From: Li Huafei lihuafei1@huawei.com
commit 96df59b1ae23f5c11698c3c2159aeb2ecd4944a4 upstream.
This is reported by kmemleak detector:
unreferenced object 0xff60000082864000 (size 9588): comm "kexec", pid 146, jiffies 4294900634 (age 64.788s) hex dump (first 32 bytes): d0 0d fe ed 00 00 12 ed 00 00 00 48 00 00 11 40 ...........H...@ 00 00 00 28 00 00 00 11 00 00 00 02 00 00 00 00 ...(............ backtrace: [<00000000f95b17c4>] kmemleak_alloc+0x34/0x3e [<00000000b9ec8e3e>] kmalloc_order+0x9c/0xc4 [<00000000a95cf02e>] kmalloc_order_trace+0x34/0xb6 [<00000000f01e68b4>] __kmalloc+0x5c2/0x62a [<000000002bd497b2>] kvmalloc_node+0x66/0xd6 [<00000000906542fa>] of_kexec_alloc_and_setup_fdt+0xa6/0x6ea [<00000000e1166bde>] elf_kexec_load+0x206/0x4ec [<0000000036548e09>] kexec_image_load_default+0x40/0x4c [<0000000079fbe1b4>] sys_kexec_file_load+0x1c4/0x322 [<0000000040c62c03>] ret_from_syscall+0x0/0x2
In elf_kexec_load(), a buffer is allocated via kvmalloc() to store fdt. While it's not freed back to system when kexec kernel is reloaded or unloaded. Then memory leak is caused. Fix it by introducing riscv specific function arch_kimage_file_post_load_cleanup(), and freeing the buffer there.
Fixes: 6261586e0c91 ("RISC-V: Add kexec_file support") Signed-off-by: Li Huafei lihuafei1@huawei.com Reviewed-by: Conor Dooley conor.dooley@microchip.com Reviewed-by: Liao Chang liaochang1@huawei.com Link: https://lore.kernel.org/r/20221104095658.141222-1-lihuafei1@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/riscv/include/asm/kexec.h | 5 +++++ arch/riscv/kernel/elf_kexec.c | 10 ++++++++++ 2 files changed, 15 insertions(+)
--- a/arch/riscv/include/asm/kexec.h +++ b/arch/riscv/include/asm/kexec.h @@ -39,6 +39,7 @@ crash_setup_regs(struct pt_regs *newregs #define ARCH_HAS_KIMAGE_ARCH
struct kimage_arch { + void *fdt; /* For CONFIG_KEXEC_FILE */ unsigned long fdt_addr; };
@@ -62,6 +63,10 @@ int arch_kexec_apply_relocations_add(str const Elf_Shdr *relsec, const Elf_Shdr *symtab); #define arch_kexec_apply_relocations_add arch_kexec_apply_relocations_add + +struct kimage; +int arch_kimage_file_post_load_cleanup(struct kimage *image); +#define arch_kimage_file_post_load_cleanup arch_kimage_file_post_load_cleanup #endif
#endif --- a/arch/riscv/kernel/elf_kexec.c +++ b/arch/riscv/kernel/elf_kexec.c @@ -21,6 +21,14 @@ #include <linux/memblock.h> #include <asm/setup.h>
+int arch_kimage_file_post_load_cleanup(struct kimage *image) +{ + kvfree(image->arch.fdt); + image->arch.fdt = NULL; + + return kexec_image_post_load_cleanup_default(image); +} + static int riscv_kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, struct kexec_elf_info *elf_info, unsigned long old_pbase, unsigned long new_pbase) @@ -298,6 +306,8 @@ static void *elf_kexec_load(struct kimag pr_err("Error add DTB kbuf ret=%d\n", ret); goto out_free_fdt; } + /* Cache the fdt buffer address for memory cleanup */ + image->arch.fdt = fdt; pr_notice("Loaded device tree at 0x%lx\n", kbuf.mem); goto out;