alpha: binfmt_aout fix

This fixes the problem introduced by commit 3bfacef412 (get rid of
special-casing the /sbin/loader on alpha): osf/1 ecoff binary segfaults
when binfmt_aout built as module.  That happens because aout binary
handler gets on the top of the binfmt list due to late registration, and
kernel attempts to execute the binary without preparatory work that must
be done by binfmt_loader.

Fixed by changing the registration order of the default binfmt handlers
using list_add_tail() and introducing insert_binfmt() function which
places new handler on the top of the binfmt list.  This might be generally
useful for installing arch-specific frontends for default handlers or just
for overriding them.

Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Richard Henderson <rth@twiddle.net
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ivan Kokshaysky 2009-04-30 15:08:49 -07:00 committed by Linus Torvalds
parent 77b4cf5cb0
commit 74641f584d
4 changed files with 23 additions and 6 deletions

View file

@ -8,7 +8,7 @@ EXTRA_CFLAGS := -Werror -Wno-sign-compare
obj-y := entry.o traps.o process.o init_task.o osf_sys.o irq.o \
irq_alpha.o signal.o setup.o ptrace.o time.o \
alpha_ksyms.o systbls.o err_common.o io.o binfmt_loader.o
alpha_ksyms.o systbls.o err_common.o io.o
obj-$(CONFIG_VGA_HOSE) += console.o
obj-$(CONFIG_SMP) += smp.o
@ -43,6 +43,10 @@ else
# Misc support
obj-$(CONFIG_ALPHA_SRM) += srmcons.o
ifdef CONFIG_BINFMT_AOUT
obj-y += binfmt_loader.o
endif
# Core logic support
obj-$(CONFIG_ALPHA_APECS) += core_apecs.o
obj-$(CONFIG_ALPHA_CIA) += core_cia.o

View file

@ -46,6 +46,6 @@ static struct linux_binfmt loader_format = {
static int __init init_loader_binfmt(void)
{
return register_binfmt(&loader_format);
return insert_binfmt(&loader_format);
}
arch_initcall(init_loader_binfmt);

View file

@ -69,17 +69,18 @@ int suid_dumpable = 0;
static LIST_HEAD(formats);
static DEFINE_RWLOCK(binfmt_lock);
int register_binfmt(struct linux_binfmt * fmt)
int __register_binfmt(struct linux_binfmt * fmt, int insert)
{
if (!fmt)
return -EINVAL;
write_lock(&binfmt_lock);
list_add(&fmt->lh, &formats);
insert ? list_add(&fmt->lh, &formats) :
list_add_tail(&fmt->lh, &formats);
write_unlock(&binfmt_lock);
return 0;
}
EXPORT_SYMBOL(register_binfmt);
EXPORT_SYMBOL(__register_binfmt);
void unregister_binfmt(struct linux_binfmt * fmt)
{

View file

@ -82,7 +82,19 @@ struct linux_binfmt {
int hasvdso;
};
extern int register_binfmt(struct linux_binfmt *);
extern int __register_binfmt(struct linux_binfmt *fmt, int insert);
/* Registration of default binfmt handlers */
static inline int register_binfmt(struct linux_binfmt *fmt)
{
return __register_binfmt(fmt, 0);
}
/* Same as above, but adds a new binfmt at the top of the list */
static inline int insert_binfmt(struct linux_binfmt *fmt)
{
return __register_binfmt(fmt, 1);
}
extern void unregister_binfmt(struct linux_binfmt *);
extern int prepare_binprm(struct linux_binprm *);