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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 19:45:01 +0100
commit9269ba3cb74c97cea89c9347042a0d89e4f4b0fc (patch)
tree9e15f2029caf8a38acbf73e8fb035611fd26608e
parentc2e3f4e632991fa8b6e8f00aae6ae0cb635bd67b (diff)
downloadlinux-linaro-stable-9269ba3cb74c97cea89c9347042a0d89e4f4b0fc.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 017f7933a37d..f4b5811ebe23 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -700,6 +700,9 @@ 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;