Hi Baoquan,
On Fri, 29 Oct 2021 17:26:35 +0800
Baoquan He <bhe@xxxxxxxxxx> wrote:
> A memory leak is reported by kmemleak scanning:
>
> unreferenced object 0x38000195000 (size 4096):
> comm "kexec", pid 8548, jiffies 4294953647 (age 32443.270s)
> hex dump (first 32 bytes):
> 00 00 00 c8 20 00 00 00 00 00 00 c0 02 80 00 00 .... ...........
> 40 40 40 40 40 40 40 40 00 00 00 00 00 00 00 00 @@@@@@@@........
> backtrace:
> [<0000000011a2f199>] __vmalloc_node_range+0xc0/0x140
> [<0000000081fa2752>] vzalloc+0x5a/0x70
> [<0000000063a4c92d>] ipl_report_finish+0x2c/0x180
> [<00000000553304da>] kexec_file_add_ipl_report+0xf4/0x150
> [<00000000862d033f>] kexec_file_add_components+0x124/0x160
> [<000000000d2717bb>] arch_kexec_kernel_image_load+0x62/0x90
> [<000000002e0373b6>] kimage_file_alloc_init+0x1aa/0x2e0
> [<0000000060f2d14f>] __do_sys_kexec_file_load+0x17c/0x2c0
> [<000000008c86fe5a>] __s390x_sys_kexec_file_load+0x40/0x50
> [<000000001fdb9dac>] __do_syscall+0x1bc/0x1f0
> [<000000003ee4258d>] system_call+0x78/0xa0
>
> The ipl report buffer is allocated via vmalloc, while has no chance to free
> if the kexe loading is unloaded. This will cause obvious memory leak
> when kexec/kdump kernel is reloaded, manually, or triggered, e.g by
> memory hotplug.
>
> Here, add struct kimage_arch to s390 to pass out the ipl report buffer
> address, and introduce arch dependent function
> arch_kimage_file_post_load_cleanup() to free it when unloaded.
>
> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
other than a missing
Fixes: 99feaa717e55 ("s390/kexec_file: Create ipl report and pass to
next kernel")
the patch looks good to me.
Reviewed-by: Philipp Rudo <prudo@xxxxxxxxxx>
> ---
> arch/s390/include/asm/kexec.h | 7 +++++++
> arch/s390/kernel/machine_kexec_file.c | 9 +++++++++
> 2 files changed, 16 insertions(+)
>
> diff --git a/arch/s390/include/asm/kexec.h b/arch/s390/include/asm/kexec.h
> index ea398a05f643..9f16e99fb882 100644
> --- a/arch/s390/include/asm/kexec.h
> +++ b/arch/s390/include/asm/kexec.h
> @@ -74,6 +74,13 @@ void *kexec_file_add_components(struct kimage *image,
> int arch_kexec_do_relocs(int r_type, void *loc, unsigned long val,
> unsigned long addr);
>
> +#define ARCH_HAS_KIMAGE_ARCH
> +
> +struct kimage_arch {
> + void *ipl_buf;
> +};
> +
> +
> extern const struct kexec_file_ops s390_kexec_image_ops;
> extern const struct kexec_file_ops s390_kexec_elf_ops;
>
> diff --git a/arch/s390/kernel/machine_kexec_file.c b/arch/s390/kernel/machine_kexec_file.c
> index f9e4baa64b67..584c48b631b2 100644
> --- a/arch/s390/kernel/machine_kexec_file.c
> +++ b/arch/s390/kernel/machine_kexec_file.c
> @@ -202,6 +202,7 @@ static int kexec_file_add_ipl_report(struct kimage *image,
> buf.buffer = ipl_report_finish(data->report);
> buf.bufsz = data->report->size;
> buf.memsz = buf.bufsz;
> + image->arch.ipl_buf = buf.buffer;
>
> data->memsz += buf.memsz;
>
> @@ -321,3 +322,11 @@ int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
>
> return kexec_image_probe_default(image, buf, buf_len);
> }
> +
> +int arch_kimage_file_post_load_cleanup(struct kimage *image)
> +{
> + kvfree(image->arch.ipl_buf);
> + image->arch.ipl_buf = NULL;
> +
> + return kexec_image_post_load_cleanup_default(image);
> +}
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