linux-kernel - Re: oprofile BUG() in current kernel.

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <48296C96.8060000@cosmosbay.com>
Date:	Tue, 13 May 2008 12:25:26 +0200
From:	Eric Dumazet <dada1@...mosbay.com>
To:	Gianni Tedesco <gxt@...nott.ac.uk>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	arges@...ux.vnet.ibm.com, Maynard Johnson <maynardj@...ibm.com>,
	Vegard Nossum <vegard.nossum@...il.com>,
	linux-kernel@...r.kernel.org, oprofile-list@...ts.sourceforge.net,
	Mike Travis <travis@....com>
Subject: Re: oprofile BUG() in current kernel.

Gianni Tedesco a écrit :
>
>
> Nope, exact same bad paging request in kernel mode... probably the bug
> is something deep in oprofile then?
>   
Hum... Are you using oprofile as a module or statically included in kernel ?

Current module loader only allocates percpu room by examining 
".data.percpu" section and should be augmented to also look at 
".data.percpu.shared_aligned"
Or, change DEFINE_PER_CPU_SHARED_ALIGNED() for modules (to use 
".data.percpu" only)

Anyway, with the per_cpu conversion of cpu_buffer, we dont need to 
request cache_line alignment anymore

[PATCH] oprofile: Dont request cache line alignment for cpu_buffer

Alignment was previously requested because cpu_buffer was an [NR_CPUS] 
array, to avoid cache line sharing between CPUS.

After commit 608dfddd845da5ab6accef70154c8910529699f7 ( 
oprofile: change cpu_buffer from array to per_cpu variable ),
we dont need to force an alignement anymore since cpu_buffer sits in 
per_cpu zone.

Signed-off-by: Eric Dumazet <dada1@...mosbay.com>



View attachment "oprofile.patch" of type "text/plain" (823 bytes)