Messages in this thread Patch in this message | | | From | Hendrik Brueckner <> | Subject | [PATCH] kernel/perf: correct return code of rb_alloc_aux() if !has_aux(ev) | Date | Tue, 20 Jun 2017 12:26:39 +0200 |
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If the event for which an AUX area is about to be allocated, does not support setting up an AUX area, rb_alloc_aux() return -ENOTSUPP.
This error condition is being returned unfiltered to the user space, and, for example, the perf tools fails with:
failed to mmap with 524 (INTERNAL ERROR: strerror_r(524, 0x3fff497a1c8, 512)=22)
This error can be easily seen with "perf record -m 128,256 -e cpu-clock".
The 524 error code maps to -ENOTSUPP (in rb_alloc_aux()). The -ENOTSUPP error code shall be only used within the kernel. So the correct error code would then be -EOPNOTSUPP.
With this commit, the perf tool then reports:
failed to mmap with 95 (Operation not supported)
which is more clear.
Cc: Pu Hou <bjhoupu@linux.vnet.ibm.com> Cc: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com> Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> --- kernel/events/ring_buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index 2831480..ee97196 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -580,7 +580,7 @@ int rb_alloc_aux(struct ring_buffer *rb, struct perf_event *event, int ret = -ENOMEM, max_order = 0; if (!has_aux(event)) - return -ENOTSUPP; + return -EOPNOTSUPP; if (event->pmu->capabilities & PERF_PMU_CAP_AUX_NO_SG) { /* -- 1.8.3.1
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