Re: nanosleep interrupted by ignored signals

From: George Anzinger
Date: Thu Nov 25 2004 - 00:49:12 EST


Matt Mackall wrote:
Take the following trivial program:

#include <unistd.h>

int main(void)
{
sleep(10);
return 0;
}

Run it in an xterm. Note that resizing the xterm has no effect on the
process. Now do the same with strace:

brk(0x80495bc) = 0x80495bc
brk(0x804a000) = 0x804a000
rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
nanosleep({10, 0}, 0xbffff548) = -1 EINTR (Interrupted system
call)
--- SIGWINCH (Window changed) ---
_exit(0) = ?

In short, nanosleep is getting interrupted by signals that are
supposedly ignored when a process is being praced. This appears to be
a long-standing bug.

It also appears to be a long-known bug. I found some old discussion of this
problem here but no sign of any resolution:

http://www.ussg.iu.edu/hypermail/linux/kernel/0108.1/1448.html

What's the current thinking on this?

This should have been resolved with the 2.6 changes, in particular, the restart code. What kernel are you using?


--
George Anzinger george@xxxxxxxxxx
High-res-timers: http://sourceforge.net/projects/high-res-timers/

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