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Commit 74641f58 authored by Ivan Kokshaysky's avatar Ivan Kokshaysky Committed by Linus Torvalds
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alpha: binfmt_aout fix 



This fixes the problem introduced by commit 3bfacef4 (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: default avatarIvan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Richard Henderson <rth@twiddle.net
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 77b4cf5c

arch/alpha/kernel/Makefile

+5 −1
Original line number Diff line number Diff line
@@ -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

arch/alpha/kernel/binfmt_loader.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

fs/exec.c

+4 −3
Original line number Diff line number Diff line
@@ -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)

{

include/linux/binfmts.h

+13 −1
Original line number Diff line number Diff line
@@ -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 *);