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Tue, 18 Aug 2026 02:24:32 -0700 (PDT) From: Wandun Chen To: robh@kernel.org, saravanak@kernel.org, rppt@kernel.org, m.szyprowski@samsung.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: akpm@linux-foundation.org Subject: [PATCH v2 1/5] of: reserved_mem: skip init for regions whose early reservation failed Date: Tue, 18 Aug 2026 17:24:16 +0800 Message-ID: <20260818092420.2859026-2-chenwandun1@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260818092420.2859026-1-chenwandun1@gmail.com> References: <20260818092420.2859026-1-chenwandun1@gmail.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Wandun Chen __reserved_mem_reserve_reg() discards the error from early_init_dt_reserve_memory() and returns 0 unconditionally, so the caller counts the node in total_reserved_mem_cnt and the late scan initializes it without checking whether the early reservation actually succeeded. A region whose reservation failed is then handed to a device assuming the memory is protected. Propagate the error so failed reservations are no longer counted, and record the failed nodes so fdt_scan_reserved_mem_late() can skip them. Recording the failed nodes explicitly is necessary because fdt_scan_reserved_mem_late() rescans the DT independently. It cannot tell from memblock whether early reservation succeeded. The failed-node array is bounded by MAX_RESERVED_REGIONS, the number of static regions is not bounded by it, so on overflow the extra nodes fall back to being initialized, which is the current behavior. Fixes: 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory regions are processed") Signed-off-by: Wandun Chen --- drivers/of/of_reserved_mem.c | 65 ++++++++++++++++++++++++++++++------ 1 file changed, 54 insertions(+), 11 deletions(-) diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c index 8c9d6395d6a3..c6e73d710ee1 100644 --- a/drivers/of/of_reserved_mem.c +++ b/drivers/of/of_reserved_mem.c @@ -32,6 +32,30 @@ static struct reserved_mem *reserved_mem __refdata = reserved_mem_array; static int total_reserved_mem_cnt = MAX_RESERVED_REGIONS; static int reserved_mem_count; +static int reserve_failed_nodes[MAX_RESERVED_REGIONS] __initdata; +static int reserve_failed_nodes_cnt __initdata; + +static bool __init reserved_mem_node_reserve_failed(int node) +{ + int i; + + for (i = 0; i < reserve_failed_nodes_cnt; i++) + if (reserve_failed_nodes[i] == node) + return true; + return false; +} + +static bool __init record_reserve_failed_node(int node, const char *uname) +{ + if (reserve_failed_nodes_cnt == MAX_RESERVED_REGIONS) { + pr_err("too many failed regions, '%s' reservation failed\n", uname); + return false; + } + + reserve_failed_nodes[reserve_failed_nodes_cnt++] = node; + return true; +} + static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size, phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap, phys_addr_t *res_base) @@ -141,7 +165,8 @@ static int __init early_init_dt_reserve_memory(phys_addr_t base, * first entry in 'reg' property */ static int __init __reserved_mem_reserve_reg(unsigned long node, - const char *uname) + const char *uname, + bool *should_record_failed_node) { phys_addr_t base, size; int len, err; @@ -149,6 +174,8 @@ static int __init __reserved_mem_reserve_reg(unsigned long node, bool nomap; u64 b, s; + *should_record_failed_node = false; + prop = of_flat_dt_get_addr_size_prop(node, "reg", &len); if (!prop || !len) return -ENOENT; @@ -167,14 +194,20 @@ static int __init __reserved_mem_reserve_reg(unsigned long node, base = b; size = s; - if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) { - fdt_fixup_reserved_mem_node(node, base, size); - pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n", - uname, &base, (unsigned long)(size / SZ_1M)); - } else { + if (!size) + return -EINVAL; + + err = early_init_dt_reserve_memory(base, size, nomap); + if (err) { + *should_record_failed_node = true; pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n", uname, &base, (unsigned long)(size / SZ_1M)); + return err; } + + fdt_fixup_reserved_mem_node(node, base, size); + pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n", + uname, &base, (unsigned long)(size / SZ_1M)); return 0; } @@ -306,10 +339,14 @@ void __init fdt_scan_reserved_mem_late(void) base = b; size = s; - if (size) { - uname = fdt_get_name(fdt, child, NULL); - fdt_init_reserved_mem_node(child, uname, base, size); - } + if (!size) + continue; + + if (reserved_mem_node_reserve_failed(child)) + continue; + + uname = fdt_get_name(fdt, child, NULL); + fdt_init_reserved_mem_node(child, uname, base, size); } /* check for overlapping reserved regions */ @@ -349,6 +386,7 @@ int __init fdt_scan_reserved_mem(void) fdt_for_each_subnode(child, fdt, node) { const char *uname; + bool should_record_failed_node; int err; if (!of_fdt_device_is_available(fdt, child)) @@ -356,9 +394,14 @@ int __init fdt_scan_reserved_mem(void) uname = fdt_get_name(fdt, child, NULL); - err = __reserved_mem_reserve_reg(child, uname); + err = __reserved_mem_reserve_reg(child, uname, + &should_record_failed_node); if (!err) count++; + else if (should_record_failed_node && + !record_reserve_failed_node(child, uname)) + /* Keep a slot for the untracked node's late initialization. */ + count++; /* * Save the nodes for the dynamically-placed regions -- 2.43.0