In reserve_module_tags(), the tag overflow check is gated on mem_alloc_profiling_enabled(): if (mem_alloc_profiling_enabled() && !tags_addressable()) If profiling is toggled off at runtime and a module is loaded whose tags exceed the compressed-mode limit, shutdown_mem_profiling() is skipped. vm_module_tags_populate() still maps memory for the tags and the module loads successfully, but the total tag count now exceeds what NR_UNUSED_PAGEFLAG_BITS can address. Once profiling is re-enabled, ref_to_idx() computes each tag's index as its position in the alloc_tag array. update_page_tag_ref() masks it to alloc_tag_ref_mask before storing in page->flags. Indices beyond the mask are truncated and idx_to_ref() resolves them to wrong tags. This silently corrupts /proc/allocinfo: allocated pages get attributed to the wrong call sites, so the statistics it reports are wrong. mem_alloc_profiling_enabled() and mem_profiling_compressed are independent. Once compressed mode is established at boot, it stays active regardless of runtime toggles of mem_profiling. Remove the mem_alloc_profiling_enabled() guard. On overflow, shut down profiling, release the reservation, and return -EAGAIN so that layout_and_allocate() retries with profiling disabled: codetag sections are then placed as regular module data and the module loads without profiling rather than being rejected entirely. Fixes: 4835f747d3ed ("alloc_tag: support for page allocation tag compression") Cc: stable@vger.kernel.org Suggested-by: Suren Baghdasaryan Signed-off-by: Hao Ge --- kernel/module/main.c | 25 +++++++++++++++++++++++-- mm/alloc_tag.c | 8 +++++--- 2 files changed, 28 insertions(+), 5 deletions(-) diff --git a/kernel/module/main.c b/kernel/module/main.c index 46dd8d25a605..ed26f167be84 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -2944,6 +2944,7 @@ static struct module *layout_and_allocate(struct load_info *info, int flags) { struct module *mod; int err; + unsigned long frob_size[MOD_MEM_NUM_TYPES]; /* Allow arches to frob section contents and sizes. */ err = module_frob_arch_sections(info->hdr, info->sechdrs, @@ -2966,18 +2967,38 @@ static struct module *layout_and_allocate(struct load_info *info, int flags) */ module_mark_ro_after_init(info->hdr, info->sechdrs, info->secstrings); + /* + * Save the sizes reserved by module_frob_arch_sections() so they can + * be restored if we retry below. + */ + for_each_mod_mem_type(type) + frob_size[type] = info->mod->mem[type].size; + /* * Determine total sizes, and put offsets in sh_entsize. For now * this is done generically; there doesn't appear to be any * special cases for the architectures. */ +retry: layout_sections(info->mod, info); layout_symtab(info->mod, info); /* Allocate and move to the final place */ err = move_module(info->mod, info); - if (err) - return ERR_PTR(err); + if (err) { + if (err != -EAGAIN) + return ERR_PTR(err); + /* + * -EAGAIN means profiling was disabled but the module + * can still load without it. Reset state and retry. + */ + rewrite_section_headers(info, flags); + for_each_mod_mem_type(type) + info->mod->mem[type].size = frob_size[type]; + info->sechdrs[info->index.sym].sh_flags &= ~(unsigned long)SHF_ALLOC; + info->sechdrs[info->index.str].sh_flags &= ~(unsigned long)SHF_ALLOC; + goto retry; + } /* Module has been copied to its final place now: return it. */ mod = (void *)info->sechdrs[info->index.mod].sh_addr; diff --git a/mm/alloc_tag.c b/mm/alloc_tag.c index af44f90379f2..0a7b657fe2de 100644 --- a/mm/alloc_tag.c +++ b/mm/alloc_tag.c @@ -950,10 +950,12 @@ static void *reserve_module_tags(struct module *mod, unsigned long size, int grow_res; module_tags.size = offset + size; - if (mem_alloc_profiling_enabled() && !tags_addressable()) { + if (!tags_addressable()) { shutdown_mem_profiling(true); - pr_warn("With module %s there are too many tags to fit in %d page flag bits. Memory allocation profiling is disabled!\n", - mod->name, NR_UNUSED_PAGEFLAG_BITS); + pr_warn_once("With module %s there are too many tags to fit in %d page flag bits. Memory allocation profiling is disabled!\n", + mod->name, NR_UNUSED_PAGEFLAG_BITS); + release_module_tags(mod, false); + return ERR_PTR(-EAGAIN); } grow_res = vm_module_tags_populate(); -- 2.25.1