[PATCH 6.1 23/96] bpf: fix order of args in call to bpf_map_kvcalloc

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6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mohammad Shehar Yaar Tausif <sheharyaar48@xxxxxxxxx>

[ Upstream commit af253aef183a31ce62d2e39fc520b0ebfb562bb9 ]

The original function call passed size of smap->bucket before the number of
buckets which raises the error 'calloc-transposed-args' on compilation.

Vlastimil Babka added:

The order of parameters can be traced back all the way to 6ac99e8f23d4
("bpf: Introduce bpf sk local storage") accross several refactorings,
and that's why the commit is used as a Fixes: tag.

In v6.10-rc1, a different commit 2c321f3f70bc ("mm: change inlined
allocation helpers to account at the call site") however exposed the
order of args in a way that gcc-14 has enough visibility to start
warning about it, because (in !CONFIG_MEMCG case) bpf_map_kvcalloc is
then a macro alias for kvcalloc instead of a static inline wrapper.

To sum up the warning happens when the following conditions are all met:

- gcc-14 is used (didn't see it with gcc-13)
- commit 2c321f3f70bc is present
- CONFIG_MEMCG is not enabled in .config
- CONFIG_WERROR turns this from a compiler warning to error

Fixes: 6ac99e8f23d4 ("bpf: Introduce bpf sk local storage")
Reviewed-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Tested-by: Christian Kujau <lists@xxxxxxxxxxxxxxx>
Signed-off-by: Mohammad Shehar Yaar Tausif <sheharyaar48@xxxxxxxxx>
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Link: https://lore.kernel.org/r/20240710100521.15061-2-vbabka@xxxxxxx
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 kernel/bpf/bpf_local_storage.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index 888b8e481083f..51a9f024c1829 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -620,8 +620,8 @@ bpf_local_storage_map_alloc(union bpf_attr *attr,
 	nbuckets = max_t(u32, 2, nbuckets);
 	smap->bucket_log = ilog2(nbuckets);
 
-	smap->buckets = bpf_map_kvcalloc(&smap->map, sizeof(*smap->buckets),
-					 nbuckets, GFP_USER | __GFP_NOWARN);
+	smap->buckets = bpf_map_kvcalloc(&smap->map, nbuckets,
+					 sizeof(*smap->buckets), GFP_USER | __GFP_NOWARN);
 	if (!smap->buckets) {
 		bpf_map_area_free(smap);
 		return ERR_PTR(-ENOMEM);
-- 
2.43.0







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