From 385910f2b275a636238f70844f1b6da9fda6f2da Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 18 Apr 2006 13:22:59 -0700 Subject: [PATCH] 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 0a489cb3b6a7b277030cdbc97c2c65905db94536. 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: Linus Torvalds --- fs/open.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/fs/open.c b/fs/open.c index 8279c65d3bef..53ec28c36777 100644 --- a/fs/open.c +++ b/fs/open.c @@ -332,6 +332,7 @@ out: 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); -- 2.30.2