Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 385910f2 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

x86: be careful about tailcall breakage for sys_open[at] too 



Came up through a quick grep for other cases similar to the ftruncate()
one in commit 0a489cb3.

Also, add a comment, so that people who read the code understand why we
do what looks like a no-op.

(Again, this won't actually matter to any sane user, since libc will
save and restore the register gcc stomps on, but it's still wrong to
stomp on it)

Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0a489cb3

fs/open.c

+14 −2
Original line number Diff line number Diff line
@@ -332,6 +332,7 @@ static long do_sys_ftruncate(unsigned int fd, loff_t length, int small) 
asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length)

{

	long ret = do_sys_ftruncate(fd, length, 1);

	/* avoid REGPARM breakage on x86: */

	prevent_tail_call(ret);

	return ret;

}
@@ -346,6 +347,7 @@ asmlinkage long sys_truncate64(const char __user * path, loff_t length) 
asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length)

{

	long ret = do_sys_ftruncate(fd, length, 0);

	/* avoid REGPARM breakage on x86: */

	prevent_tail_call(ret);

	return ret;

}
@@ -1097,20 +1099,30 @@ long do_sys_open(int dfd, const char __user *filename, int flags, int mode) 


asmlinkage long sys_open(const char __user *filename, int flags, int mode)

{

	long ret;



	if (force_o_largefile())

		flags |= O_LARGEFILE;



	return do_sys_open(AT_FDCWD, filename, flags, mode);

	ret = do_sys_open(AT_FDCWD, filename, flags, mode);

	/* avoid REGPARM breakage on x86: */

	prevent_tail_call(ret);

	return ret;

}

EXPORT_SYMBOL_GPL(sys_open);



asmlinkage long sys_openat(int dfd, const char __user *filename, int flags,

			   int mode)

{

	long ret;



	if (force_o_largefile())

		flags |= O_LARGEFILE;



	return do_sys_open(dfd, filename, flags, mode);

	ret = do_sys_open(dfd, filename, flags, mode);

	/* avoid REGPARM breakage on x86: */

	prevent_tail_call(ret);

	return ret;

}

EXPORT_SYMBOL_GPL(sys_openat);