Merge tag 'modules-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

Pull module updates from Luis Chamberlain:
 "The summary of the changes for this pull requests is:

   - Song Liu's new struct module_memory replacement

   - Nick Alcock's MODULE_LICENSE() removal for non-modules

   - My cleanups and enhancements to reduce the areas where we vmalloc
     module memory for duplicates, and the respective debug code which
     proves the remaining vmalloc pressure comes from userspace.

  Most of the changes have been in linux-next for quite some time except
  the minor fixes I made to check if a module was already loaded prior
  to allocating the final module memory with vmalloc and the respective
  debug code it introduces to help clarify the issue. Although the
  functional change is small it is rather safe as it can only *help*
  reduce vmalloc space for duplicates and is confirmed to fix a bootup
  issue with over 400 CPUs with KASAN enabled. I don't expect stable
  kernels to pick up that fix as the cleanups would have also had to
  have been picked up. Folks on larger CPU systems with modules will
  want to just upgrade if vmalloc space has been an issue on bootup.

  Given the size of this request, here's some more elaborate details:

  The functional change change in this pull request is the very first
  patch from Song Liu which replaces the 'struct module_layout' with a
  new 'struct module_memory'. The old data structure tried to put
  together all types of supported module memory types in one data
  structure, the new one abstracts the differences in memory types in a
  module to allow each one to provide their own set of details. This
  paves the way in the future so we can deal with them in a cleaner way.
  If you look at changes they also provide a nice cleanup of how we
  handle these different memory areas in a module. This change has been
  in linux-next since before the merge window opened for v6.3 so to
  provide more than a full kernel cycle of testing. It's a good thing as
  quite a bit of fixes have been found for it.

  Jason Baron then made dynamic debug a first class citizen module user
  by using module notifier callbacks to allocate / remove module
  specific dynamic debug information.

  Nick Alcock has done quite a bit of work cross-tree to remove module
  license tags from things which cannot possibly be module at my request
  so to:

   a) help him with his longer term tooling goals which require a
      deterministic evaluation if a piece a symbol code could ever be
      part of a module or not. But quite recently it is has been made
      clear that tooling is not the only one that would benefit.
      Disambiguating symbols also helps efforts such as live patching,
      kprobes and BPF, but for other reasons and R&D on this area is
      active with no clear solution in sight.

   b) help us inch closer to the now generally accepted long term goal
      of automating all the MODULE_LICENSE() tags from SPDX license tags

  In so far as a) is concerned, although module license tags are a no-op
  for non-modules, tools which would want create a mapping of possible
  modules can only rely on the module license tag after the commit
  8b41fc4454e ("kbuild: create modules.builtin without
  Makefile.modbuiltin or tristate.conf").

  Nick has been working on this *for years* and AFAICT I was the only
  one to suggest two alternatives to this approach for tooling. The
  complexity in one of my suggested approaches lies in that we'd need a
  possible-obj-m and a could-be-module which would check if the object
  being built is part of any kconfig build which could ever lead to it
  being part of a module, and if so define a new define
  -DPOSSIBLE_MODULE [0].

  A more obvious yet theoretical approach I've suggested would be to
  have a tristate in kconfig imply the same new -DPOSSIBLE_MODULE as
  well but that means getting kconfig symbol names mapping to modules
  always, and I don't think that's the case today. I am not aware of
  Nick or anyone exploring either of these options. Quite recently Josh
  Poimboeuf has pointed out that live patching, kprobes and BPF would
  benefit from resolving some part of the disambiguation as well but for
  other reasons. The function granularity KASLR (fgkaslr) patches were
  mentioned but Joe Lawrence has clarified this effort has been dropped
  with no clear solution in sight [1].

  In the meantime removing module license tags from code which could
  never be modules is welcomed for both objectives mentioned above. Some
  developers have also welcomed these changes as it has helped clarify
  when a module was never possible and they forgot to clean this up, and
  so you'll see quite a bit of Nick's patches in other pull requests for
  this merge window. I just picked up the stragglers after rc3. LWN has
  good coverage on the motivation behind this work [2] and the typical
  cross-tree issues he ran into along the way. The only concrete blocker
  issue he ran into was that we should not remove the MODULE_LICENSE()
  tags from files which have no SPDX tags yet, even if they can never be
  modules. Nick ended up giving up on his efforts due to having to do
  this vetting and backlash he ran into from folks who really did *not
  understand* the core of the issue nor were providing any alternative /
  guidance. I've gone through his changes and dropped the patches which
  dropped the module license tags where an SPDX license tag was missing,
  it only consisted of 11 drivers. To see if a pull request deals with a
  file which lacks SPDX tags you can just use:

    ./scripts/spdxcheck.py -f \
	$(git diff --name-only commid-id | xargs echo)

  You'll see a core module file in this pull request for the above, but
  that's not related to his changes. WE just need to add the SPDX
  license tag for the kernel/module/kmod.c file in the future but it
  demonstrates the effectiveness of the script.

  Most of Nick's changes were spread out through different trees, and I
  just picked up the slack after rc3 for the last kernel was out. Those
  changes have been in linux-next for over two weeks.

  The cleanups, debug code I added and final fix I added for modules
  were motivated by David Hildenbrand's report of boot failing on a
  systems with over 400 CPUs when KASAN was enabled due to running out
  of virtual memory space. Although the functional change only consists
  of 3 lines in the patch "module: avoid allocation if module is already
  present and ready", proving that this was the best we can do on the
  modules side took quite a bit of effort and new debug code.

  The initial cleanups I did on the modules side of things has been in
  linux-next since around rc3 of the last kernel, the actual final fix
  for and debug code however have only been in linux-next for about a
  week or so but I think it is worth getting that code in for this merge
  window as it does help fix / prove / evaluate the issues reported with
  larger number of CPUs. Userspace is not yet fixed as it is taking a
  bit of time for folks to understand the crux of the issue and find a
  proper resolution. Worst come to worst, I have a kludge-of-concept [3]
  of how to make kernel_read*() calls for modules unique / converge
  them, but I'm currently inclined to just see if userspace can fix this
  instead"

Link: https://lore.kernel.org/all/Y/kXDqW+7d71C4wz@bombadil.infradead.org/ [0]
Link: https://lkml.kernel.org/r/025f2151-ce7c-5630-9b90-98742c97ac65@redhat.com [1]
Link: https://lwn.net/Articles/927569/ [2]
Link: https://lkml.kernel.org/r/20230414052840.1994456-3-mcgrof@kernel.org [3]

* tag 'modules-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (121 commits)
  module: add debugging auto-load duplicate module support
  module: stats: fix invalid_mod_bytes typo
  module: remove use of uninitialized variable len
  module: fix building stats for 32-bit targets
  module: stats: include uapi/linux/module.h
  module: avoid allocation if module is already present and ready
  module: add debug stats to help identify memory pressure
  module: extract patient module check into helper
  modules/kmod: replace implementation with a semaphore
  Change DEFINE_SEMAPHORE() to take a number argument
  module: fix kmemleak annotations for non init ELF sections
  module: Ignore L0 and rename is_arm_mapping_symbol()
  module: Move is_arm_mapping_symbol() to module_symbol.h
  module: Sync code of is_arm_mapping_symbol()
  scripts/gdb: use mem instead of core_layout to get the module address
  interconnect: remove module-related code
  interconnect: remove MODULE_LICENSE in non-modules
  zswap: remove MODULE_LICENSE in non-modules
  zpool: remove MODULE_LICENSE in non-modules
  x86/mm/dump_pagetables: remove MODULE_LICENSE in non-modules
  ...

1 files changed, 115 insertions, 25 deletions

diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index 1c877561a7d2..dc7b0160c480 100644
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -3,6 +3,7 @@
  *
  * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
+ * Copyright (C) 2023 Luis Chamberlain <mcgrof@kernel.org>
  */
 
 #include <linux/elf.h>
@@ -17,27 +18,19 @@
 #define ARCH_SHF_SMALL 0
 #endif
 
-/* If this is set, the section belongs in the init part of the module */
-#define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG - 1))
-/* Maximum number of characters written by module_flags() */
-#define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)
-
-#ifndef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
-#define	data_layout core_layout
-#endif
-
 /*
- * Modules' sections will be aligned on page boundaries
- * to ensure complete separation of code and data, but
- * only when CONFIG_STRICT_MODULE_RWX=y
+ * Use highest 4 bits of sh_entsize to store the mod_mem_type of this
+ * section. This leaves 28 bits for offset on 32-bit systems, which is
+ * about 256 MiB (WARN_ON_ONCE if we exceed that).
  */
-static inline unsigned int strict_align(unsigned int size)
-{
-	if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
-		return PAGE_ALIGN(size);
-	else
-		return size;
-}
+
+#define SH_ENTSIZE_TYPE_BITS	4
+#define SH_ENTSIZE_TYPE_SHIFT	(BITS_PER_LONG - SH_ENTSIZE_TYPE_BITS)
+#define SH_ENTSIZE_TYPE_MASK	((1UL << SH_ENTSIZE_TYPE_BITS) - 1)
+#define SH_ENTSIZE_OFFSET_MASK	((1UL << (BITS_PER_LONG - SH_ENTSIZE_TYPE_BITS)) - 1)
+
+/* Maximum number of characters written by module_flags() */
+#define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)
 
 extern struct mutex module_mutex;
 extern struct list_head modules;
@@ -53,7 +46,6 @@ extern const struct kernel_symbol __stop___ksymtab_gpl[];
 extern const s32 __start___kcrctab[];
 extern const s32 __start___kcrctab_gpl[];
 
-#include <linux/dynamic_debug.h>
 struct load_info {
 	const char *name;
 	/* pointer to module in temporary copy, freed at end of load_module() */
@@ -63,12 +55,14 @@ struct load_info {
 	Elf_Shdr *sechdrs;
 	char *secstrings, *strtab;
 	unsigned long symoffs, stroffs, init_typeoffs, core_typeoffs;
-	struct _ddebug_info dyndbg;
 	bool sig_ok;
 #ifdef CONFIG_KALLSYMS
 	unsigned long mod_kallsyms_init_off;
 #endif
 #ifdef CONFIG_MODULE_DECOMPRESS
+#ifdef CONFIG_MODULE_STATS
+	unsigned long compressed_len;
+#endif
 	struct page **pages;
 	unsigned int max_pages;
 	unsigned int used_pages;
@@ -101,11 +95,16 @@ int try_to_force_load(struct module *mod, const char *reason);
 bool find_symbol(struct find_symbol_arg *fsa);
 struct module *find_module_all(const char *name, size_t len, bool even_unformed);
 int cmp_name(const void *name, const void *sym);
-long module_get_offset(struct module *mod, unsigned int *size, Elf_Shdr *sechdr,
-		       unsigned int section);
+long module_get_offset_and_type(struct module *mod, enum mod_mem_type type,
+				Elf_Shdr *sechdr, unsigned int section);
 char *module_flags(struct module *mod, char *buf, bool show_state);
 size_t module_flags_taint(unsigned long taints, char *buf);
 
+char *module_next_tag_pair(char *string, unsigned long *secsize);
+
+#define for_each_modinfo_entry(entry, info, name) \
+	for (entry = get_modinfo(info, name); entry; entry = get_next_modinfo(info, name, entry))
+
 static inline void module_assert_mutex_or_preempt(void)
 {
 #ifdef CONFIG_LOCKDEP
@@ -148,6 +147,95 @@ static inline bool set_livepatch_module(struct module *mod)
 #endif
 }
 
+/**
+ * enum fail_dup_mod_reason - state at which a duplicate module was detected
+ *
+ * @FAIL_DUP_MOD_BECOMING: the module is read properly, passes all checks but
+ * 	we've determined that another module with the same name is already loaded
+ * 	or being processed on our &modules list. This happens on early_mod_check()
+ * 	right before layout_and_allocate(). The kernel would have already
+ * 	vmalloc()'d space for the entire module through finit_module(). If
+ * 	decompression was used two vmap() spaces were used. These failures can
+ * 	happen when userspace has not seen the module present on the kernel and
+ * 	tries to load the module multiple times at same time.
+ * @FAIL_DUP_MOD_LOAD: the module has been read properly, passes all validation
+ *	checks and the kernel determines that the module was unique and because
+ *	of this allocated yet another private kernel copy of the module space in
+ *	layout_and_allocate() but after this determined in add_unformed_module()
+ *	that another module with the same name is already loaded or being processed.
+ *	These failures should be mitigated as much as possible and are indicative
+ *	of really fast races in loading modules. Without module decompression
+ *	they waste twice as much vmap space. With module decompression three
+ *	times the module's size vmap space is wasted.
+ */
+enum fail_dup_mod_reason {
+	FAIL_DUP_MOD_BECOMING = 0,
+	FAIL_DUP_MOD_LOAD,
+};
+
+#ifdef CONFIG_MODULE_DEBUGFS
+extern struct dentry *mod_debugfs_root;
+#endif
+
+#ifdef CONFIG_MODULE_STATS
+
+#define mod_stat_add_long(count, var) atomic_long_add(count, var)
+#define mod_stat_inc(name) atomic_inc(name)
+
+extern atomic_long_t total_mod_size;
+extern atomic_long_t total_text_size;
+extern atomic_long_t invalid_kread_bytes;
+extern atomic_long_t invalid_decompress_bytes;
+
+extern atomic_t modcount;
+extern atomic_t failed_kreads;
+extern atomic_t failed_decompress;
+struct mod_fail_load {
+	struct list_head list;
+	char name[MODULE_NAME_LEN];
+	atomic_long_t count;
+	unsigned long dup_fail_mask;
+};
+
+int try_add_failed_module(const char *name, enum fail_dup_mod_reason reason);
+void mod_stat_bump_invalid(struct load_info *info, int flags);
+void mod_stat_bump_becoming(struct load_info *info, int flags);
+
+#else
+
+#define mod_stat_add_long(name, var)
+#define mod_stat_inc(name)
+
+static inline int try_add_failed_module(const char *name,
+					enum fail_dup_mod_reason reason)
+{
+	return 0;
+}
+
+static inline void mod_stat_bump_invalid(struct load_info *info, int flags)
+{
+}
+
+static inline void mod_stat_bump_becoming(struct load_info *info, int flags)
+{
+}
+
+#endif /* CONFIG_MODULE_STATS */
+
+#ifdef CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS
+bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret);
+void kmod_dup_request_announce(char *module_name, int ret);
+#else
+static inline bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret)
+{
+	return false;
+}
+
+static inline void kmod_dup_request_announce(char *module_name, int ret)
+{
+}
+#endif
+
 #ifdef CONFIG_MODULE_UNLOAD_TAINT_TRACKING
 struct mod_unload_taint {
 	struct list_head list;
@@ -190,10 +278,13 @@ struct mod_tree_root {
 #endif
 	unsigned long addr_min;
 	unsigned long addr_max;
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+	unsigned long data_addr_min;
+	unsigned long data_addr_max;
+#endif
 };
 
 extern struct mod_tree_root mod_tree;
-extern struct mod_tree_root mod_data_tree;
 
 #ifdef CONFIG_MODULES_TREE_LOOKUP
 void mod_tree_insert(struct module *mod);
@@ -224,7 +315,6 @@ void module_enable_nx(const struct module *mod);
 void module_enable_x(const struct module *mod);
 int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 				char *secstrings, struct module *mod);
-bool module_check_misalignment(const struct module *mod);
 
 #ifdef CONFIG_MODULE_SIG
 int module_sig_check(struct load_info *info, int flags);