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From: Baoquan He <bhe@redhat.com>
To: Qian Cai <cai@lca.pw>
Cc: linux-nvdimm <linux-nvdimm@lists.01.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	kasan-dev@googlegroups.com, Linux MM <linux-mm@kvack.org>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: devm_memremap_pages() triggers a kasan_add_zero_shadow() warning
Date: Thu, 22 Aug 2019 09:31:00 +0800	[thread overview]
Message-ID: <20190822013100.GC2588@MiWiFi-R3L-srv> (raw)
In-Reply-To: <1566421927.5576.3.camel@lca.pw>

On 08/21/19 at 05:12pm, Qian Cai wrote:
> > > Does disabling CONFIG_RANDOMIZE_BASE help? Maybe that workaround has
> > > regressed. Effectively we need to find what is causing the kernel to
> > > sometimes be placed in the middle of a custom reserved memmap= range.
> > 
> > Yes, disabling KASLR works good so far. Assuming the workaround, i.e.,
> > f28442497b5c
> > (“x86/boot: Fix KASLR and memmap= collision”) is correct.
> > 
> > The only other commit that might regress it from my research so far is,
> > 
> > d52e7d5a952c ("x86/KASLR: Parse all 'memmap=' boot option entries”)
> > 
> 
> It turns out that the origin commit f28442497b5c (“x86/boot: Fix KASLR and
> memmap= collision”) has a bug that is unable to handle "memmap=" in
> CONFIG_CMDLINE instead of a parameter in bootloader because when it (as well as
> the commit d52e7d5a952c) calls get_cmd_line_ptr() in order to run
> mem_avoid_memmap(), "boot_params" has no knowledge of CONFIG_CMDLINE. Only later
> in setup_arch(), the kernel will deal with parameters over there.

Yes, we didn't consider CONFIG_CMDLINE during boot compressing stage. It
should be a generic issue since other parameters from CONFIG_CMDLINE could
be ignored too, not only KASLR handling. Would you like to cast a patch
to fix it? Or I can fix it later, maybe next week.

Thanks
Baoquan
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Linux-nvdimm@lists.01.org
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WARNING: multiple messages have this Message-ID (diff)
From: Baoquan He <bhe@redhat.com>
To: Qian Cai <cai@lca.pw>
Cc: Dan Williams <dan.j.williams@intel.com>,
	Linux MM <linux-mm@kvack.org>,
	linux-nvdimm <linux-nvdimm@lists.01.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	kasan-dev@googlegroups.com, Dave Jiang <dave.jiang@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: devm_memremap_pages() triggers a kasan_add_zero_shadow() warning
Date: Thu, 22 Aug 2019 09:31:00 +0800	[thread overview]
Message-ID: <20190822013100.GC2588@MiWiFi-R3L-srv> (raw)
In-Reply-To: <1566421927.5576.3.camel@lca.pw>

On 08/21/19 at 05:12pm, Qian Cai wrote:
> > > Does disabling CONFIG_RANDOMIZE_BASE help? Maybe that workaround has
> > > regressed. Effectively we need to find what is causing the kernel to
> > > sometimes be placed in the middle of a custom reserved memmap= range.
> > 
> > Yes, disabling KASLR works good so far. Assuming the workaround, i.e.,
> > f28442497b5c
> > (“x86/boot: Fix KASLR and memmap= collision”) is correct.
> > 
> > The only other commit that might regress it from my research so far is,
> > 
> > d52e7d5a952c ("x86/KASLR: Parse all 'memmap=' boot option entries”)
> > 
> 
> It turns out that the origin commit f28442497b5c (“x86/boot: Fix KASLR and
> memmap= collision”) has a bug that is unable to handle "memmap=" in
> CONFIG_CMDLINE instead of a parameter in bootloader because when it (as well as
> the commit d52e7d5a952c) calls get_cmd_line_ptr() in order to run
> mem_avoid_memmap(), "boot_params" has no knowledge of CONFIG_CMDLINE. Only later
> in setup_arch(), the kernel will deal with parameters over there.

Yes, we didn't consider CONFIG_CMDLINE during boot compressing stage. It
should be a generic issue since other parameters from CONFIG_CMDLINE could
be ignored too, not only KASLR handling. Would you like to cast a patch
to fix it? Or I can fix it later, maybe next week.

Thanks
Baoquan


  reply	other threads:[~2019-08-22  1:32 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-16 21:35 devm_memremap_pages() triggers a kasan_add_zero_shadow() warning Qian Cai
2019-08-16 21:35 ` Qian Cai
2019-08-16 21:48 ` Dan Williams
2019-08-16 21:48   ` Dan Williams
2019-08-17  3:34   ` Qian Cai
2019-08-17  3:57     ` Dan Williams
2019-08-17  3:57       ` Dan Williams
2019-08-17 11:12       ` Qian Cai
2019-08-17 11:12         ` Qian Cai
2019-08-17 16:59         ` Dan Williams
2019-08-17 16:59           ` Dan Williams
2019-08-18  3:25           ` Qian Cai
2019-08-21 21:12             ` Qian Cai
2019-08-21 21:12               ` Qian Cai
2019-08-22  1:31               ` Baoquan He [this message]
2019-08-22  1:31                 ` Baoquan He
2019-08-22  1:52                 ` Qian Cai

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