Re: [PATCH] mm, kasan: don't poison boot memory

From: Mike Rapoport <rppt@linux.ibm.com>
To: George Kennedy <george.kennedy@oracle.com>
Cc: Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Marco Elver <elver@google.com>,
	Dhaval Giani <dhaval.giani@oracle.com>,
	David Hildenbrand <david@redhat.com>,
	Andrey Konovalov <andreyknvl@google.com>,
	Kevin Brodsky <kevin.brodsky@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Branislav Rankov <Branislav.Rankov@arm.com>,
	kasan-dev <kasan-dev@googlegroups.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Christoph Hellwig <hch@infradead.org>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Alexander Potapenko <glider@google.com>,
	Evgenii Stepanov <eugenis@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Konrad Rzeszutek Wilk <konrad@darnok.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Peter Collingbourne <pcc@google.com>,
	Linux Memory Management List <linux-mm@kvack.org>,
	Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH] mm, kasan: don't poison boot memory
Date: Tue, 23 Feb 2021 23:32:37 +0200	[thread overview]
Message-ID: <20210223213237.GI1741768@linux.ibm.com> (raw)
In-Reply-To: <af06267d-00cd-d4e0-1985-b06ce7c993a3@oracle.com>

On Tue, Feb 23, 2021 at 04:16:44PM -0500, George Kennedy wrote:
> 
> 
> On 2/23/2021 3:09 PM, Mike Rapoport wrote:
> > On Tue, Feb 23, 2021 at 01:05:05PM -0500, George Kennedy wrote:
> > > On 2/23/2021 10:47 AM, Mike Rapoport wrote:
> > > 
> > > It now crashes here:
> > > 
> > > [    0.051019] ACPI: Early table checksum verification disabled
> > > [    0.056721] ACPI: RSDP 0x00000000BFBFA014 000024 (v02 BOCHS )
> > > [    0.057874] ACPI: XSDT 0x00000000BFBF90E8 00004C (v01 BOCHS BXPCFACP
> > > 00000001      01000013)
> > > [    0.059590] ACPI: FACP 0x00000000BFBF5000 000074 (v01 BOCHS BXPCFACP
> > > 00000001 BXPC 00000001)
> > > [    0.061306] ACPI: DSDT 0x00000000BFBF6000 00238D (v01 BOCHS BXPCDSDT
> > > 00000001 BXPC 00000001)
> > > [    0.063006] ACPI: FACS 0x00000000BFBFD000 000040
> > > [    0.063938] ACPI: APIC 0x00000000BFBF4000 000090 (v01 BOCHS BXPCAPIC
> > > 00000001 BXPC 00000001)
> > > [    0.065638] ACPI: HPET 0x00000000BFBF3000 000038 (v01 BOCHS BXPCHPET
> > > 00000001 BXPC 00000001)
> > > [    0.067335] ACPI: BGRT 0x00000000BE49B000 000038 (v01 INTEL EDK2
> > > 00000002      01000013)
> > > [    0.069030] ACPI: iBFT 0x00000000BE453000 000800 (v01 BOCHS BXPCFACP
> > > 00000000      00000000)
> > > [    0.070734] XXX acpi_find_ibft_region:
> > > [    0.071468] XXX iBFT, status=0
> > > [    0.072073] XXX about to call acpi_put_table()...
> > > ibft_addr=ffffffffff240000
> > > [    0.073449] XXX acpi_find_ibft_region(EXIT):
> > > PANIC: early exception 0x0e IP 10:ffffffff9259f439 error 0 cr2
> > > 0xffffffffff240004
> > Right, I've missed the dereference of the ibft_addr after
> > acpi_find_ibft_region().
> > 
> > With this change to iscsi_ibft_find.c instead of the previous one it should
> > be better:
> > 
> > diff --git a/drivers/firmware/iscsi_ibft_find.c b/drivers/firmware/iscsi_ibft_find.c
> > index 64bb94523281..1be7481d5c69 100644
> > --- a/drivers/firmware/iscsi_ibft_find.c
> > +++ b/drivers/firmware/iscsi_ibft_find.c
> > @@ -80,6 +80,27 @@ static int __init find_ibft_in_mem(void)
> >   done:
> >   	return len;
> >   }
> > +
> > +static void __init acpi_find_ibft_region(unsigned long *sizep)
> > +{
> > +	int i;
> > +	struct acpi_table_header *table = NULL;
> > +	acpi_status status;
> > +
> > +	if (acpi_disabled)
> > +		return;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(ibft_signs) && !ibft_addr; i++) {
> > +		status = acpi_get_table(ibft_signs[i].sign, 0, &table);
> > +		if (ACPI_SUCCESS(status)) {
> > +			ibft_addr = (struct acpi_table_ibft *)table;
> > +			*sizep = PAGE_ALIGN(ibft_addr->header.length);
> > +			acpi_put_table(table);
> > +			break;
> > +		}
> > +	}
> > +}
> > +
> >   /*
> >    * Routine used to find the iSCSI Boot Format Table. The logical
> >    * kernel address is set in the ibft_addr global variable.
> > @@ -91,14 +112,16 @@ unsigned long __init find_ibft_region(unsigned long *sizep)
> >   	/* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will
> >   	 * only use ACPI for this */
> > -	if (!efi_enabled(EFI_BOOT))
> > +	if (!efi_enabled(EFI_BOOT)) {
> >   		find_ibft_in_mem();
> > -
> > -	if (ibft_addr) {
> >   		*sizep = PAGE_ALIGN(ibft_addr->header.length);
> > -		return (u64)virt_to_phys(ibft_addr);
> > +	} else {
> > +		acpi_find_ibft_region(sizep);
> >   	}
> > +	if (ibft_addr)
> > +		return (u64)virt_to_phys(ibft_addr);
> > +
> >   	*sizep = 0;
> >   	return 0;
> >   }
> Mike,
> 
> No luck. Back to the original KASAN ibft_init crash.
> 
> I ran with only the above patch from you. Was that what you wanted? Your
> previous patch had a section defined out by #if 0. Was that supposed to be
> in there as well?

Sorry, I wasn't clear, but I meant to use the first patch and only replace
changes to iscsi_ibft_find.c with the new patch. 

Here's the full patch to be sure we're on the same page:

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 7bdc0239a943..c118dd54a747 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -1551,6 +1551,7 @@ void __init acpi_boot_table_init(void)
 	if (acpi_disabled)
 		return;
 
+#if 0
 	/*
 	 * Initialize the ACPI boot-time table parser.
 	 */
@@ -1558,6 +1559,7 @@ void __init acpi_boot_table_init(void)
 		disable_acpi();
 		return;
 	}
+#endif
 
 	acpi_table_parse(ACPI_SIG_BOOT, acpi_parse_sbf);
 
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index d883176ef2ce..c8a07a7b9577 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1032,6 +1032,14 @@ void __init setup_arch(char **cmdline_p)
 	 */
 	find_smp_config();
 
+	/*
+	 * Initialize the ACPI boot-time table parser.
+	 */
+	if (acpi_table_init()) {
+		disable_acpi();
+		return;
+	}
+
 	reserve_ibft_region();
 
 	early_alloc_pgt_buf();
diff --git a/drivers/firmware/iscsi_ibft_find.c b/drivers/firmware/iscsi_ibft_find.c
index 64bb94523281..1be7481d5c69 100644
--- a/drivers/firmware/iscsi_ibft_find.c
+++ b/drivers/firmware/iscsi_ibft_find.c
@@ -80,6 +80,27 @@ static int __init find_ibft_in_mem(void)
 done:
 	return len;
 }
+
+static void __init acpi_find_ibft_region(unsigned long *sizep)
+{
+	int i;
+	struct acpi_table_header *table = NULL;
+	acpi_status status;
+
+	if (acpi_disabled)
+		return;
+
+	for (i = 0; i < ARRAY_SIZE(ibft_signs) && !ibft_addr; i++) {
+		status = acpi_get_table(ibft_signs[i].sign, 0, &table);
+		if (ACPI_SUCCESS(status)) {
+			ibft_addr = (struct acpi_table_ibft *)table;
+			*sizep = PAGE_ALIGN(ibft_addr->header.length);
+			acpi_put_table(table);
+			break;
+		}
+	}
+}
+
 /*
  * Routine used to find the iSCSI Boot Format Table. The logical
  * kernel address is set in the ibft_addr global variable.
@@ -91,14 +112,16 @@ unsigned long __init find_ibft_region(unsigned long *sizep)
 	/* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will
 	 * only use ACPI for this */
 
-	if (!efi_enabled(EFI_BOOT))
+	if (!efi_enabled(EFI_BOOT)) {
 		find_ibft_in_mem();
-
-	if (ibft_addr) {
 		*sizep = PAGE_ALIGN(ibft_addr->header.length);
-		return (u64)virt_to_phys(ibft_addr);
+	} else {
+		acpi_find_ibft_region(sizep);
 	}
 
+	if (ibft_addr)
+		return (u64)virt_to_phys(ibft_addr);
+
 	*sizep = 0;
 	return 0;
 }
 

-- 
Sincerely yours,
Mike.

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