From d06b8e7c97c3290e61006e30b32beb9e715fab82 Mon Sep 17 00:00:00 2001 From: Aaron Tomlin Date: Tue, 24 Mar 2026 20:11:58 -0400 Subject: [PATCH] fs/resctrl: Report invalid domain ID when parsing io_alloc_cbm The last_cmd_status file is intended to report details about the most recent resctrl filesystem operation, specifically to aid in diagnosing failures. However, when parsing io_alloc_cbm, if a user provides a domain ID that does not exist in the resource, the operation fails with -EINVAL without updating last_cmd_status. This results in inconsistent behaviour where the system call returns an error, but last_cmd_status misleadingly reports "ok", leaving the user unaware that the failure was caused by an invalid domain ID. Write an error message to last_cmd_status when the target domain ID cannot be found. Fixes: 28fa2cce7a83 ("fs/resctrl: Introduce interface to modify io_alloc capacity bitmasks") Suggested-by: Reinette Chatre Signed-off-by: Aaron Tomlin Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Reviewed-by: Babu Moger Tested-by: Babu Moger Link: https://patch.msgid.link/20260325001159.447075-2-atomlin@atomlin.com --- fs/resctrl/ctrlmondata.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c index cc4237c57cbe..2ef53161ce11 100644 --- a/fs/resctrl/ctrlmondata.c +++ b/fs/resctrl/ctrlmondata.c @@ -992,6 +992,7 @@ static int resctrl_io_alloc_parse_line(char *line, struct rdt_resource *r, } } + rdt_last_cmd_printf("Invalid domain %lu\n", dom_id); return -EINVAL; }