Hi Pingfan,
On Tue, 19 Aug 2025 09:24:22 +0800 Pingfan Liu <[email protected]> wrote: > This patch does two things: > First, register as a listener on bpf_copy_to_kernel() > Second, in order that the hooked bpf-prog can call the sleepable kfuncs, > bpf_handle_pefile and bpf_post_handle_pefile are marked as > KF_SLEEPABLE. > > Signed-off-by: Pingfan Liu <[email protected]> > Cc: Alexei Starovoitov <[email protected]> > Cc: Philipp Rudo <[email protected]> > Cc: Baoquan He <[email protected]> > Cc: Dave Young <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: [email protected] > To: [email protected] > --- > kernel/kexec_pe_image.c | 67 +++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 67 insertions(+) > > diff --git a/kernel/kexec_pe_image.c b/kernel/kexec_pe_image.c > index b0cf9942e68d2..f8debcde6b516 100644 > --- a/kernel/kexec_pe_image.c > +++ b/kernel/kexec_pe_image.c > @@ -38,6 +38,51 @@ static struct kexec_res parsed_resource[3] = { > { KEXEC_RES_CMDLINE_NAME, }, > }; > > +/* > + * @name should be one of : kernel, initrd, cmdline > + */ > +static int bpf_kexec_carrier(const char *name, struct mem_range_result *r) > +{ > + struct kexec_res *res; > + int i; > + > + if (!r || !name) > + return -EINVAL; > + > + for (i = 0; i < 3; i++) { > + if (!strcmp(parsed_resource[i].name, name)) > + break; > + } > + if (i >= 3) > + return -EINVAL; Can you please replace the magic '3' by ARRAY_SIZE, just like you did below when (un-)registering the listener. Thanks Philipp > + > + res = &parsed_resource[i]; > + /* > + * Replace the intermediate resource generated by the previous step. > + */ > + if (!!res->r) > + mem_range_result_put(res->r); > + mem_range_result_get(r); > + res->r = r; > + return 0; > +} > + > +static struct carrier_listener kexec_res_listener[3] = { > + { .name = KEXEC_RES_KERNEL_NAME, > + .alloc_type = 1, > + .handler = bpf_kexec_carrier, > + }, > + { .name = KEXEC_RES_INITRD_NAME, > + .alloc_type = 1, > + .handler = bpf_kexec_carrier, > + }, > + { .name = KEXEC_RES_CMDLINE_NAME, > + /* kmalloc-ed */ > + .alloc_type = 0, > + .handler = bpf_kexec_carrier, > + }, > +}; > + > static bool pe_has_bpf_section(const char *file_buf, unsigned long pe_sz); > > static bool is_valid_pe(const char *kernel_buf, unsigned long kernel_len) > @@ -159,6 +204,22 @@ __attribute__((used, optimize("O0"))) void > bpf_post_handle_pefile(struct kexec_c > dummy += 2; > } > > +BTF_KFUNCS_START(kexec_modify_return_ids) > +BTF_ID_FLAGS(func, bpf_handle_pefile, KF_SLEEPABLE) > +BTF_ID_FLAGS(func, bpf_post_handle_pefile, KF_SLEEPABLE) > +BTF_KFUNCS_END(kexec_modify_return_ids) > + > +static const struct btf_kfunc_id_set kexec_modify_return_set = { > + .owner = THIS_MODULE, > + .set = &kexec_modify_return_ids, > +}; > + > +static int __init kexec_bpf_prog_run_init(void) > +{ > + return register_btf_fmodret_id_set(&kexec_modify_return_set); > +} > +late_initcall(kexec_bpf_prog_run_init); > + > /* > * PE file may be nested and should be unfold one by one. > * Query 'kernel', 'initrd', 'cmdline' in cur_phase, as they are inputs for > the > @@ -213,6 +274,9 @@ static void *pe_image_load(struct kimage *image, > cmdline_start = cmdline; > cmdline_sz = cmdline_len; > > + for (int i = 0; i < ARRAY_SIZE(kexec_res_listener); i++) > + register_carrier_listener(&kexec_res_listener[i]); > + > while (is_valid_format(linux_start, linux_sz) && > pe_has_bpf_section(linux_start, linux_sz)) { > struct kexec_context context; > @@ -250,6 +314,9 @@ static void *pe_image_load(struct kimage *image, > disarm_bpf_prog(); > } > > + for (int i = 0; i < ARRAY_SIZE(kexec_res_listener); i++) > + unregister_carrier_listener(kexec_res_listener[i].name); > + > /* > * image's kernel_buf, initrd_buf, cmdline_buf are set. Now they should > * be updated to the new content.
