From mboxrd@z Thu Jan 1 00:00:00 1970 From: Petr Tesarik Date: Tue, 27 May 2008 06:25:15 +0000 Subject: Re: [RFC PATCH] set TASK_TRACED before arch_ptrace code to fix a Message-Id: <1211869515.29836.2.camel@elijah.suse.cz> List-Id: References: <3877989d0805211947i54bacc7cv619541e9b40824fb@mail.gmail.com> <3877989d0805220624i259a9d1j708795c65c636ca0@mail.gmail.com> <20080522203428.835D626FA24@magilla.localdomain> <3877989d0805222042p176da844k384ea512b1cfb0da@mail.gmail.com> <20080523041940.39E8726FA24@magilla.localdomain> <3877989d0805222224n77ce36b6wdf15c4bab330a0f8@mail.gmail.com> <20080526001527.81E1126FA9E@magilla.localdomain> <3877989d0805251830w70f19e4cu46fbc32148217749@mail.gmail.com> <3877989d0805262031i29db16bcjfa31652afc746b49@mail.gmail.com> <20080527040454.053C526FA9E@magilla.localdomain> <3877989d0805262249yab130cbyfc5f5e54065cec5c@mail.gmail.com> <20080527061209.9A24426FAA6@magilla.localdomain> In-Reply-To: <20080527061209.9A24426FAA6@magilla.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: Roland McGrath Cc: Luming Yu , LKML , linux-ia64@vger.kernel.org On Mon, 2008-05-26 at 23:12 -0700, Roland McGrath wrote: > > [] skip_rbs_switch+0xe0/0x110 > > sp=E000000141c9fe30 bsp=E000000141c90cf8 > > [] __kernel_syscall_via_break+0x0/0x20 > > sp=E000000141ca0000 bsp=E000000141c90cf8 Indeed, there seems to be a large hole here. So, this is either a bug in the unwinder, or a bug in the RBS synchronization, which causes corruption. My test machine currently needs some work to run 2.6.25 again, but I'll try your test case as soon as I re-install it later this week. Cheers, Petr Tesarik > > [] ptrace_stop+0xa0/0x3e0 > > sp=E00000014716fdb0 bsp=E000000147160ca8 > > [] ptrace_notify+0x150/0x1c0 > > sp=E00000014716fdb0 bsp=E000000147160c88 >=20 > If this is a backtrace of a single thread on the same kernel stack, it has > a stack depth of over 84MB. You still need to follow the path inside > ia64_ptrace_stop() to see how any of this is possible. >=20 >=20 > Thanks, > Roland