}
 
 	for_each_zone(zone) {
- 		unsigned long nr, flags, order, total = 0;
+ 		unsigned long nr[MAX_ORDER], flags, order, total = 0;
 
 		show_node(zone);
 		printk("%s: ", zone->name);
@@ -1502,11 +1502,12 @@ void show_free_areas(void)
 
 		spin_lock_irqsave(&zone->lock, flags);
 		for (order = 0; order < MAX_ORDER; order++) {
-			nr = zone->free_area[order].nr_free;
-			total += nr << order;
-			printk("%lu*%lukB ", nr, K(1UL) << order);
+			nr[order] = zone->free_area[order].nr_free;
+			total += nr[order] << order;
 		}
 		spin_unlock_irqrestore(&zone->lock, flags);
+		for (order = 0; order < MAX_ORDER; order++)
+			printk("%lu*%lukB ", nr[order], K(1UL) << order);
 		printk("= %lukB\n", K(total));
 	}
 
_

Patches currently in -mm which might be from dev@xxxxxxxxxx are

origin.patch
proc-sysctl-add-_proc_do_string-helper.patch
namespaces-add-nsproxy.patch
namespaces-add-nsproxy-dont-include-compileh.patch
namespaces-incorporate-fs-namespace-into-nsproxy.patch
namespaces-utsname-introduce-temporary-helpers.patch
namespaces-utsname-switch-to-using-uts-namespaces.patch
namespaces-utsname-switch-to-using-uts-namespaces-alpha-fix.patch
namespaces-utsname-switch-to-using-uts-namespaces-cleanup.patch
namespaces-utsname-use-init_utsname-when-appropriate.patch
namespaces-utsname-use-init_utsname-when-appropriate-cifs-update.patch
namespaces-utsname-implement-utsname-namespaces.patch
namespaces-utsname-implement-utsname-namespaces-export.patch
namespaces-utsname-implement-utsname-namespaces-dont-include-compileh.patch
namespaces-utsname-sysctl-hack.patch
namespaces-utsname-sysctl-hack-cleanup.patch
namespaces-utsname-sysctl-hack-cleanup-2.patch
namespaces-utsname-sysctl-hack-cleanup-2-fix.patch
namespaces-utsname-remove-system_utsname.patch
namespaces-utsname-implement-clone_newuts-flag.patch
uts-copy-nsproxy-only-when-needed.patch
ipc-namespace-core.patch
ipc-namespace-core-fix.patch
ipc-namespace-core-unshare-fix.patch
ipc-namespace-utils.patch
ipc-namespace-msg.patch
ipc-namespace-sem.patch
ipc-namespace-shm.patch
ipc-namespace-sysctls.patch

-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Kernel Newbies FAQ]     [Kernel Archive]     [IETF Annouce]     [DCCP]     [Netdev]     [Networking]     [Security]     [Bugtraq]     [Photo]     [Yosemite]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux SCSI]

  Powered by Linux