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authorLinus Torvalds <torvalds@linux-foundation.org>2015-01-23 06:40:36 +1200
committerLinus Torvalds <torvalds@linux-foundation.org>2015-01-23 06:40:36 +1200
commit193934123c84fa168d0326aa6ab8d58cd173b32a (patch)
tree1e2d93840c4e0c49e327d4493913e6c9db861c87
parentb942c653ae265abbd31032f3b4f5f857e5c7c723 (diff)
parentd5db139ab3764640e0882a1746e7b9fdee33fd87 (diff)
downloadlinux-193934123c84fa168d0326aa6ab8d58cd173b32a.tar.gz
Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull module and param fixes from Rusty Russell: "Surprising number of fixes this merge window :( The first two are minor fallout from the param rework which went in this merge window. The next three are a series which fixes a longstanding (but never previously reported and unlikely , so no CC stable) race between kallsyms and freeing the init section. Finally, a minor cleanup as our module refcount will now be -1 during unload" * tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: module: make module_refcount() a signed integer. module: fix race in kallsyms resolution during module load success. module: remove mod arg from module_free, rename module_memfree(). module_arch_freeing_init(): new hook for archs before module->module_init freed. param: fix uninitialized read with CONFIG_DEBUG_LOCK_ALLOC param: initialize store function to NULL if not available.
-rw-r--r--arch/avr32/kernel/module.c13
-rw-r--r--arch/cris/kernel/module.c2
-rw-r--r--arch/ia64/kernel/module.c6
-rw-r--r--arch/mips/net/bpf_jit.c2
-rw-r--r--arch/nios2/kernel/module.c2
-rw-r--r--arch/parisc/kernel/module.c6
-rw-r--r--arch/powerpc/net/bpf_jit_comp.c2
-rw-r--r--arch/s390/kernel/module.c10
-rw-r--r--arch/sparc/net/bpf_jit_comp.c4
-rw-r--r--arch/tile/kernel/module.c4
-rw-r--r--arch/x86/kernel/ftrace.c2
-rw-r--r--include/linux/module.h2
-rw-r--r--include/linux/moduleloader.h4
-rw-r--r--kernel/bpf/core.c2
-rw-r--r--kernel/debug/kdb/kdb_main.c2
-rw-r--r--kernel/kprobes.c2
-rw-r--r--kernel/module.c91
-rw-r--r--kernel/params.c3
18 files changed, 94 insertions, 65 deletions
diff --git a/arch/avr32/kernel/module.c b/arch/avr32/kernel/module.c
index 2c941290802..164efa009e5 100644
--- a/arch/avr32/kernel/module.c
+++ b/arch/avr32/kernel/module.c
@@ -19,12 +19,10 @@
#include <linux/moduleloader.h>
#include <linux/vmalloc.h>
-void module_free(struct module *mod, void *module_region)
+void module_arch_freeing_init(struct module *mod)
{
vfree(mod->arch.syminfo);
mod->arch.syminfo = NULL;
-
- vfree(module_region);
}
static inline int check_rela(Elf32_Rela *rela, struct module *module,
@@ -291,12 +289,3 @@ int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
return ret;
}
-
-int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
- struct module *module)
-{
- vfree(module->arch.syminfo);
- module->arch.syminfo = NULL;
-
- return 0;
-}
diff --git a/arch/cris/kernel/module.c b/arch/cris/kernel/module.c
index 51123f985eb..af04cb6b6dc 100644
--- a/arch/cris/kernel/module.c
+++ b/arch/cris/kernel/module.c
@@ -36,7 +36,7 @@ void *module_alloc(unsigned long size)
}
/* Free memory returned from module_alloc */
-void module_free(struct module *mod, void *module_region)
+void module_memfree(void *module_region)
{
kfree(module_region);
}
diff --git a/arch/ia64/kernel/module.c b/arch/ia64/kernel/module.c
index 24603be24c1..29754aae517 100644
--- a/arch/ia64/kernel/module.c
+++ b/arch/ia64/kernel/module.c
@@ -305,14 +305,12 @@ plt_target (struct plt_entry *plt)
#endif /* !USE_BRL */
void
-module_free (struct module *mod, void *module_region)
+module_arch_freeing_init (struct module *mod)
{
- if (mod && mod->arch.init_unw_table &&
- module_region == mod->module_init) {
+ if (mod->arch.init_unw_table) {
unw_remove_unwind_table(mod->arch.init_unw_table);
mod->arch.init_unw_table = NULL;
}
- vfree(module_region);
}
/* Have we already seen one of these relocations? */
diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
index 9fd6834a217..5d6139390bf 100644
--- a/arch/mips/net/bpf_jit.c
+++ b/arch/mips/net/bpf_jit.c
@@ -1388,7 +1388,7 @@ out:
void bpf_jit_free(struct bpf_prog *fp)
{
if (fp->jited)
- module_free(NULL, fp->bpf_func);
+ module_memfree(fp->bpf_func);
bpf_prog_unlock_free(fp);
}
diff --git a/arch/nios2/kernel/module.c b/arch/nios2/kernel/module.c
index cc924a38f22..e2e3f13f98d 100644
--- a/arch/nios2/kernel/module.c
+++ b/arch/nios2/kernel/module.c
@@ -36,7 +36,7 @@ void *module_alloc(unsigned long size)
}
/* Free memory returned from module_alloc */
-void module_free(struct module *mod, void *module_region)
+void module_memfree(void *module_region)
{
kfree(module_region);
}
diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index 50dfafc3f2c..5822e8e200e 100644
--- a/arch/parisc/kernel/module.c
+++ b/arch/parisc/kernel/module.c
@@ -298,14 +298,10 @@ static inline unsigned long count_stubs(const Elf_Rela *rela, unsigned long n)
}
#endif
-
-/* Free memory returned from module_alloc */
-void module_free(struct module *mod, void *module_region)
+void module_arch_freeing_init(struct module *mod)
{
kfree(mod->arch.section);
mod->arch.section = NULL;
-
- vfree(module_region);
}
/* Additional bytes needed in front of individual sections */
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 1ca125b9c22..d1916b577f2 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -699,7 +699,7 @@ out:
void bpf_jit_free(struct bpf_prog *fp)
{
if (fp->jited)
- module_free(NULL, fp->bpf_func);
+ module_memfree(fp->bpf_func);
bpf_prog_unlock_free(fp);
}
diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
index b89b59158b9..409d152585b 100644
--- a/arch/s390/kernel/module.c
+++ b/arch/s390/kernel/module.c
@@ -55,14 +55,10 @@ void *module_alloc(unsigned long size)
}
#endif
-/* Free memory returned from module_alloc */
-void module_free(struct module *mod, void *module_region)
+void module_arch_freeing_init(struct module *mod)
{
- if (mod) {
- vfree(mod->arch.syminfo);
- mod->arch.syminfo = NULL;
- }
- vfree(module_region);
+ vfree(mod->arch.syminfo);
+ mod->arch.syminfo = NULL;
}
static void check_rela(Elf_Rela *rela, struct module *me)
diff --git a/arch/sparc/net/bpf_jit_comp.c b/arch/sparc/net/bpf_jit_comp.c
index f33e7c7a3bf..7931eeeb649 100644
--- a/arch/sparc/net/bpf_jit_comp.c
+++ b/arch/sparc/net/bpf_jit_comp.c
@@ -776,7 +776,7 @@ cond_branch: f_offset = addrs[i + filter[i].jf];
if (unlikely(proglen + ilen > oldproglen)) {
pr_err("bpb_jit_compile fatal error\n");
kfree(addrs);
- module_free(NULL, image);
+ module_memfree(image);
return;
}
memcpy(image + proglen, temp, ilen);
@@ -822,7 +822,7 @@ out:
void bpf_jit_free(struct bpf_prog *fp)
{
if (fp->jited)
- module_free(NULL, fp->bpf_func);
+ module_memfree(fp->bpf_func);
bpf_prog_unlock_free(fp);
}
diff --git a/arch/tile/kernel/module.c b/arch/tile/kernel/module.c
index 96447c9160a..2305084c9b9 100644
--- a/arch/tile/kernel/module.c
+++ b/arch/tile/kernel/module.c
@@ -74,7 +74,7 @@ error:
/* Free memory returned from module_alloc */
-void module_free(struct module *mod, void *module_region)
+void module_memfree(void *module_region)
{
vfree(module_region);
@@ -83,7 +83,7 @@ void module_free(struct module *mod, void *module_region)
0, 0, 0, NULL, NULL, 0);
/*
- * FIXME: If module_region == mod->module_init, trim exception
+ * FIXME: Add module_arch_freeing_init to trim exception
* table entries.
*/
}
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 2142376dc8c..8b7b0a51e74 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -674,7 +674,7 @@ static inline void *alloc_tramp(unsigned long size)
}
static inline void tramp_free(void *tramp)
{
- module_free(NULL, tramp);
+ module_memfree(tramp);
}
#else
/* Trampolines can only be created if modules are supported */
diff --git a/include/linux/module.h b/include/linux/module.h
index ebfb0e153c6..b653d7c0a05 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -444,7 +444,7 @@ extern void __module_put_and_exit(struct module *mod, long code)
#define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code)
#ifdef CONFIG_MODULE_UNLOAD
-unsigned long module_refcount(struct module *mod);
+int module_refcount(struct module *mod);
void __symbol_put(const char *symbol);
#define symbol_put(x) __symbol_put(VMLINUX_SYMBOL_STR(x))
void symbol_put_addr(void *addr);
diff --git a/include/linux/moduleloader.h b/include/linux/moduleloader.h
index 7eeb9bbfb81..f7556261fe3 100644
--- a/include/linux/moduleloader.h
+++ b/include/linux/moduleloader.h
@@ -26,7 +26,7 @@ unsigned int arch_mod_section_prepend(struct module *mod, unsigned int section);
void *module_alloc(unsigned long size);
/* Free memory returned from module_alloc. */
-void module_free(struct module *mod, void *module_region);
+void module_memfree(void *module_region);
/*
* Apply the given relocation to the (simplified) ELF. Return -error
@@ -82,4 +82,6 @@ int module_finalize(const Elf_Ehdr *hdr,
/* Any cleanup needed when module leaves. */
void module_arch_cleanup(struct module *mod);
+/* Any cleanup before freeing mod->module_init */
+void module_arch_freeing_init(struct module *mod);
#endif
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index d6594e457a2..a64e7a207d2 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -163,7 +163,7 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
void bpf_jit_binary_free(struct bpf_binary_header *hdr)
{
- module_free(NULL, hdr);
+ module_memfree(hdr);
}
#endif /* CONFIG_BPF_JIT */
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index f191bddf64b..7b40c5f07dc 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -2023,7 +2023,7 @@ static int kdb_lsmod(int argc, const char **argv)
kdb_printf("%-20s%8u 0x%p ", mod->name,
mod->core_size, (void *)mod);
#ifdef CONFIG_MODULE_UNLOAD
- kdb_printf("%4ld ", module_refcount(mod));
+ kdb_printf("%4d ", module_refcount(mod));
#endif
if (mod->state == MODULE_STATE_GOING)
kdb_printf(" (Unloading)");
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 06f58309fed..ee619929cf9 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -127,7 +127,7 @@ static void *alloc_insn_page(void)
static void free_insn_page(void *page)
{
- module_free(NULL, page);
+ module_memfree(page);
}
struct kprobe_insn_cache kprobe_insn_slots = {
diff --git a/kernel/module.c b/kernel/module.c
index 3965511ae13..d856e96a3cc 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -772,9 +772,18 @@ static int try_stop_module(struct module *mod, int flags, int *forced)
return 0;
}
-unsigned long module_refcount(struct module *mod)
+/**
+ * module_refcount - return the refcount or -1 if unloading
+ *
+ * @mod: the module we're checking
+ *
+ * Returns:
+ * -1 if the module is in the process of unloading
+ * otherwise the number of references in the kernel to the module
+ */
+int module_refcount(struct module *mod)
{
- return (unsigned long)atomic_read(&mod->refcnt) - MODULE_REF_BASE;
+ return atomic_read(&mod->refcnt) - MODULE_REF_BASE;
}
EXPORT_SYMBOL(module_refcount);
@@ -856,7 +865,7 @@ static inline void print_unload_info(struct seq_file *m, struct module *mod)
struct module_use *use;
int printed_something = 0;
- seq_printf(m, " %lu ", module_refcount(mod));
+ seq_printf(m, " %i ", module_refcount(mod));
/*
* Always include a trailing , so userspace can differentiate
@@ -908,7 +917,7 @@ EXPORT_SYMBOL_GPL(symbol_put_addr);
static ssize_t show_refcnt(struct module_attribute *mattr,
struct module_kobject *mk, char *buffer)
{
- return sprintf(buffer, "%lu\n", module_refcount(mk->mod));
+ return sprintf(buffer, "%i\n", module_refcount(mk->mod));
}
static struct module_attribute modinfo_refcnt =
@@ -1795,7 +1804,7 @@ static void unset_module_core_ro_nx(struct module *mod) { }
static void unset_module_init_ro_nx(struct module *mod) { }
#endif
-void __weak module_free(struct module *mod, void *module_region)
+void __weak module_memfree(void *module_region)
{
vfree(module_region);
}
@@ -1804,6 +1813,10 @@ void __weak module_arch_cleanup(struct module *mod)
{
}
+void __weak module_arch_freeing_init(struct module *mod)
+{
+}
+
/* Free a module, remove from lists, etc. */
static void free_module(struct module *mod)
{
@@ -1841,7 +1854,8 @@ static void free_module(struct module *mod)
/* This may be NULL, but that's OK */
unset_module_init_ro_nx(mod);
- module_free(mod, mod->module_init);
+ module_arch_freeing_init(mod);
+ module_memfree(mod->module_init);
kfree(mod->args);
percpu_modfree(mod);
@@ -1850,7 +1864,7 @@ static void free_module(struct module *mod)
/* Finally, free the core (containing the module structure) */
unset_module_core_ro_nx(mod);
- module_free(mod, mod->module_core);
+ module_memfree(mod->module_core);
#ifdef CONFIG_MPU
update_protections(current->mm);
@@ -2785,7 +2799,7 @@ static int move_module(struct module *mod, struct load_info *info)
*/
kmemleak_ignore(ptr);
if (!ptr) {
- module_free(mod, mod->module_core);
+ module_memfree(mod->module_core);
return -ENOMEM;
}
memset(ptr, 0, mod->init_size);
@@ -2930,8 +2944,9 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
static void module_deallocate(struct module *mod, struct load_info *info)
{
percpu_modfree(mod);
- module_free(mod, mod->module_init);
- module_free(mod, mod->module_core);
+ module_arch_freeing_init(mod);
+ module_memfree(mod->module_init);
+ module_memfree(mod->module_core);
}
int __weak module_finalize(const Elf_Ehdr *hdr,
@@ -2983,10 +2998,31 @@ static void do_mod_ctors(struct module *mod)
#endif
}
+/* For freeing module_init on success, in case kallsyms traversing */
+struct mod_initfree {
+ struct rcu_head rcu;
+ void *module_init;
+};
+
+static void do_free_init(struct rcu_head *head)
+{
+ struct mod_initfree *m = container_of(head, struct mod_initfree, rcu);
+ module_memfree(m->module_init);
+ kfree(m);
+}
+
/* This is where the real work happens */
static int do_init_module(struct module *mod)
{
int ret = 0;
+ struct mod_initfree *freeinit;
+
+ freeinit = kmalloc(sizeof(*freeinit), GFP_KERNEL);
+ if (!freeinit) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+ freeinit->module_init = mod->module_init;
/*
* We want to find out whether @mod uses async during init. Clear
@@ -2999,18 +3035,7 @@ static int do_init_module(struct module *mod)
if (mod->init != NULL)
ret = do_one_initcall(mod->init);
if (ret < 0) {
- /*
- * Init routine failed: abort. Try to protect us from
- * buggy refcounters.
- */
- mod->state = MODULE_STATE_GOING;
- synchronize_sched();
- module_put(mod);
- blocking_notifier_call_chain(&module_notify_list,
- MODULE_STATE_GOING, mod);
- free_module(mod);
- wake_up_all(&module_wq);
- return ret;
+ goto fail_free_freeinit;
}
if (ret > 0) {
pr_warn("%s: '%s'->init suspiciously returned %d, it should "
@@ -3055,15 +3080,35 @@ static int do_init_module(struct module *mod)
mod->strtab = mod->core_strtab;
#endif
unset_module_init_ro_nx(mod);
- module_free(mod, mod->module_init);
+ module_arch_freeing_init(mod);
mod->module_init = NULL;
mod->init_size = 0;
mod->init_ro_size = 0;
mod->init_text_size = 0;
+ /*
+ * We want to free module_init, but be aware that kallsyms may be
+ * walking this with preempt disabled. In all the failure paths,
+ * we call synchronize_rcu/synchronize_sched, but we don't want
+ * to slow down the success path, so use actual RCU here.
+ */
+ call_rcu(&freeinit->rcu, do_free_init);
mutex_unlock(&module_mutex);
wake_up_all(&module_wq);
return 0;
+
+fail_free_freeinit:
+ kfree(freeinit);
+fail:
+ /* Try to protect us from buggy refcounters. */
+ mod->state = MODULE_STATE_GOING;
+ synchronize_sched();
+ module_put(mod);
+ blocking_notifier_call_chain(&module_notify_list,
+ MODULE_STATE_GOING, mod);
+ free_module(mod);
+ wake_up_all(&module_wq);
+ return ret;
}
static int may_init_module(void)
diff --git a/kernel/params.c b/kernel/params.c
index 0af9b2c4e56..728e05b167d 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -642,12 +642,15 @@ static __modinit int add_sysfs_param(struct module_kobject *mk,
mk->mp->grp.attrs = new_attrs;
/* Tack new one on the end. */
+ memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
mk->mp->attrs[mk->mp->num].param = kp;
mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
/* Do not allow runtime DAC changes to make param writable. */
if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
+ else
+ mk->mp->attrs[mk->mp->num].mattr.store = NULL;
mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
mk->mp->num++;