aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2010-10-05 11:29:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-05 11:29:27 -0700
commit5336377d6225959624146629ce3fc88ee8ecda3d (patch)
tree571b9db75d1ba50faa1e399509563f367fd5694f
parent2f6b3aa7a563d05453c4d73ccf88191aee84333f (diff)
modules: Fix module_bug_list list corruption race
With all the recent module loading cleanups, we've minimized the code that sits under module_mutex, fixing various deadlocks and making it possible to do most of the module loading in parallel. However, that whole conversion totally missed the rather obscure code that adds a new module to the list for BUG() handling. That code was doubly obscure because (a) the code itself lives in lib/bugs.c (for dubious reasons) and (b) it gets called from the architecture-specific "module_finalize()" rather than from generic code. Calling it from arch-specific code makes no sense what-so-ever to begin with, and is now actively wrong since that code isn't protected by the module loading lock any more. So this commit moves the "module_bug_{finalize,cleanup}()" calls away from the arch-specific code, and into the generic code - and in the process protects it with the module_mutex so that the list operations are now safe. Future fixups: - move the module list handling code into kernel/module.c where it belongs. - get rid of 'module_bug_list' and just use the regular list of modules (called 'modules' - imagine that) that we already create and maintain for other reasons. Reported-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Adrian Bunk <bunk@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/avr32/kernel/module.c3
-rw-r--r--arch/h8300/kernel/module.c3
-rw-r--r--arch/mn10300/kernel/module.c3
-rw-r--r--arch/parisc/kernel/module.c3
-rw-r--r--arch/powerpc/kernel/module.c5
-rw-r--r--arch/s390/kernel/module.c3
-rw-r--r--arch/sh/kernel/module.c2
-rw-r--r--arch/x86/kernel/module.c3
-rw-r--r--include/linux/module.h5
-rw-r--r--kernel/module.c4
-rw-r--r--lib/bug.c6
11 files changed, 14 insertions, 26 deletions
diff --git a/arch/avr32/kernel/module.c b/arch/avr32/kernel/module.c
index 98f94d041d9c..a727f54d64d6 100644
--- a/arch/avr32/kernel/module.c
+++ b/arch/avr32/kernel/module.c
@@ -314,10 +314,9 @@ int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
vfree(module->arch.syminfo);
module->arch.syminfo = NULL;
- return module_bug_finalize(hdr, sechdrs, module);
+ return 0;
}
void module_arch_cleanup(struct module *module)
{
- module_bug_cleanup(module);
}
diff --git a/arch/h8300/kernel/module.c b/arch/h8300/kernel/module.c
index 0865e291c20d..db4953dc4e1b 100644
--- a/arch/h8300/kernel/module.c
+++ b/arch/h8300/kernel/module.c
@@ -112,10 +112,9 @@ int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *me)
{
- return module_bug_finalize(hdr, sechdrs, me);
+ return 0;
}
void module_arch_cleanup(struct module *mod)
{
- module_bug_cleanup(mod);
}
diff --git a/arch/mn10300/kernel/module.c b/arch/mn10300/kernel/module.c
index 6aea7fd76993..196a111e2e29 100644
--- a/arch/mn10300/kernel/module.c
+++ b/arch/mn10300/kernel/module.c
@@ -206,7 +206,7 @@ int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *me)
{
- return module_bug_finalize(hdr, sechdrs, me);
+ return 0;
}
/*
@@ -214,5 +214,4 @@ int module_finalize(const Elf_Ehdr *hdr,
*/
void module_arch_cleanup(struct module *mod)
{
- module_bug_cleanup(mod);
}
diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index 159a2b81e90c..6e81bb596e5b 100644
--- a/arch/parisc/kernel/module.c
+++ b/arch/parisc/kernel/module.c
@@ -941,11 +941,10 @@ int module_finalize(const Elf_Ehdr *hdr,
nsyms = newptr - (Elf_Sym *)symhdr->sh_addr;
DEBUGP("NEW num_symtab %lu\n", nsyms);
symhdr->sh_size = nsyms * sizeof(Elf_Sym);
- return module_bug_finalize(hdr, sechdrs, me);
+ return 0;
}
void module_arch_cleanup(struct module *mod)
{
deregister_unwind_table(mod);
- module_bug_cleanup(mod);
}
diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
index 477c663e0140..4ef93ae2235f 100644
--- a/arch/powerpc/kernel/module.c
+++ b/arch/powerpc/kernel/module.c
@@ -65,10 +65,6 @@ int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sect;
int err;
- err = module_bug_finalize(hdr, sechdrs, me);
- if (err)
- return err;
-
/* Apply feature fixups */
sect = find_section(hdr, sechdrs, "__ftr_fixup");
if (sect != NULL)
@@ -101,5 +97,4 @@ int module_finalize(const Elf_Ehdr *hdr,
void module_arch_cleanup(struct module *mod)
{
- module_bug_cleanup(mod);
}
diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
index 22cfd634c355..f7167ee4604c 100644
--- a/arch/s390/kernel/module.c
+++ b/arch/s390/kernel/module.c
@@ -407,10 +407,9 @@ int module_finalize(const Elf_Ehdr *hdr,
{
vfree(me->arch.syminfo);
me->arch.syminfo = NULL;
- return module_bug_finalize(hdr, sechdrs, me);
+ return 0;
}
void module_arch_cleanup(struct module *mod)
{
- module_bug_cleanup(mod);
}
diff --git a/arch/sh/kernel/module.c b/arch/sh/kernel/module.c
index 43adddfe4c04..ae0be697a89e 100644
--- a/arch/sh/kernel/module.c
+++ b/arch/sh/kernel/module.c
@@ -149,13 +149,11 @@ int module_finalize(const Elf_Ehdr *hdr,
int ret = 0;
ret |= module_dwarf_finalize(hdr, sechdrs, me);
- ret |= module_bug_finalize(hdr, sechdrs, me);
return ret;
}
void module_arch_cleanup(struct module *mod)
{
- module_bug_cleanup(mod);
module_dwarf_cleanup(mod);
}
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index e0bc186d7501..1c355c550960 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -239,11 +239,10 @@ int module_finalize(const Elf_Ehdr *hdr,
apply_paravirt(pseg, pseg + para->sh_size);
}
- return module_bug_finalize(hdr, sechdrs, me);
+ return 0;
}
void module_arch_cleanup(struct module *mod)
{
alternatives_smp_module_del(mod);
- module_bug_cleanup(mod);
}
diff --git a/include/linux/module.h b/include/linux/module.h
index 8a6b9fdc7ffa..aace066bad8f 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -686,17 +686,16 @@ extern int module_sysfs_initialized;
#ifdef CONFIG_GENERIC_BUG
-int module_bug_finalize(const Elf_Ehdr *, const Elf_Shdr *,
+void module_bug_finalize(const Elf_Ehdr *, const Elf_Shdr *,
struct module *);
void module_bug_cleanup(struct module *);
#else /* !CONFIG_GENERIC_BUG */
-static inline int module_bug_finalize(const Elf_Ehdr *hdr,
+static inline void module_bug_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *mod)
{
- return 0;
}
static inline void module_bug_cleanup(struct module *mod) {}
#endif /* CONFIG_GENERIC_BUG */
diff --git a/kernel/module.c b/kernel/module.c
index d0b5f8db11b4..ccd641991842 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1537,6 +1537,7 @@ static int __unlink_module(void *_mod)
{
struct module *mod = _mod;
list_del(&mod->list);
+ module_bug_cleanup(mod);
return 0;
}
@@ -2625,6 +2626,7 @@ static struct module *load_module(void __user *umod,
if (err < 0)
goto ddebug;
+ module_bug_finalize(info.hdr, info.sechdrs, mod);
list_add_rcu(&mod->list, &modules);
mutex_unlock(&module_mutex);
@@ -2650,6 +2652,8 @@ static struct module *load_module(void __user *umod,
mutex_lock(&module_mutex);
/* Unlink carefully: kallsyms could be walking list. */
list_del_rcu(&mod->list);
+ module_bug_cleanup(mod);
+
ddebug:
if (!mod->taints)
dynamic_debug_remove(info.debug);
diff --git a/lib/bug.c b/lib/bug.c
index 7cdfad88128f..19552096d16b 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -72,8 +72,8 @@ static const struct bug_entry *module_find_bug(unsigned long bugaddr)
return NULL;
}
-int module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
- struct module *mod)
+void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
+ struct module *mod)
{
char *secstrings;
unsigned int i;
@@ -97,8 +97,6 @@ int module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
* could potentially lead to deadlock and thus be counter-productive.
*/
list_add(&mod->bug_list, &module_bug_list);
-
- return 0;
}
void module_bug_cleanup(struct module *mod)

Privacy Policy