path: root/kernel/compat.c
diff options
authorPaul Mackerras <paulus@samba.org>2009-01-06 14:41:02 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-06 15:59:13 -0800
commite3d5a27d5862b6425d0879272e24abecf7245105 (patch)
treec8a873e926d4768ae2ecac50c46c5121c8472876 /kernel/compat.c
parentaf9379c7121d5543722c00bbd1adf7dcaa0b6448 (diff)
Allow times and time system calls to return small negative values
At the moment, the times() system call will appear to fail for a period shortly after boot, while the value it want to return is between -4095 and -1. The same thing will also happen for the time() system call on 32-bit platforms some time in 2106 or so. On some platforms, such as x86, this is unavoidable because of the system call ABI, but other platforms such as powerpc have a separate error indication from the return value, so system calls can in fact return small negative values without indicating an error. On those platforms, force_successful_syscall_return() provides a way to indicate that the system call return value should not be treated as an error even if it is in the range which would normally be taken as a negative error number. This adds a force_successful_syscall_return() call to the time() and times() system calls plus their 32-bit compat versions, so that they don't erroneously indicate an error on those platforms whose system call ABI has a separate error indication. This will not affect anything on other platforms. Joakim Tjernlund added the fix for time() and the compat versions of time() and times(), after I did the fix for times(). Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: David S. Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/compat.c')
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/compat.c b/kernel/compat.c
index d52e2ec1deb..42d56544460 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -24,6 +24,7 @@
#include <linux/migrate.h>
#include <linux/posix-timers.h>
#include <linux/times.h>
+#include <linux/ptrace.h>
#include <asm/uaccess.h>
@@ -229,6 +230,7 @@ asmlinkage long compat_sys_times(struct compat_tms __user *tbuf)
if (copy_to_user(tbuf, &tmp, sizeof(tmp)))
return -EFAULT;
+ force_successful_syscall_return();
return compat_jiffies_to_clock_t(jiffies);
@@ -894,8 +896,9 @@ asmlinkage long compat_sys_time(compat_time_t __user * tloc)
if (tloc) {
if (put_user(i,tloc))
- i = -EFAULT;
+ return -EFAULT;
+ force_successful_syscall_return();
return i;