Messages in this thread Patch in this message | | | Date | Thu, 20 Apr 2006 21:39:45 -0700 | From | Greg KH <> | Subject | [patch 14/22] x86: be careful about tailcall breakage for sys_opentoo |
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From: Linus Torvalds <torvalds@osdl.org>
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 <torvalds@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/open.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)
--- linux-2.6.16.9.orig/fs/open.c +++ linux-2.6.16.9/fs/open.c @@ -331,6 +331,7 @@ 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; } @@ -345,6 +346,7 @@ asmlinkage long sys_truncate64(const cha 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; } @@ -1087,20 +1089,30 @@ long do_sys_open(int dfd, const char __u 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); -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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