The patch titled
oom: fix constraint deadlock
has been added to the -mm tree. Its filename is
oom-fix-constraint-deadlock.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: oom: fix constraint deadlock
From: David Rientjes <rientjes@xxxxxxxxxx>
Fixes a deadlock in the OOM killer for allocations that are not
__GFP_HARDWALL.
Before the OOM killer checks for the allocation constraint, it takes
callback_mutex.
constrained_alloc() iterates through each zone in the allocation zonelist
and calls cpuset_zone_allowed_softwall() to determine whether an allocation
for gfp_mask is possible. If a zone's node is not in the OOM-triggering
task's mems_allowed, it is not exiting, and we did not fail on a
__GFP_HARDWALL allocation, cpuset_zone_allowed_softwall() attempts to take
callback_mutex to check the nearest exclusive ancestor of current's cpuset.
This results in deadlock.
We now take callback_mutex after iterating through the zonelist since we
don't need it yet.
Cc: Andi Kleen <ak@xxxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxx>
Cc: Christoph Lameter <clameter@xxxxxxxxxxxx>
Cc: Martin J. Bligh <mbligh@xxxxxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/oom_kill.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff -puN mm/oom_kill.c~oom-fix-constraint-deadlock mm/oom_kill.c
--- a/mm/oom_kill.c~oom-fix-constraint-deadlock
+++ a/mm/oom_kill.c
@@ -399,6 +399,7 @@ void out_of_memory(struct zonelist *zone
struct task_struct *p;
unsigned long points = 0;
unsigned long freed = 0;
+ int constraint;
blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
if (freed > 0)
@@ -416,14 +417,15 @@ void out_of_memory(struct zonelist *zone
if (sysctl_panic_on_oom == 2)
panic("out of memory. Compulsory panic_on_oom is selected.\n");
- cpuset_lock();
- read_lock(&tasklist_lock);
-
/*
* Check if there were limitations on the allocation (only relevant for
* NUMA) that may require different handling.
*/
- switch (constrained_alloc(zonelist, gfp_mask)) {
+ constraint = constrained_alloc(zonelist, gfp_mask);
+ cpuset_lock();
+ read_lock(&tasklist_lock);
+
+ switch (constraint) {
case CONSTRAINT_MEMORY_POLICY:
oom_kill_process(current, points,
"No available memory (MPOL_BIND)");
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
slab-x86_64-skip-cache_free_alien-on-non-numa.patch
i386-add-ptep_test_and_clear_dirtyyoung.patch
i386-use-pte_update_defer-in-ptep_test_and_clear_dirtyyoung.patch
i386-use-pte_update_defer-in-ptep_test_and_clear_dirtyyoung-fix.patch
smaps-extract-pmd-walker-from-smaps-code.patch
smaps-add-pages-referenced-count-to-smaps.patch
smaps-add-clear_refs-file-to-clear-reference.patch
smaps-add-clear_refs-file-to-clear-reference-fix.patch
smaps-add-clear_refs-file-to-clear-reference-fix-fix.patch
smaps-add-clear_refs-file-to-clear-reference-fix-fix-2.patch
smaps-add-clear_refs-file-to-clear-reference-cleanup.patch
smaps-use-ptep_test_and_clear_young.patch
smaps-add-clear_refs-file-to-clear-reference-docs.patch
maps2-uninline-some-functions-in-the-page-walker.patch
maps2-eliminate-the-pmd_walker-struct-in-the-page-walker.patch
maps2-remove-vma-from-args-in-the-page-walker.patch
maps2-propagate-errors-from-callback-in-page-walker.patch
maps2-add-callbacks-for-each-level-to-page-walker.patch
maps2-move-the-page-walker-code-to-lib.patch
maps2-move-the-page-walker-code-to-lib-fix.patch
maps2-simplify-interdependence-of-proc-pid-maps-and-smaps.patch
maps2-move-clear_refs-code-to-task_mmuc.patch
maps2-regroup-task_mmu-by-interface.patch
maps2-make-proc-pid-smaps-optional-under-config_embedded.patch
maps2-make-proc-pid-clear_refs-option-under-config_embedded.patch
maps2-add-proc-pid-pagemap-interface.patch
maps2-add-proc-kpagemap-interface.patch
cpusets-allow-tif_memdie-threads-to-allocate-anywhere.patch
mm-fix-handling-of-panic_on_oom-when-cpusets-are-in-use.patch
oom-fix-constraint-deadlock.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
