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authorKajol Jain <kjain@linux.ibm.com>2020-08-27 12:17:32 +0530
committerIngo Molnar <mingo@kernel.org>2020-10-09 08:18:33 +0200
commit6d6b8b9f4fceab7266ca03d194f60ec72bd4b654 (patch)
tree0b4ccabc93fef10e8c6f2929907527060549d49a
parentc85fb28b6f999db9928b841f63f1beeb3074eeca (diff)
downloadlinux-stericsson-6d6b8b9f4fceab7266ca03d194f60ec72bd4b654.tar.gz
perf: Fix task_function_call() error handling
The error handling introduced by commit: 2ed6edd33a21 ("perf: Add cond_resched() to task_function_call()") looses any return value from smp_call_function_single() that is not {0, -EINVAL}. This is a problem because it will return -EXNIO when the target CPU is offline. Worse, in that case it'll turn into an infinite loop. Fixes: 2ed6edd33a21 ("perf: Add cond_resched() to task_function_call()") Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Kajol Jain <kjain@linux.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Barret Rhoden <brho@google.com> Tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Link: https://lkml.kernel.org/r/20200827064732.20860-1-kjain@linux.ibm.com
-rw-r--r--kernel/events/core.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 7ed5248f0445..e8bf92202542 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -99,7 +99,7 @@ static void remote_function(void *data)
* retry due to any failures in smp_call_function_single(), such as if the
* task_cpu() goes offline concurrently.
*
- * returns @func return value or -ESRCH when the process isn't running
+ * returns @func return value or -ESRCH or -ENXIO when the process isn't running
*/
static int
task_function_call(struct task_struct *p, remote_function_f func, void *info)
@@ -115,7 +115,8 @@ task_function_call(struct task_struct *p, remote_function_f func, void *info)
for (;;) {
ret = smp_call_function_single(task_cpu(p), remote_function,
&data, 1);
- ret = !ret ? data.ret : -EAGAIN;
+ if (!ret)
+ ret = data.ret;
if (ret != -EAGAIN)
break;