[PATCH 4.9 092/310] perf/core: Fix error handling in perf_event_alloc()

From: Greg Kroah-Hartman
Date: Wed Apr 11 2018 - 15:59:57 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>


[ Upstream commit 36cc2b9222b5106de34085c4dd8635ac67ef5cba ]

We don't set an error code here which means that perf_event_alloc()
returns ERR_PTR(0) (in other words NULL). The callers are not expecting
that and would Oops.

Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Fixes: 375637bc5249 ("perf/core: Introduce address range filtering")
Link: http://lkml.kernel.org/r/20170522090418.hvs6icgpdo53wkn5@mwanda
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/events/core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9289,8 +9289,10 @@ perf_event_alloc(struct perf_event_attr
event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
sizeof(unsigned long),
GFP_KERNEL);
- if (!event->addr_filters_offs)
+ if (!event->addr_filters_offs) {
+ err = -ENOMEM;
goto err_per_task;
+ }

/* force hw sync on the address filters */
event->addr_filters_gen = 1;