From 768c33be1b3166791bd554abd105154719eba43d Mon Sep 17 00:00:00 2001
From: Suren Baghdasaryan <surenb@google.com>
Date: Thu, 21 Mar 2024 09:36:29 -0700
Subject: mm: introduce __GFP_NO_OBJ_EXT flag to selectively prevent
 slabobj_ext creation
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Introduce __GFP_NO_OBJ_EXT flag in order to prevent recursive allocations
when allocating slabobj_ext on a slab.

Link: https://lkml.kernel.org/r/20240321163705.3067592-8-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andreas Hindborg <a.hindborg@samsung.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: "Björn Roy Baron" <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Gary Guo <gary@garyguo.net>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/slub.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'mm')

diff --git a/mm/slub.c b/mm/slub.c
index 5c896c76812d..2cb53642a091 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1889,6 +1889,8 @@ static int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
 	void *vec;
 
 	gfp &= ~OBJCGS_CLEAR_MASK;
+	/* Prevent recursive extension vector allocation */
+	gfp |= __GFP_NO_OBJ_EXT;
 	vec = kcalloc_node(objects, sizeof(struct slabobj_ext), gfp,
 			   slab_nid(slab));
 	if (!vec)
-- 
cgit