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| author | Kajol Jain <kjain@linux.ibm.com> | 2020-08-27 12:17:32 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-10-14 10:31:26 +0200 |
| commit | 80e745b6729ed41248442a687943cc7a48e5e66a (patch) | |
| tree | 58da52d7a1ee3148d512a65f515be75681e1501c | |
| parent | 4b00aa56d0e762c51c2b119bf8c6eb76c9fb3de1 (diff) | |
| download | linux-stable-80e745b6729ed41248442a687943cc7a48e5e66a.tar.gz linux-stable-80e745b6729ed41248442a687943cc7a48e5e66a.tar.bz2 linux-stable-80e745b6729ed41248442a687943cc7a48e5e66a.zip | |
perf: Fix task_function_call() error handling
[ Upstream commit 6d6b8b9f4fceab7266ca03d194f60ec72bd4b654 ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | kernel/events/core.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index a17e6302ded5..a35d742b0ba8 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -98,7 +98,7 @@ 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) @@ -114,7 +114,8 @@ 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; |