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From: Arnd Bergmann <arnd@kernel.org>
To: Martin Sebor <msebor@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Martin Sebor <msebor@gcc.gnu.org>, Ning Sun <ning.sun@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	Kalle Valo <kvalo@codeaurora.org>,
	Simon Kelley <simon@thekelleys.org.uk>,
	James Smart <james.smart@broadcom.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	Anders Larsen <al@alarsen.net>, Tejun Heo <tj@kernel.org>,
	Serge Hallyn <serge@hallyn.com>, Imre Deak <imre.deak@intel.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	tboot-devel@lists.sourceforge.net,
	Intel Graphics <intel-gfx@lists.freedesktop.org>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	ath11k@lists.infradead.org,
	linux-wireless <linux-wireless@vger.kernel.org>,
	Networking <netdev@vger.kernel.org>,
	linux-scsi <linux-scsi@vger.kernel.org>,
	Cgroups <cgroups@vger.kernel.org>,
	LSM List <linux-security-module@vger.kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	Will Deacon <will@kernel.org>
Subject: Re: [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning
Date: Mon, 22 Mar 2021 23:49:53 +0100	[thread overview]
Message-ID: <CAK8P3a0JW0AqQmHXaveD8za1np+W=Q3D4PuHnYKRd8UJqiwhsw@mail.gmail.com> (raw)
In-Reply-To: <b944a853-0e4b-b767-0175-cc2c1edba759@gmail.com>

On Mon, Mar 22, 2021 at 11:09 PM Martin Sebor <msebor@gmail.com> wrote:
> On 3/22/21 2:29 PM, Ingo Molnar wrote:
> > * Arnd Bergmann <arnd@kernel.org> wrote:
> >
> > I.e. the real workaround might be to turn off the -Wstringop-overread-warning,
> > until GCC-11 gets fixed?
>
> In GCC 10 -Wstringop-overread is a subset of -Wstringop-overflow.
> GCC 11 breaks it out as a separate warning to make it easier to
> control.  Both warnings have caught some real bugs but they both
> have a nonzero rate of false positives.  Other than bug reports
> we don't have enough data to say what their S/N ratio might be
> but my sense is that it's fairly high in general.
>
>    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=wstringop-overread
>    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=wstringop-overflow

Unfortunately, stringop-overflow is one of the warnings that is
completely disabled in the kernel at the moment, rather than
enabled at one of the user-selectable higher warning levels.

I have a patch series to change that and to pull some of these
into the lower W=1 or W=2 levels or even enable them by default.

To do this though, I first need to ensure that the actual output
is empty for the normal builds. I added -Wstringop-overflow to
the list of warnings I wanted to address because it is a new
warning and only has a dozen or so occurrences throughout the
kernel.

> In GCC 11, all access warnings expect objects to be either declared
> or allocated.  Pointers with constant values are taken to point to
> nothing valid (as Arnd mentioned above, this is to detect invalid
> accesses to members of structs at address zero).
>
> One possible solution to the known address problem is to extend GCC
> attributes address and io that pin an object to a hardwired address
> to all targets (at the moment they're supported on just one or two
> targets).  I'm not sure this can still happen before GCC 11 releases
> sometime in April or May.
>
> Until then, another workaround is to convert the fixed address to
> a volatile pointer before using it for the access, along the lines
> below.  It should have only a negligible effect on efficiency.
>
> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
> index 4c09ba110204..76326b906010 100644
> --- a/arch/x86/kernel/tboot.c
> +++ b/arch/x86/kernel/tboot.c
> @@ -67,7 +67,9 @@ void __init tboot_probe(void)
>          /* Map and check for tboot UUID. */
>          set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
>          tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
> -       if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
> +       if (memcmp(&tboot_uuid,
> +                  (*(struct tboot* volatile *)(&tboot))->uuid,
> +                  sizeof(tboot->uuid))) {
>                  pr_warn("tboot at 0x%llx is invalid\n",

I think a stray 'volatile' would raise too many red flags here, but
I checked that the RELOC_HIDE() macro has the same effect, e.g.

@@ -66,7 +67,8 @@ void __init tboot_probe(void)

        /* Map and check for tboot UUID. */
        set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
-       tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
+       /* RELOC_HIDE to prevent gcc warnings about NULL pointer */
+       tboot = RELOC_HIDE(NULL, fix_to_virt(FIX_TBOOT_BASE));
        if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
                pr_warn("tboot at 0x%llx is invalid\n", boot_params.tboot_addr);
                tboot = NULL;

     Arnd

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@kernel.org>
To: Martin Sebor <msebor@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>,
	 Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Martin Sebor <msebor@gcc.gnu.org>,  Ning Sun <ning.sun@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,  Borislav Petkov <bp@alien8.de>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	 Kalle Valo <kvalo@codeaurora.org>,
	Simon Kelley <simon@thekelleys.org.uk>,
	 James Smart <james.smart@broadcom.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	 Anders Larsen <al@alarsen.net>, Tejun Heo <tj@kernel.org>,
	Serge Hallyn <serge@hallyn.com>, Imre Deak <imre.deak@intel.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	 tboot-devel@lists.sourceforge.net,
	 Intel Graphics <intel-gfx@lists.freedesktop.org>,
	 dri-devel <dri-devel@lists.freedesktop.org>,
	ath11k@lists.infradead.org,
	 linux-wireless <linux-wireless@vger.kernel.org>,
	Networking <netdev@vger.kernel.org>,
	 linux-scsi <linux-scsi@vger.kernel.org>,
	Cgroups <cgroups@vger.kernel.org>,
	 LSM List <linux-security-module@vger.kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	 Andrew Morton <akpm@linux-foundation.org>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	Will Deacon <will@kernel.org>
Subject: Re: [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning
Date: Mon, 22 Mar 2021 23:49:53 +0100	[thread overview]
Message-ID: <CAK8P3a0JW0AqQmHXaveD8za1np+W=Q3D4PuHnYKRd8UJqiwhsw@mail.gmail.com> (raw)
In-Reply-To: <b944a853-0e4b-b767-0175-cc2c1edba759@gmail.com>

On Mon, Mar 22, 2021 at 11:09 PM Martin Sebor <msebor@gmail.com> wrote:
> On 3/22/21 2:29 PM, Ingo Molnar wrote:
> > * Arnd Bergmann <arnd@kernel.org> wrote:
> >
> > I.e. the real workaround might be to turn off the -Wstringop-overread-warning,
> > until GCC-11 gets fixed?
>
> In GCC 10 -Wstringop-overread is a subset of -Wstringop-overflow.
> GCC 11 breaks it out as a separate warning to make it easier to
> control.  Both warnings have caught some real bugs but they both
> have a nonzero rate of false positives.  Other than bug reports
> we don't have enough data to say what their S/N ratio might be
> but my sense is that it's fairly high in general.
>
>    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=wstringop-overread
>    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=wstringop-overflow

Unfortunately, stringop-overflow is one of the warnings that is
completely disabled in the kernel at the moment, rather than
enabled at one of the user-selectable higher warning levels.

I have a patch series to change that and to pull some of these
into the lower W=1 or W=2 levels or even enable them by default.

To do this though, I first need to ensure that the actual output
is empty for the normal builds. I added -Wstringop-overflow to
the list of warnings I wanted to address because it is a new
warning and only has a dozen or so occurrences throughout the
kernel.

> In GCC 11, all access warnings expect objects to be either declared
> or allocated.  Pointers with constant values are taken to point to
> nothing valid (as Arnd mentioned above, this is to detect invalid
> accesses to members of structs at address zero).
>
> One possible solution to the known address problem is to extend GCC
> attributes address and io that pin an object to a hardwired address
> to all targets (at the moment they're supported on just one or two
> targets).  I'm not sure this can still happen before GCC 11 releases
> sometime in April or May.
>
> Until then, another workaround is to convert the fixed address to
> a volatile pointer before using it for the access, along the lines
> below.  It should have only a negligible effect on efficiency.
>
> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
> index 4c09ba110204..76326b906010 100644
> --- a/arch/x86/kernel/tboot.c
> +++ b/arch/x86/kernel/tboot.c
> @@ -67,7 +67,9 @@ void __init tboot_probe(void)
>          /* Map and check for tboot UUID. */
>          set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
>          tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
> -       if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
> +       if (memcmp(&tboot_uuid,
> +                  (*(struct tboot* volatile *)(&tboot))->uuid,
> +                  sizeof(tboot->uuid))) {
>                  pr_warn("tboot at 0x%llx is invalid\n",

I think a stray 'volatile' would raise too many red flags here, but
I checked that the RELOC_HIDE() macro has the same effect, e.g.

@@ -66,7 +67,8 @@ void __init tboot_probe(void)

        /* Map and check for tboot UUID. */
        set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
-       tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
+       /* RELOC_HIDE to prevent gcc warnings about NULL pointer */
+       tboot = RELOC_HIDE(NULL, fix_to_virt(FIX_TBOOT_BASE));
        if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
                pr_warn("tboot at 0x%llx is invalid\n", boot_params.tboot_addr);
                tboot = NULL;

     Arnd

-- 
ath11k mailing list
ath11k@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/ath11k

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@kernel.org>
To: Martin Sebor <msebor@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>,
	 Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Martin Sebor <msebor@gcc.gnu.org>,  Ning Sun <ning.sun@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,  Borislav Petkov <bp@alien8.de>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	 Kalle Valo <kvalo@codeaurora.org>,
	Simon Kelley <simon@thekelleys.org.uk>,
	 James Smart <james.smart@broadcom.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	 Anders Larsen <al@alarsen.net>, Tejun Heo <tj@kernel.org>,
	Serge Hallyn <serge@hallyn.com>, Imre Deak <imre.deak@intel.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	 tboot-devel@lists.sourceforge.net,
	 Intel Graphics <intel-gfx@lists.freedesktop.org>,
	 dri-devel <dri-devel@lists.freedesktop.org>,
	ath11k@lists.infradead.org,
	 linux-wireless <linux-wireless@vger.kernel.org>,
	Networking <netdev@vger.kernel.org>,
	 linux-scsi <linux-scsi@vger.kernel.org>,
	Cgroups <cgroups@vger.kernel.org>,
	 LSM List <linux-security-module@vger.kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	 Andrew Morton <akpm@linux-foundation.org>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	Will Deacon <will@kernel.org>
Subject: Re: [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning
Date: Mon, 22 Mar 2021 23:49:53 +0100	[thread overview]
Message-ID: <CAK8P3a0JW0AqQmHXaveD8za1np+W=Q3D4PuHnYKRd8UJqiwhsw@mail.gmail.com> (raw)
In-Reply-To: <b944a853-0e4b-b767-0175-cc2c1edba759@gmail.com>

On Mon, Mar 22, 2021 at 11:09 PM Martin Sebor <msebor@gmail.com> wrote:
> On 3/22/21 2:29 PM, Ingo Molnar wrote:
> > * Arnd Bergmann <arnd@kernel.org> wrote:
> >
> > I.e. the real workaround might be to turn off the -Wstringop-overread-warning,
> > until GCC-11 gets fixed?
>
> In GCC 10 -Wstringop-overread is a subset of -Wstringop-overflow.
> GCC 11 breaks it out as a separate warning to make it easier to
> control.  Both warnings have caught some real bugs but they both
> have a nonzero rate of false positives.  Other than bug reports
> we don't have enough data to say what their S/N ratio might be
> but my sense is that it's fairly high in general.
>
>    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=wstringop-overread
>    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=wstringop-overflow

Unfortunately, stringop-overflow is one of the warnings that is
completely disabled in the kernel at the moment, rather than
enabled at one of the user-selectable higher warning levels.

I have a patch series to change that and to pull some of these
into the lower W=1 or W=2 levels or even enable them by default.

To do this though, I first need to ensure that the actual output
is empty for the normal builds. I added -Wstringop-overflow to
the list of warnings I wanted to address because it is a new
warning and only has a dozen or so occurrences throughout the
kernel.

> In GCC 11, all access warnings expect objects to be either declared
> or allocated.  Pointers with constant values are taken to point to
> nothing valid (as Arnd mentioned above, this is to detect invalid
> accesses to members of structs at address zero).
>
> One possible solution to the known address problem is to extend GCC
> attributes address and io that pin an object to a hardwired address
> to all targets (at the moment they're supported on just one or two
> targets).  I'm not sure this can still happen before GCC 11 releases
> sometime in April or May.
>
> Until then, another workaround is to convert the fixed address to
> a volatile pointer before using it for the access, along the lines
> below.  It should have only a negligible effect on efficiency.
>
> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
> index 4c09ba110204..76326b906010 100644
> --- a/arch/x86/kernel/tboot.c
> +++ b/arch/x86/kernel/tboot.c
> @@ -67,7 +67,9 @@ void __init tboot_probe(void)
>          /* Map and check for tboot UUID. */
>          set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
>          tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
> -       if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
> +       if (memcmp(&tboot_uuid,
> +                  (*(struct tboot* volatile *)(&tboot))->uuid,
> +                  sizeof(tboot->uuid))) {
>                  pr_warn("tboot at 0x%llx is invalid\n",

I think a stray 'volatile' would raise too many red flags here, but
I checked that the RELOC_HIDE() macro has the same effect, e.g.

@@ -66,7 +67,8 @@ void __init tboot_probe(void)

        /* Map and check for tboot UUID. */
        set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
-       tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
+       /* RELOC_HIDE to prevent gcc warnings about NULL pointer */
+       tboot = RELOC_HIDE(NULL, fix_to_virt(FIX_TBOOT_BASE));
        if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
                pr_warn("tboot at 0x%llx is invalid\n", boot_params.tboot_addr);
                tboot = NULL;

     Arnd

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@kernel.org>
To: Martin Sebor <msebor@gmail.com>
Cc: dri-devel <dri-devel@lists.freedesktop.org>,
	"H. Peter Anvin" <hpa@zytor.com>, Will Deacon <will@kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	linux-scsi <linux-scsi@vger.kernel.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	James Smart <james.smart@broadcom.com>,
	tboot-devel@lists.sourceforge.net, Ingo Molnar <mingo@redhat.com>,
	Kalle Valo <kvalo@codeaurora.org>,
	ath11k@lists.infradead.org, Serge Hallyn <serge@hallyn.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	Ning Sun <ning.sun@intel.com>, Anders Larsen <al@alarsen.net>,
	Borislav Petkov <bp@alien8.de>, Cgroups <cgroups@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Martin Sebor <msebor@gcc.gnu.org>,
	Networking <netdev@vger.kernel.org>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	LSM List <linux-security-module@vger.kernel.org>,
	Tejun Heo <tj@kernel.org>, Simon Kelley <simon@thekelleys.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Intel Graphics <intel-gfx@lists.freedesktop.org>,
	Lu Baolu <baolu.lu@linux.intel.com>
Subject: Re: [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning
Date: Mon, 22 Mar 2021 23:49:53 +0100	[thread overview]
Message-ID: <CAK8P3a0JW0AqQmHXaveD8za1np+W=Q3D4PuHnYKRd8UJqiwhsw@mail.gmail.com> (raw)
In-Reply-To: <b944a853-0e4b-b767-0175-cc2c1edba759@gmail.com>

On Mon, Mar 22, 2021 at 11:09 PM Martin Sebor <msebor@gmail.com> wrote:
> On 3/22/21 2:29 PM, Ingo Molnar wrote:
> > * Arnd Bergmann <arnd@kernel.org> wrote:
> >
> > I.e. the real workaround might be to turn off the -Wstringop-overread-warning,
> > until GCC-11 gets fixed?
>
> In GCC 10 -Wstringop-overread is a subset of -Wstringop-overflow.
> GCC 11 breaks it out as a separate warning to make it easier to
> control.  Both warnings have caught some real bugs but they both
> have a nonzero rate of false positives.  Other than bug reports
> we don't have enough data to say what their S/N ratio might be
> but my sense is that it's fairly high in general.
>
>    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=wstringop-overread
>    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=wstringop-overflow

Unfortunately, stringop-overflow is one of the warnings that is
completely disabled in the kernel at the moment, rather than
enabled at one of the user-selectable higher warning levels.

I have a patch series to change that and to pull some of these
into the lower W=1 or W=2 levels or even enable them by default.

To do this though, I first need to ensure that the actual output
is empty for the normal builds. I added -Wstringop-overflow to
the list of warnings I wanted to address because it is a new
warning and only has a dozen or so occurrences throughout the
kernel.

> In GCC 11, all access warnings expect objects to be either declared
> or allocated.  Pointers with constant values are taken to point to
> nothing valid (as Arnd mentioned above, this is to detect invalid
> accesses to members of structs at address zero).
>
> One possible solution to the known address problem is to extend GCC
> attributes address and io that pin an object to a hardwired address
> to all targets (at the moment they're supported on just one or two
> targets).  I'm not sure this can still happen before GCC 11 releases
> sometime in April or May.
>
> Until then, another workaround is to convert the fixed address to
> a volatile pointer before using it for the access, along the lines
> below.  It should have only a negligible effect on efficiency.
>
> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
> index 4c09ba110204..76326b906010 100644
> --- a/arch/x86/kernel/tboot.c
> +++ b/arch/x86/kernel/tboot.c
> @@ -67,7 +67,9 @@ void __init tboot_probe(void)
>          /* Map and check for tboot UUID. */
>          set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
>          tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
> -       if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
> +       if (memcmp(&tboot_uuid,
> +                  (*(struct tboot* volatile *)(&tboot))->uuid,
> +                  sizeof(tboot->uuid))) {
>                  pr_warn("tboot at 0x%llx is invalid\n",

I think a stray 'volatile' would raise too many red flags here, but
I checked that the RELOC_HIDE() macro has the same effect, e.g.

@@ -66,7 +67,8 @@ void __init tboot_probe(void)

        /* Map and check for tboot UUID. */
        set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
-       tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
+       /* RELOC_HIDE to prevent gcc warnings about NULL pointer */
+       tboot = RELOC_HIDE(NULL, fix_to_virt(FIX_TBOOT_BASE));
        if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
                pr_warn("tboot at 0x%llx is invalid\n", boot_params.tboot_addr);
                tboot = NULL;

     Arnd
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@kernel.org>
To: Martin Sebor <msebor@gmail.com>
Cc: dri-devel <dri-devel@lists.freedesktop.org>,
	"H. Peter Anvin" <hpa@zytor.com>, Will Deacon <will@kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	linux-scsi <linux-scsi@vger.kernel.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	James Smart <james.smart@broadcom.com>,
	tboot-devel@lists.sourceforge.net, Ingo Molnar <mingo@redhat.com>,
	Kalle Valo <kvalo@codeaurora.org>,
	ath11k@lists.infradead.org, Serge Hallyn <serge@hallyn.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	Ning Sun <ning.sun@intel.com>, Anders Larsen <al@alarsen.net>,
	Borislav Petkov <bp@alien8.de>, Cgroups <cgroups@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Martin Sebor <msebor@gcc.gnu.org>,
	Networking <netdev@vger.kernel.org>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	LSM List <linux-security-module@vger.kernel.org>,
	Tejun Heo <tj@kernel.org>, Simon Kelley <simon@thekelleys.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Intel Graphics <intel-gfx@lists.freedesktop.org>,
	Lu Baolu <baolu.lu@linux.intel.com>
Subject: Re: [Intel-gfx] [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning
Date: Mon, 22 Mar 2021 23:49:53 +0100	[thread overview]
Message-ID: <CAK8P3a0JW0AqQmHXaveD8za1np+W=Q3D4PuHnYKRd8UJqiwhsw@mail.gmail.com> (raw)
In-Reply-To: <b944a853-0e4b-b767-0175-cc2c1edba759@gmail.com>

On Mon, Mar 22, 2021 at 11:09 PM Martin Sebor <msebor@gmail.com> wrote:
> On 3/22/21 2:29 PM, Ingo Molnar wrote:
> > * Arnd Bergmann <arnd@kernel.org> wrote:
> >
> > I.e. the real workaround might be to turn off the -Wstringop-overread-warning,
> > until GCC-11 gets fixed?
>
> In GCC 10 -Wstringop-overread is a subset of -Wstringop-overflow.
> GCC 11 breaks it out as a separate warning to make it easier to
> control.  Both warnings have caught some real bugs but they both
> have a nonzero rate of false positives.  Other than bug reports
> we don't have enough data to say what their S/N ratio might be
> but my sense is that it's fairly high in general.
>
>    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=wstringop-overread
>    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=wstringop-overflow

Unfortunately, stringop-overflow is one of the warnings that is
completely disabled in the kernel at the moment, rather than
enabled at one of the user-selectable higher warning levels.

I have a patch series to change that and to pull some of these
into the lower W=1 or W=2 levels or even enable them by default.

To do this though, I first need to ensure that the actual output
is empty for the normal builds. I added -Wstringop-overflow to
the list of warnings I wanted to address because it is a new
warning and only has a dozen or so occurrences throughout the
kernel.

> In GCC 11, all access warnings expect objects to be either declared
> or allocated.  Pointers with constant values are taken to point to
> nothing valid (as Arnd mentioned above, this is to detect invalid
> accesses to members of structs at address zero).
>
> One possible solution to the known address problem is to extend GCC
> attributes address and io that pin an object to a hardwired address
> to all targets (at the moment they're supported on just one or two
> targets).  I'm not sure this can still happen before GCC 11 releases
> sometime in April or May.
>
> Until then, another workaround is to convert the fixed address to
> a volatile pointer before using it for the access, along the lines
> below.  It should have only a negligible effect on efficiency.
>
> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
> index 4c09ba110204..76326b906010 100644
> --- a/arch/x86/kernel/tboot.c
> +++ b/arch/x86/kernel/tboot.c
> @@ -67,7 +67,9 @@ void __init tboot_probe(void)
>          /* Map and check for tboot UUID. */
>          set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
>          tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
> -       if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
> +       if (memcmp(&tboot_uuid,
> +                  (*(struct tboot* volatile *)(&tboot))->uuid,
> +                  sizeof(tboot->uuid))) {
>                  pr_warn("tboot at 0x%llx is invalid\n",

I think a stray 'volatile' would raise too many red flags here, but
I checked that the RELOC_HIDE() macro has the same effect, e.g.

@@ -66,7 +67,8 @@ void __init tboot_probe(void)

        /* Map and check for tboot UUID. */
        set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
-       tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
+       /* RELOC_HIDE to prevent gcc warnings about NULL pointer */
+       tboot = RELOC_HIDE(NULL, fix_to_virt(FIX_TBOOT_BASE));
        if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
                pr_warn("tboot at 0x%llx is invalid\n", boot_params.tboot_addr);
                tboot = NULL;

     Arnd
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WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Martin Sebor <msebor-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Linux Kernel Mailing List
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Martin Sebor <msebor-/MQLu3FmUzdAfugRpC6u6w@public.gmane.org>,
	Ning Sun <ning.sun-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
	Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>,
	the arch/x86 maintainers
	<x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Jani Nikula <jani.nikula-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>,
	Kalle Valo <kvalo-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	Simon Kelley
	<simon-xn1N/tgparsycpQjotevgVpr/1R2p/CL@public.gmane.org>,
	James Smart <james.smart-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>,
	"James E.J. Bottomley"
	<jejb-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>,
	Anders Larsen <al-V9/YLgxv/GvR7s880joybQ@public.gmane.org>,
	Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Serge Hallyn <serge-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org>,
	Imre Deak <imre.deak-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	Linux ARM
	<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
	tboot-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
	Intel Graphics
	<intel-gfx-PD4FTy7X32lNgt0PjOBp9/rsn8yoX9R0@public.gmane.org>
Subject: Re: [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning
Date: Mon, 22 Mar 2021 23:49:53 +0100	[thread overview]
Message-ID: <CAK8P3a0JW0AqQmHXaveD8za1np+W=Q3D4PuHnYKRd8UJqiwhsw@mail.gmail.com> (raw)
In-Reply-To: <b944a853-0e4b-b767-0175-cc2c1edba759-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

On Mon, Mar 22, 2021 at 11:09 PM Martin Sebor <msebor-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On 3/22/21 2:29 PM, Ingo Molnar wrote:
> > * Arnd Bergmann <arnd-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
> >
> > I.e. the real workaround might be to turn off the -Wstringop-overread-warning,
> > until GCC-11 gets fixed?
>
> In GCC 10 -Wstringop-overread is a subset of -Wstringop-overflow.
> GCC 11 breaks it out as a separate warning to make it easier to
> control.  Both warnings have caught some real bugs but they both
> have a nonzero rate of false positives.  Other than bug reports
> we don't have enough data to say what their S/N ratio might be
> but my sense is that it's fairly high in general.
>
>    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=wstringop-overread
>    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=wstringop-overflow

Unfortunately, stringop-overflow is one of the warnings that is
completely disabled in the kernel at the moment, rather than
enabled at one of the user-selectable higher warning levels.

I have a patch series to change that and to pull some of these
into the lower W=1 or W=2 levels or even enable them by default.

To do this though, I first need to ensure that the actual output
is empty for the normal builds. I added -Wstringop-overflow to
the list of warnings I wanted to address because it is a new
warning and only has a dozen or so occurrences throughout the
kernel.

> In GCC 11, all access warnings expect objects to be either declared
> or allocated.  Pointers with constant values are taken to point to
> nothing valid (as Arnd mentioned above, this is to detect invalid
> accesses to members of structs at address zero).
>
> One possible solution to the known address problem is to extend GCC
> attributes address and io that pin an object to a hardwired address
> to all targets (at the moment they're supported on just one or two
> targets).  I'm not sure this can still happen before GCC 11 releases
> sometime in April or May.
>
> Until then, another workaround is to convert the fixed address to
> a volatile pointer before using it for the access, along the lines
> below.  It should have only a negligible effect on efficiency.
>
> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
> index 4c09ba110204..76326b906010 100644
> --- a/arch/x86/kernel/tboot.c
> +++ b/arch/x86/kernel/tboot.c
> @@ -67,7 +67,9 @@ void __init tboot_probe(void)
>          /* Map and check for tboot UUID. */
>          set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
>          tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
> -       if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
> +       if (memcmp(&tboot_uuid,
> +                  (*(struct tboot* volatile *)(&tboot))->uuid,
> +                  sizeof(tboot->uuid))) {
>                  pr_warn("tboot at 0x%llx is invalid\n",

I think a stray 'volatile' would raise too many red flags here, but
I checked that the RELOC_HIDE() macro has the same effect, e.g.

@@ -66,7 +67,8 @@ void __init tboot_probe(void)

        /* Map and check for tboot UUID. */
        set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
-       tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
+       /* RELOC_HIDE to prevent gcc warnings about NULL pointer */
+       tboot = RELOC_HIDE(NULL, fix_to_virt(FIX_TBOOT_BASE));
        if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
                pr_warn("tboot at 0x%llx is invalid\n", boot_params.tboot_addr);
                tboot = NULL;

     Arnd

  reply	other threads:[~2021-03-22 22:50 UTC|newest]

Thread overview: 197+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-22 16:02 [PATCH 00/11] treewide: address gcc-11 -Wstringop-overread warnings Arnd Bergmann
2021-03-22 16:02 ` [Intel-gfx] " Arnd Bergmann
2021-03-22 16:02 ` Arnd Bergmann
2021-03-22 16:02 ` Arnd Bergmann
2021-03-22 16:02 ` Arnd Bergmann
2021-03-22 16:02 ` [PATCH 01/11] x86: compressed: avoid gcc-11 -Wstringop-overread warning Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` [Intel-gfx] " Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 23:30   ` [tip: x86/boot] x86/boot/compressed: Avoid " tip-bot2 for Arnd Bergmann
2021-03-22 16:02 ` [PATCH 02/11] x86: tboot: avoid Wstringop-overread-warning Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` [Intel-gfx] " Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 20:29   ` Ingo Molnar
2021-03-22 20:29     ` Ingo Molnar
2021-03-22 20:29     ` [Intel-gfx] " Ingo Molnar
2021-03-22 20:29     ` Ingo Molnar
2021-03-22 20:29     ` Ingo Molnar
2021-03-22 20:29     ` Ingo Molnar
2021-03-22 21:39     ` Arnd Bergmann
2021-03-22 21:39       ` Arnd Bergmann
2021-03-22 21:39       ` [Intel-gfx] " Arnd Bergmann
2021-03-22 21:39       ` Arnd Bergmann
2021-03-22 21:39       ` Arnd Bergmann
2021-03-22 21:39       ` Arnd Bergmann
2021-03-22 22:07     ` Martin Sebor
2021-03-22 22:07       ` Martin Sebor
2021-03-22 22:07       ` [Intel-gfx] " Martin Sebor
2021-03-22 22:07       ` Martin Sebor
2021-03-22 22:07       ` Martin Sebor
2021-03-22 22:07       ` Martin Sebor
2021-03-22 22:49       ` Arnd Bergmann [this message]
2021-03-22 22:49         ` Arnd Bergmann
2021-03-22 22:49         ` [Intel-gfx] " Arnd Bergmann
2021-03-22 22:49         ` Arnd Bergmann
2021-03-22 22:49         ` Arnd Bergmann
2021-03-22 22:49         ` Arnd Bergmann
2021-03-22 23:13       ` Ingo Molnar
2021-03-22 23:13         ` Ingo Molnar
2021-03-22 23:13         ` [Intel-gfx] " Ingo Molnar
2021-03-22 23:13         ` Ingo Molnar
2021-03-22 23:13         ` Ingo Molnar
2021-03-22 23:13         ` Ingo Molnar
2021-03-24  9:11       ` David Laight
2021-03-24  9:11         ` David Laight
2021-03-24  9:11         ` [Intel-gfx] " David Laight
2021-03-24  9:11         ` David Laight
2021-03-24  9:11         ` David Laight
2021-03-24  9:11         ` David Laight
2021-03-24 10:39         ` David Laight
2021-03-24 10:39           ` David Laight
2021-03-24 10:39           ` [Intel-gfx] " David Laight
2021-03-24 10:39           ` David Laight
2021-03-24 10:39           ` David Laight
2021-03-24 10:39           ` David Laight
2021-03-22 23:30   ` [tip: x86/boot] x86/boot/tboot: Avoid Wstringop-overread-warning tip-bot2 for Arnd Bergmann
2021-03-22 16:02 ` [PATCH 03/11] security: commoncap: fix -Wstringop-overread warning Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` [Intel-gfx] " Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:31   ` Christian Brauner
2021-03-22 16:31     ` Christian Brauner
2021-03-22 16:31     ` [Intel-gfx] " Christian Brauner
2021-03-22 16:31     ` Christian Brauner
2021-03-22 16:31     ` Christian Brauner
2021-03-22 16:31     ` Christian Brauner
2021-03-24 20:50   ` James Morris
2021-03-24 20:50     ` James Morris
2021-03-24 20:50     ` [Intel-gfx] " James Morris
2021-03-24 20:50     ` James Morris
2021-03-24 20:50     ` James Morris
2021-03-24 20:50     ` James Morris
2021-03-22 16:02 ` [PATCH 04/11] ath11: Wstringop-overread warning Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` [Intel-gfx] " Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-09-28  9:04   ` Kalle Valo
2021-09-28  9:04   ` Kalle Valo
2021-09-28  9:04     ` Kalle Valo
2021-09-28  9:04   ` Kalle Valo
2021-09-28  9:04     ` Kalle Valo
2021-09-28  9:04     ` [Intel-gfx] " Kalle Valo
2021-03-22 16:02 ` [PATCH 05/11] qnx: avoid -Wstringop-overread warning Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` [Intel-gfx] " Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02 ` [PATCH 06/11] cgroup: fix -Wzero-length-bounds warnings Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` [Intel-gfx] " Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-30  8:41   ` Michal Koutný
2021-03-30  8:41     ` Michal Koutný
2021-03-30  8:41     ` [Intel-gfx] " Michal Koutný
2021-03-30  8:41     ` Michal Koutný
2021-03-30  8:41     ` Michal Koutný
2021-03-30  8:41     ` Michal Koutný
2021-03-30  9:00     ` Arnd Bergmann
2021-03-30  9:00       ` Arnd Bergmann
2021-03-30  9:00       ` [Intel-gfx] " Arnd Bergmann
2021-03-30  9:00       ` Arnd Bergmann
2021-03-30  9:00       ` Arnd Bergmann
2021-03-30  9:00       ` Arnd Bergmann
2021-03-30 14:44       ` Michal Koutný
2021-03-30 14:44         ` Michal Koutný
2021-03-30 14:44         ` [Intel-gfx] " Michal Koutný
2021-03-30 14:44         ` Michal Koutný
2021-03-30 14:44         ` Michal Koutný
2021-03-30 14:44         ` Michal Koutný
2021-03-22 16:02 ` [PATCH 07/11] ARM: sharpsl_param: work around -Wstringop-overread warning Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` [Intel-gfx] " Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02 ` [PATCH 08/11] atmel: avoid gcc -Wstringop-overflow warning Arnd Bergmann
2021-03-22 16:02   ` [Intel-gfx] " Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02 ` [PATCH 09/11] scsi: lpfc: fix gcc -Wstringop-overread warning Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` [Intel-gfx] " Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02 ` [PATCH 10/11] drm/i915: avoid stringop-overread warning on pri_latency Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` [Intel-gfx] " Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-24 15:30   ` Jani Nikula
2021-03-24 15:30     ` Jani Nikula
2021-03-24 15:30     ` [Intel-gfx] " Jani Nikula
2021-03-24 15:30     ` Jani Nikula
2021-03-24 15:30     ` Jani Nikula
2021-03-24 15:30     ` Jani Nikula
2021-03-24 17:22     ` Ville Syrjälä
2021-03-24 17:22       ` Ville Syrjälä
2021-03-24 17:22       ` [Intel-gfx] " Ville Syrjälä
2021-03-24 17:22       ` Ville Syrjälä
2021-03-24 17:22       ` Ville Syrjälä
2021-03-24 17:22       ` Ville Syrjälä
2021-03-22 16:02 ` [PATCH 11/11] [RFC] drm/i915/dp: fix array overflow warning Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` [Intel-gfx] " Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-22 16:02   ` Arnd Bergmann
2021-03-25  8:05   ` Jani Nikula
2021-03-25  8:05     ` Jani Nikula
2021-03-25  8:05     ` [Intel-gfx] " Jani Nikula
2021-03-25  8:05     ` Jani Nikula
2021-03-25  8:05     ` Jani Nikula
2021-03-25  8:05     ` Jani Nikula
2021-03-25  9:53     ` Arnd Bergmann
2021-03-25  9:53       ` Arnd Bergmann
2021-03-25  9:53       ` [Intel-gfx] " Arnd Bergmann
2021-03-25  9:53       ` Arnd Bergmann
2021-03-25  9:53       ` Arnd Bergmann
2021-03-25  9:53       ` Arnd Bergmann
2021-03-25 14:49       ` Martin Sebor
2021-03-25 14:49         ` Martin Sebor
2021-03-25 14:49         ` [Intel-gfx] " Martin Sebor
2021-03-25 14:49         ` Martin Sebor
2021-03-25 14:49         ` Martin Sebor
2021-03-25 14:49         ` Martin Sebor
2021-03-30 10:56   ` Hans de Goede
2021-03-30 10:56     ` Hans de Goede
2021-03-30 10:56     ` [Intel-gfx] " Hans de Goede
2021-03-30 10:56     ` Hans de Goede
2021-03-30 10:56     ` Hans de Goede
2021-03-30 10:56     ` Hans de Goede
2021-03-22 19:10 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for treewide: address gcc-11 -Wstringop-overread warnings Patchwork
2021-03-22 19:12 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork
2021-03-22 19:38 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2021-03-23 15:30 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for treewide: address gcc-11 -Wstringop-overread warnings (rev2) Patchwork
2021-03-25 22:35 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for treewide: address gcc-11 -Wstringop-overread warnings (rev3) Patchwork
2021-03-30 11:50 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for treewide: address gcc-11 -Wstringop-overread warnings (rev4) Patchwork
2021-04-06  4:53 ` [PATCH 00/11] treewide: address gcc-11 -Wstringop-overread warnings Martin K. Petersen
2021-04-06  4:53   ` [Intel-gfx] " Martin K. Petersen
2021-04-06  4:53   ` Martin K. Petersen
2021-04-06  4:53   ` Martin K. Petersen
2021-04-06  4:53   ` Martin K. Petersen

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