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From: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
To: Qian Cai <cai@lca.pw>, Michael Ellerman <mpe@ellerman.id.au>,
	Russell Currey <ruscur@russell.cc>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Nicholas Piggin <npiggin@gmail.com>
Subject: Re: POWER9 crash due to STRICT_KERNEL_RWX (WAS: Re: Linux-next POWER9 NULL pointer NIP...)
Date: Fri, 17 Apr 2020 12:31:20 +0530	[thread overview]
Message-ID: <1587106774.1oa2whm69m.naveen@linux.ibm.com> (raw)
In-Reply-To: <69F0448F-CA5B-497D-B8AF-2848175B9477@lca.pw>

Hi Qian,

Qian Cai wrote:
> OK, reverted the commit,
> 
> c55d7b5e6426 (“powerpc: Remove STRICT_KERNEL_RWX incompatibility with RELOCATABLE”)
> 
> or set STRICT_KERNEL_RWX=n fixed the crash below and also mentioned in this thread,
> 
> https://lore.kernel.org/lkml/15AC5B0E-A221-4B8C-9039-FA96B8EF7C88@lca.pw/

Do you see any errors logged in dmesg when you see the crash?  
STRICT_KERNEL_RWX changes how patch_instruction() works, so it would be 
interesting to see if there are any ftrace-related errors thrown before 
the crash.


- Naveen


WARNING: multiple messages have this Message-ID (diff)
From: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
To: Qian Cai <cai@lca.pw>, Michael Ellerman <mpe@ellerman.id.au>,
	Russell Currey <ruscur@russell.cc>
Cc: LKML <linux-kernel@vger.kernel.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	Nicholas Piggin <npiggin@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: POWER9 crash due to STRICT_KERNEL_RWX (WAS: Re: Linux-next POWER9 NULL pointer NIP...)
Date: Fri, 17 Apr 2020 12:31:20 +0530	[thread overview]
Message-ID: <1587106774.1oa2whm69m.naveen@linux.ibm.com> (raw)
In-Reply-To: <69F0448F-CA5B-497D-B8AF-2848175B9477@lca.pw>

Hi Qian,

Qian Cai wrote:
> OK, reverted the commit,
> 
> c55d7b5e6426 (“powerpc: Remove STRICT_KERNEL_RWX incompatibility with RELOCATABLE”)
> 
> or set STRICT_KERNEL_RWX=n fixed the crash below and also mentioned in this thread,
> 
> https://lore.kernel.org/lkml/15AC5B0E-A221-4B8C-9039-FA96B8EF7C88@lca.pw/

Do you see any errors logged in dmesg when you see the crash?  
STRICT_KERNEL_RWX changes how patch_instruction() works, so it would be 
interesting to see if there are any ftrace-related errors thrown before 
the crash.


- Naveen


  parent reply	other threads:[~2020-04-17  7:03 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-07  2:28 Linux-next POWER9 NULL pointer NIP since 1st Apr Qian Cai
2020-04-07 12:42 ` Michael Ellerman
2020-04-07 13:01   ` Qian Cai
2020-04-07 13:01     ` Qian Cai
2020-04-07 13:30     ` Steven Rostedt
2020-04-07 13:30       ` Steven Rostedt
2020-04-09  3:40       ` Qian Cai
2020-04-09  3:40         ` Qian Cai
2020-04-09 10:06       ` Qian Cai
2020-04-09 10:06         ` Qian Cai
2020-04-09 14:14         ` Steven Rostedt
2020-04-09 14:14           ` Steven Rostedt
2020-04-10 19:20           ` Qian Cai
2020-04-10 19:20             ` Qian Cai
2020-04-15 15:57             ` Qian Cai
2020-04-15 15:57               ` Qian Cai
2020-04-17  1:19               ` POWER9 crash due to STRICT_KERNEL_RWX (WAS: Re: Linux-next POWER9 NULL pointer NIP...) Qian Cai
2020-04-17  1:19                 ` Qian Cai
2020-04-17  2:17                 ` Steven Rostedt
2020-04-17  2:17                   ` Steven Rostedt
2020-04-17  2:27                   ` Russell Currey
2020-04-17  2:27                     ` Russell Currey
2020-04-17 11:45                   ` Michael Ellerman
2020-04-17 11:45                     ` Michael Ellerman
2020-04-17  7:01                 ` Naveen N. Rao [this message]
2020-04-17  7:01                   ` Naveen N. Rao
2020-04-17 11:49                   ` Michael Ellerman
2020-04-17 11:49                     ` Michael Ellerman
2020-04-17 12:00                   ` Qian Cai
2020-04-17 12:00                     ` Qian Cai
2020-04-17 15:18                     ` Naveen N. Rao
2020-04-17 15:18                       ` Naveen N. Rao
  -- strict thread matches above, loose matches on Subject: below --
2020-04-17  2:40 Qian Cai
2020-04-17  2:40 ` Qian Cai
2020-04-17  2:46 ` Russell Currey
2020-04-17  2:46   ` Russell Currey
2020-04-17  3:16   ` Qian Cai
2020-04-17  3:16     ` Qian Cai
2020-04-17 11:49   ` Qian Cai
2020-04-17 11:49     ` Qian Cai

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