diff options
author | Paul Mackerras <paulus@samba.org> | 2009-01-06 17:41:02 -0500 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-06 18:59:13 -0500 |
commit | e3d5a27d5862b6425d0879272e24abecf7245105 (patch) | |
tree | c8a873e926d4768ae2ecac50c46c5121c8472876 /kernel | |
parent | af9379c7121d5543722c00bbd1adf7dcaa0b6448 (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')
-rw-r--r-- | kernel/compat.c | 5 | ||||
-rw-r--r-- | kernel/sys.c | 2 | ||||
-rw-r--r-- | kernel/time.c | 4 |
3 files changed, 9 insertions, 2 deletions
diff --git a/kernel/compat.c b/kernel/compat.c index d52e2ec1deb5..42d56544460f 100644 --- a/kernel/compat.c +++ b/kernel/compat.c | |||
@@ -24,6 +24,7 @@ | |||
24 | #include <linux/migrate.h> | 24 | #include <linux/migrate.h> |
25 | #include <linux/posix-timers.h> | 25 | #include <linux/posix-timers.h> |
26 | #include <linux/times.h> | 26 | #include <linux/times.h> |
27 | #include <linux/ptrace.h> | ||
27 | 28 | ||
28 | #include <asm/uaccess.h> | 29 | #include <asm/uaccess.h> |
29 | 30 | ||
@@ -229,6 +230,7 @@ asmlinkage long compat_sys_times(struct compat_tms __user *tbuf) | |||
229 | if (copy_to_user(tbuf, &tmp, sizeof(tmp))) | 230 | if (copy_to_user(tbuf, &tmp, sizeof(tmp))) |
230 | return -EFAULT; | 231 | return -EFAULT; |
231 | } | 232 | } |
233 | force_successful_syscall_return(); | ||
232 | return compat_jiffies_to_clock_t(jiffies); | 234 | return compat_jiffies_to_clock_t(jiffies); |
233 | } | 235 | } |
234 | 236 | ||
@@ -894,8 +896,9 @@ asmlinkage long compat_sys_time(compat_time_t __user * tloc) | |||
894 | 896 | ||
895 | if (tloc) { | 897 | if (tloc) { |
896 | if (put_user(i,tloc)) | 898 | if (put_user(i,tloc)) |
897 | i = -EFAULT; | 899 | return -EFAULT; |
898 | } | 900 | } |
901 | force_successful_syscall_return(); | ||
899 | return i; | 902 | return i; |
900 | } | 903 | } |
901 | 904 | ||
diff --git a/kernel/sys.c b/kernel/sys.c index d356d79e84ac..4a43617cd565 100644 --- a/kernel/sys.c +++ b/kernel/sys.c | |||
@@ -33,6 +33,7 @@ | |||
33 | #include <linux/task_io_accounting_ops.h> | 33 | #include <linux/task_io_accounting_ops.h> |
34 | #include <linux/seccomp.h> | 34 | #include <linux/seccomp.h> |
35 | #include <linux/cpu.h> | 35 | #include <linux/cpu.h> |
36 | #include <linux/ptrace.h> | ||
36 | 37 | ||
37 | #include <linux/compat.h> | 38 | #include <linux/compat.h> |
38 | #include <linux/syscalls.h> | 39 | #include <linux/syscalls.h> |
@@ -927,6 +928,7 @@ asmlinkage long sys_times(struct tms __user * tbuf) | |||
927 | if (copy_to_user(tbuf, &tmp, sizeof(struct tms))) | 928 | if (copy_to_user(tbuf, &tmp, sizeof(struct tms))) |
928 | return -EFAULT; | 929 | return -EFAULT; |
929 | } | 930 | } |
931 | force_successful_syscall_return(); | ||
930 | return (long) jiffies_64_to_clock_t(get_jiffies_64()); | 932 | return (long) jiffies_64_to_clock_t(get_jiffies_64()); |
931 | } | 933 | } |
932 | 934 | ||
diff --git a/kernel/time.c b/kernel/time.c index d63a4336fad6..4886e3ce83a4 100644 --- a/kernel/time.c +++ b/kernel/time.c | |||
@@ -37,6 +37,7 @@ | |||
37 | #include <linux/fs.h> | 37 | #include <linux/fs.h> |
38 | #include <linux/slab.h> | 38 | #include <linux/slab.h> |
39 | #include <linux/math64.h> | 39 | #include <linux/math64.h> |
40 | #include <linux/ptrace.h> | ||
40 | 41 | ||
41 | #include <asm/uaccess.h> | 42 | #include <asm/uaccess.h> |
42 | #include <asm/unistd.h> | 43 | #include <asm/unistd.h> |
@@ -65,8 +66,9 @@ asmlinkage long sys_time(time_t __user * tloc) | |||
65 | 66 | ||
66 | if (tloc) { | 67 | if (tloc) { |
67 | if (put_user(i,tloc)) | 68 | if (put_user(i,tloc)) |
68 | i = -EFAULT; | 69 | return -EFAULT; |
69 | } | 70 | } |
71 | force_successful_syscall_return(); | ||
70 | return i; | 72 | return i; |
71 | } | 73 | } |
72 | 74 | ||