Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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>
+14
-2
+14
-2
fs/open.c
+14
-2
fs/open.c
···
332
332
asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length)
333
333
{
334
334
long ret = do_sys_ftruncate(fd, length, 1);
335
+
/* avoid REGPARM breakage on x86: */
335
336
prevent_tail_call(ret);
336
337
return ret;
337
338
}
···
347
346
asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length)
348
347
{
349
348
long ret = do_sys_ftruncate(fd, length, 0);
349
+
/* avoid REGPARM breakage on x86: */
350
350
prevent_tail_call(ret);
351
351
return ret;
352
352
}
···
1099
1097
1100
1098
asmlinkage long sys_open(const char __user *filename, int flags, int mode)
1101
1099
{
1100
+
long ret;
1101
+
1102
1102
if (force_o_largefile())
1103
1103
flags |= O_LARGEFILE;
1104
1104
1105
-
return do_sys_open(AT_FDCWD, filename, flags, mode);
1105
+
ret = do_sys_open(AT_FDCWD, filename, flags, mode);
1106
+
/* avoid REGPARM breakage on x86: */
1107
+
prevent_tail_call(ret);
1108
+
return ret;
1106
1109
}
1107
1110
EXPORT_SYMBOL_GPL(sys_open);
1108
1111
1109
1112
asmlinkage long sys_openat(int dfd, const char __user *filename, int flags,
1110
1113
int mode)
1111
1114
{
1115
+
long ret;
1116
+
1112
1117
if (force_o_largefile())
1113
1118
flags |= O_LARGEFILE;
1114
1119
1115
-
return do_sys_open(dfd, filename, flags, mode);
1120
+
ret = do_sys_open(dfd, filename, flags, mode);
1121
+
/* avoid REGPARM breakage on x86: */
1122
+
prevent_tail_call(ret);
1123
+
return ret;
1116
1124
}
1117
1125
EXPORT_SYMBOL_GPL(sys_openat);
1118
1126