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authorMark Rutland <mark.rutland@arm.com>2019-01-10 14:27:45 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-02-12 19:47:26 +0100
commit1aeeb176683db86248656c3b62f1ae0ce4fbdba5 (patch)
tree41d5d60f45cf73d330dbf0231b978d1ed2a08459
parent5b27e3bc5a2bdf58ff0aedacd194c3ed86821f07 (diff)
downloadlinux-linaro-stable-1aeeb176683db86248656c3b62f1ae0ce4fbdba5.tar.gz
perf/core: Don't WARN() for impossible ring-buffer sizes
commit 9dff0aa95a324e262ffb03f425d00e4751f3294e upstream. The perf tool uses /proc/sys/kernel/perf_event_mlock_kb to determine how large its ringbuffer mmap should be. This can be configured to arbitrary values, which can be larger than the maximum possible allocation from kmalloc. When this is configured to a suitably large value (e.g. thanks to the perf fuzzer), attempting to use perf record triggers a WARN_ON_ONCE() in __alloc_pages_nodemask(): WARNING: CPU: 2 PID: 5666 at mm/page_alloc.c:4511 __alloc_pages_nodemask+0x3f8/0xbc8 Let's avoid this by checking that the requested allocation is possible before calling kzalloc. Reported-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20190110142745.25495-1-mark.rutland@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/events/ring_buffer.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 5d3cf407e374..51386d9105fa 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -724,6 +724,9 @@ struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
size = sizeof(struct ring_buffer);
size += nr_pages * sizeof(void *);
+ if (order_base_2(size) >= MAX_ORDER)
+ goto fail;
+
rb = kzalloc(size, GFP_KERNEL);
if (!rb)
goto fail;