linux-kernel - [bug] Re: [PATCH] - Fix stack overflow for large values of MAX

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 24 Jun 2008 12:24:01 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Jack Steiner <steiner@....com>
Cc:	tglx@...utronix.de, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, Mike Travis <travis@....com>
Subject: [bug] Re: [PATCH] - Fix stack overflow for large values of
	MAX_APICS


* Ingo Molnar <mingo@...e.hu> wrote:

> * Jack Steiner <steiner@....com> wrote:
> 
> > physid_mask_of_physid() causes a huge stack (12k) to be created if 
> > the number of APICS is large. Replace physid_mask_of_physid() with a 
> > new function that does not create large stacks. This is a problem 
> > only on large x86_64 systems.
> 
> this indeed fixes the crash i reported here:
> 
>    http://lkml.org/lkml/2008/6/19/98
> 
> so i've added both this and the MAXAPICS patch to tip/x86/uv, and will 
> test it some more. Lets hope it goes all well this time :-)

-tip auto-testing found a new boot failure on x86 which happens if 
NR_CPUS is changed from 8 to 4096. The hang goes like this:

 Linux version 2.6.26-rc7-tip (mingo@...ne) (gcc version 4.2.3) #10233 SMP
 Tue Jun 24 12:13:46 CEST 2008
 [...]
 initcall init_mnt_writers+0x0/0x8c returned 0 after 0 msecs
 calling  eventpoll_init+0x0/0x9a
 initcall eventpoll_init+0x0/0x9a returned 0 after 0 msecs
 calling  anon_inode_init+0x0/0x11a
 initcall anon_inode_init+0x0/0x11a returned 0 after 0 msecs
 calling  pcie_aspm_init+0x0/0x27
 initcall pcie_aspm_init+0x0/0x27 returned 0 after 0 msecs
 calling  acpi_event_init+0x0/0x57
 [... hard hang ...]

on a good bootup, it would continue like this:

 initcall acpi_event_init+0x0/0x57 returned 0 after 38 msecs
 calling  pnp_system_init+0x0/0x17
 [...]

the config, full bootlog and reproducer bzImage is at:

  http://redhat.com/~mingo/misc/config-Tue_Jun_24_07_44_17_CEST_2008.bad
  http://redhat.com/~mingo/misc/log-Tue_Jun_24_07_44_17_CEST_2008.bad
  http://redhat.com/~mingo/misc/bzImage-Tue_Jun_24_07_44_17_CEST_2008.bad

changing CONFIG_NR_CPUS from 4096 to 8 causes the system to boot up 
fine.

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/