Re: [Intel-wired-lan] [PATCH v3] net: ethernet: fix uninitialized pointers with free attribute
From: Dan Carpenter <hidden>
Date: 2025-11-17 13:11:39
Also in:
intel-wired-lan, linux-hyperv, lkml
On Thu, Nov 06, 2025 at 03:07:26PM +0100, Alexander Lobakin wrote:
quoted
diff --git a/drivers/net/ethernet/intel/ice/ice_flow.c b/drivers/net/ethernet/intel/ice/ice_flow.c index 6d5c939dc8a515c252cd2b77d155b69fa264ee92..3590dacf3ee57879b3809d715e40bb290e40c4aa 100644 --- a/drivers/net/ethernet/intel/ice/ice_flow.c +++ b/drivers/net/ethernet/intel/ice/ice_flow.c@@ -1573,12 +1573,13 @@ ice_flow_set_parser_prof(struct ice_hw *hw, u16 dest_vsi, u16 fdir_vsi, struct ice_parser_profile *prof, enum ice_block blk) { u64 id = find_first_bit(prof->ptypes, ICE_FLOW_PTYPE_MAX); - struct ice_flow_prof_params *params __free(kfree); u8 fv_words = hw->blk[blk].es.fvw; int status; int i, idx; - params = kzalloc(sizeof(*params), GFP_KERNEL); + struct ice_flow_prof_params *params __free(kfree) = + kzalloc(sizeof(*params), GFP_KERNEL);Please don't do it that way. It's not C++ with RAII and declare-where-you-use. Just leave the variable declarations where they are, but initialize them with `= NULL`. Variable declarations must be in one block and sorted from the longest to the shortest.
These days, with __free the trend is to say yes this is RAII and we should declare it where you use it. I personally don't have a strong opinion on this either way, but other maintainers do and will NAK the `= NULL` approach. The documentation says you should do it that way and avoid the `= NULL` as well. The issue is with lock ordering. It's a FILO ordering, so if we require a specific unlock order then declaring variables at the top could mess things up. The counter argument is that if you declare a variable after a goto then that's undefined behavior as well. Clang will detect that bug so it be detected before it hits actual users. regards, dan carpenter