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Date: Thu, 19 Jul 2012 22:11:17 +0400
From: Vasily Kulikov <segoon@...nwall.com>
To: owl-dev@...ts.openwall.com
Subject: Re: strace with restart_syscall output (was: status of
 2.6.32-based kernel)

On Thu, Jul 19, 2012 at 22:04 +0400, Dmitry V. Levin wrote:
> On Thu, Jul 19, 2012 at 08:43:07PM +0400, Vasily Kulikov wrote:
> > On Thu, Jul 19, 2012 at 20:22 +0400, Dmitry V. Levin wrote:
> > > On Thu, Jul 19, 2012 at 08:13:05PM +0400, Vasily Kulikov wrote:
> > > [...]
> > > > I've tried some tools a bit like modprobe, ip, nmap, ping, brctl --
> > > > everything works, except strace.  It shows the same line for every
> > > > syscall:
> > > > 
> > > > restart_syscall(<... resuming interrupted call ...>) = 12
> > > > restart_syscall(<... resuming interrupted call ...>) = 0
> > > > restart_syscall(<... resuming interrupted call ...>) = 0
> > > > ...
> > > 
> > > Is it x86 or x86-64?  __NR_restart_syscall is 0 on x86.
> > 
> > It is x86
> 
> Then most likely it fails to fetch syscall numbers, and if it is the case,
> then it also fails to recognize the failure.
> Let's have a look at "strace -d /bin/true" output, it may give a clue.

root@...alhost:~ # strace -d /bin/true
ptrace_setoptions = 0x11
new tcb for pid 1302, active tcbs:1
 [wait(0x137f) = 1302] WIFSTOPPED,sig=SIGSTOP
pid 1302 has TCB_STARTUP, initializing it
setting opts 11 on pid 1302
ignored SIGSTOP on pid 1302
 [wait(0x857f) = 1302] WIFSTOPPED,sig=133
restart_syscall(<... resuming interrupted call ...> [wait(0x4057f) = 1302] WIFSTOPPED,sig=SIGTRAP,PTRACE_EVENT_EXEC
 [wait(0x857f) = 1302] WIFSTOPPED,sig=133
) = 0
 [wait(0x857f) = 1302] WIFSTOPPED,sig=133
restart_syscall(<... resuming interrupted call ...> [wait(0x0000) = 1302] WIFEXITED,exitcode=0
 <unfinished ...>
+++ exited with 0 +++
dropped tcb for pid 1302, 0 remain
root@...alhost:~ #

-- 
Vasily

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