Re: [PATCH] Revert "tracing/trigger: Fix to return error if failed to alloc snapshot"

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, Apr 18, 2024 at 06:58:06PM +0530, Siddh Raman Pant wrote:
> This reverts commit b5085b5ac1d96ea2a8a6240f869655176ce44197.
> 
> The change has an incorrect assumption about the return value because
> in the current stable trees for versions 5.15 and before, the following
> commit responsible for making 0 a success value is not present:
> b8cc44a4d3c1 ("tracing: Remove logic for registering multiple event triggers at a time")
> 
> The return value should be 0 on failure in the current tree, because in
> the functions event_trigger_callback() and event_enable_trigger_func(),
> we have:
> 
> 	ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
> 	/*
> 	 * The above returns on success the # of functions enabled,
> 	 * but if it didn't find any functions it returns zero.
> 	 * Consider no functions a failure too.
> 	 */
> 	if (!ret) {
> 		ret = -ENOENT;
> 
> Cc: stable@kernel.org # 5.15, 5.10, 5.4, 4.19
> Signed-off-by: Siddh Raman Pant <siddh.raman.pant@oracle.com>
> ---
>  kernel/trace/trace_events_trigger.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)

Now queued up everywhere, thanks.

greg k-h