Date:   Tue, 24 Jan 2023 15:02:54 -0800
Mime-Version: 1.0
Message-ID: <20230124230254.295589-1-isaacmanjarres@google.com>
Subject: [PATCH v1] Revert "mm: kmemleak: alloc gray object for reserved
 region with direct map"
From:   "Isaac J. Manjarres" <isaacmanjarres@google.com>
To:     Catalin Marinas <catalin.marinas@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>
Cc:     linux-mm@kvack.org, Saravana Kannan <saravanak@google.com>,
        "Isaac J. Manjarres" <isaacmanjarres@google.com>,
        stable@vger.kernel.org, Calvin Zhang <calvinzhang.cool@gmail.com>,
        kernel-team@android.com, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

This reverts commit 972fa3a7c17c9d60212e32ecc0205dc585b1e769.

Kmemleak operates by periodically scanning memory regions for pointers
to allocated memory blocks to determine if they are leaked or not.
However, reserved memory regions can be used for DMA transactions
between a device and a CPU, and thus, wouldn't contain pointers to
allocated memory blocks, making them inappropriate for kmemleak to
scan. Thus, revert this commit.

Cc: stable@vger.kernel.org # 5.17+
Cc: Calvin Zhang <calvinzhang.cool@gmail.com>
Signed-off-by: Isaac J. Manjarres <isaacmanjarres@google.com>
---
 drivers/of/fdt.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index f08b25195ae7..d1a68b6d03b3 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -26,7 +26,6 @@
 #include <linux/serial_core.h>
 #include <linux/sysfs.h>
 #include <linux/random.h>
-#include <linux/kmemleak.h>
 
 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
 #include <asm/page.h>
@@ -525,12 +524,9 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
 		size = dt_mem_next_cell(dt_root_size_cells, &prop);
 
 		if (size &&
-		    early_init_dt_reserve_memory(base, size, nomap) == 0) {
+		    early_init_dt_reserve_memory(base, size, nomap) == 0)
 			pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
 				uname, &base, (unsigned long)(size / SZ_1M));
-			if (!nomap)
-				kmemleak_alloc_phys(base, size, 0);
-		}
 		else
 			pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
 			       uname, &base, (unsigned long)(size / SZ_1M));
-- 
2.39.1.405.gd4c25cc71f-goog