Re: sys_times() return value

From: Russell King (rmk+lkml_at_arm.linux.org.uk)
Date: 07/29/05

  • Next message: Michael Kerrisk: "Re: Broke nice range for RLIMIT NICE" 
    Date:	Fri, 29 Jul 2005 11:37:55 +0100
To: Andrew Morton <akpm@osdl.org>

    On Sat, Jul 23, 2005 at 03:35:31PM +1000, Andrew Morton wrote:
    > Russell King <rmk+lkml@arm.linux.org.uk> wrote:
    > > ARM folk have recently pointed out a problem with sys_times().
    > > When the kernel boots, we set jiffies to -5 minutes. This causes
    > > sys_times() to return a negative number, which increments through
    > > zero.
    > >
    > > However, some negative numbers are used to return error codes.
    > > Hence, there's a period of time when sys_times() returns values
    > > which are indistinguishable from error codes shortly after boot.
    >
    > What a strange system call.
    >
    > > This probably only affects 32-bit architectures. However, one
    > > wonders whether sys_times() needs force_successful_syscall_return().
    >
    > I'd say so, yes. But lots of architectures seem to have a no-op there.

    As I mentioned below, these other architectures need glibc to be fixed.

    > > Also, it appears that glibc does indeed interpret the return value
    > > from sys_times in the way I describe above on at least ARM and x86.
    > > Other architectures may be similarly affected. Hopefully the ARM
    > > glibc folk will raise a cross-architecture bug in glibc for this. 

    -- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core
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