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From: Johannes Berg <johannes@sipsolutions.net>
To: "Sang, Oliver" <oliver.sang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Peter Oberparleiter <oberpar@linux.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"lkp@lists.01.org" <lkp@lists.01.org>, lkp <lkp@intel.com>
Subject: Re: [gcov]  1391efa952: BUG:KASAN:slab-out-of-bounds_in_gcov_info_add
Date: Thu, 25 Nov 2021 16:45:07 +0100	[thread overview]
Message-ID: <a5274ba1922d5eaf9568886191e0a05bdfc55506.camel@sipsolutions.net> (raw)
In-Reply-To: <20211125142622.GD3109@xsang-OptiPlex-9020>

On Thu, 2021-11-25 at 14:26 +0000, Sang, Oliver wrote:
> 
> Greeting,
> 
> FYI, we noticed the following commit (built with clang-14):
> 
> commit: 1391efa952e8b22088f8626fc63ade26767b92d6 ("gcov: use kvmalloc()")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
> 
> in testcase: boot
> 
> on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
> 
> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
> 

I don't think it actually *caused* the issue, but who knows? To me it
rather looks like it exposed an issue, which wasn't noticed before
because vmalloc() always allocates a page anyway? Assuming KASAN doesn't
track vmalloc() allocations more granular than their actual page-aligned
memory size (though perhaps it should?)

In any case, reviewing my commit again I see nothing wrong there, and I
don't understand the code/clang well enough to see what might be the
issue.

johannes

  reply	other threads:[~2021-11-25 15:53 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-25 14:26 [gcov] 1391efa952: BUG:KASAN:slab-out-of-bounds_in_gcov_info_add kernel test robot
2021-11-25 15:45 ` Johannes Berg [this message]
2021-11-25 17:48   ` Linus Torvalds
2021-11-25 20:42     ` Johannes Berg

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