4.7-stable review patch. If anyone has any objections, please let me know.
------------------
From: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
commit 4b3ec5a3f4b1d5c9d64b9ab704042400d050d432 upstream.
Currently we call quarantine_reduce() for ___GFP_KSWAPD_RECLAIM (implied
by __GFP_RECLAIM) allocation. So, basically we call it on almost every
allocation. quarantine_reduce() sometimes is heavy operation, and
calling it with disabled interrupts may trigger hard LOCKUP:
NMI watchdog: Watchdog detected hard LOCKUP on cpu 2irq event stamp: 1411258
Call Trace:
<NMI> dump_stack+0x68/0x96
watchdog_overflow_callback+0x15b/0x190
__perf_event_overflow+0x1b1/0x540
perf_event_overflow+0x14/0x20
intel_pmu_handle_irq+0x36a/0xad0
perf_event_nmi_handler+0x2c/0x50
nmi_handle+0x128/0x480
default_do_nmi+0xb2/0x210
do_nmi+0x1aa/0x220
end_repeat_nmi+0x1a/0x1e
<<EOE>> __kernel_text_address+0x86/0xb0
print_context_stack+0x7b/0x100
dump_trace+0x12b/0x350
save_stack_trace+0x2b/0x50
set_track+0x83/0x140
free_debug_processing+0x1aa/0x420
__slab_free+0x1d6/0x2e0
___cache_free+0xb6/0xd0
qlist_free_all+0x83/0x100
quarantine_reduce+0x177/0x1b0
kasan_kmalloc+0xf3/0x100
Reduce the quarantine_reduce iff direct reclaim is allowed.
Fixes: 55834c59098d("mm: kasan: initial memory quarantine implementation")
Link: http://lkml.kernel.org/r/1470062715-14077-2-git-send-email-aryabinin@xxxxxxxxxxxxx
Signed-off-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Reported-by: Dave Jones <davej@xxxxxxxxxxxxxxxxx>
Acked-by: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/kasan/kasan.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -562,7 +562,7 @@ void kasan_kmalloc(struct kmem_cache *ca
unsigned long redzone_start;
unsigned long redzone_end;
- if (flags & __GFP_RECLAIM)
+ if (gfpflags_allow_blocking(flags))
quarantine_reduce();
if (unlikely(object == NULL))
@@ -595,7 +595,7 @@ void kasan_kmalloc_large(const void *ptr
unsigned long redzone_start;
unsigned long redzone_end;
- if (flags & __GFP_RECLAIM)
+ if (gfpflags_allow_blocking(flags))
quarantine_reduce();
if (unlikely(ptr == NULL))
--
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