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

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On 2/24/2021 5:37 AM, Mike Rapoport wrote:
On Tue, Feb 23, 2021 at 04:46:28PM -0500, George Kennedy wrote:
Mike,

Still no luck.

[   30.193723] iscsi: registered transport (iser)
[   30.195970] iBFT detected.
[   30.196571] BUG: unable to handle page fault for address: ffffffffff240004
Hmm, we cannot set ibft_addr to early pointer to the ACPI table.
Let's try something more disruptive and move the reservation back to
iscsi_ibft_find.c.

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..c615ce96c9a2 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -570,16 +570,6 @@ void __init reserve_standard_io_resources(void)
} -static __init void reserve_ibft_region(void)
-{
-	unsigned long addr, size = 0;
-
-	addr = find_ibft_region(&size);
-
-	if (size)
-		memblock_reserve(addr, size);
-}
-
  static bool __init snb_gfx_workaround_needed(void)
  {
  #ifdef CONFIG_PCI
@@ -1032,6 +1022,12 @@ void __init setup_arch(char **cmdline_p)
  	 */
  	find_smp_config();
+ /*
+	 * Initialize the ACPI boot-time table parser.
+	 */
+	if (acpi_table_init())
+		disable_acpi();
+
  	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..01be513843d6 100644
--- a/drivers/firmware/iscsi_ibft_find.c
+++ b/drivers/firmware/iscsi_ibft_find.c
@@ -47,7 +47,25 @@ static const struct {
  #define VGA_MEM 0xA0000 /* VGA buffer */
  #define VGA_SIZE 0x20000 /* 128kB */
-static int __init find_ibft_in_mem(void)
+static void __init *acpi_find_ibft_region(void)
+{
+	int i;
+	struct acpi_table_header *table = NULL;
+	acpi_status status;
+
+	if (acpi_disabled)
+		return NULL;
+
+	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))
+			return table;
+	}
+
+	return NULL;
+}
+
+static void __init *find_ibft_in_mem(void)
  {
  	unsigned long pos;
  	unsigned int len = 0;
@@ -70,35 +88,44 @@ static int __init find_ibft_in_mem(void)
  				/* if the length of the table extends past 1M,
  				 * the table cannot be valid. */
  				if (pos + len <= (IBFT_END-1)) {
-					ibft_addr = (struct acpi_table_ibft *)virt;
  					pr_info("iBFT found at 0x%lx.\n", pos);
-					goto done;
+					return virt;
  				}
  			}
  		}
  	}
-done:
-	return len;
+
+	return NULL;
  }
+
+static void __init *find_ibft(void)
+{
+	/* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will
+	 * only use ACPI for this */
+	if (!efi_enabled(EFI_BOOT))
+		return find_ibft_in_mem();
+	else
+		return acpi_find_ibft_region();
+}
+
  /*
   * Routine used to find the iSCSI Boot Format Table. The logical
   * kernel address is set in the ibft_addr global variable.
   */
-unsigned long __init find_ibft_region(unsigned long *sizep)
+void __init reserve_ibft_region(void)
  {
-	ibft_addr = NULL;
+	struct acpi_table_ibft *table;
+	unsigned long size;
- /* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will
-	 * only use ACPI for this */
+	table = find_ibft();
+	if (!table)
+		return;
- 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);
-	}
+	size = PAGE_ALIGN(table->header.length);
+	memblock_reserve(virt_to_phys(table), size);
- *sizep = 0;
-	return 0;
+	if (efi_enabled(EFI_BOOT))
+		acpi_put_table(&table->header);
+	else
+		ibft_addr = table;
  }
diff --git a/include/linux/iscsi_ibft.h b/include/linux/iscsi_ibft.h
index b7b45ca82bea..da813c891990 100644
--- a/include/linux/iscsi_ibft.h
+++ b/include/linux/iscsi_ibft.h
@@ -26,13 +26,9 @@ extern struct acpi_table_ibft *ibft_addr;
   * mapped address is set in the ibft_addr variable.
   */
  #ifdef CONFIG_ISCSI_IBFT_FIND
-unsigned long find_ibft_region(unsigned long *sizep);
+void reserve_ibft_region(void);
  #else
-static inline unsigned long find_ibft_region(unsigned long *sizep)
-{
-	*sizep = 0;
-	return 0;
-}
+static inline void reserve_ibft_region(void) {}
  #endif
#endif /* ISCSI_IBFT_H */

Still no luck Mike,

We're back to the original problem where the only thing that worked was to run "SetPageReserved(page)" before calling "kmap(page)". The page is being "freed" before ibft_init() is called as a result of the recent buddy page freeing changes.

[   30.385207] iscsi: registered transport (iser)
[   30.387462] iBFT detected.
[   30.388042] ==================================================================
[   30.388119] BUG: KASAN: use-after-free in ibft_init+0x134/0xc33
[   30.388119] Read of size 4 at addr ffff8880be453004 by task swapper/0/1
[   30.388119]
[   30.388119] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.11.0-f9593a0 #11
[   30.388119] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
[   30.388119] Call Trace:
[   30.388119]  dump_stack+0xdb/0x120
[   30.388119]  ? ibft_init+0x134/0xc33
[   30.388119]  print_address_description.constprop.7+0x41/0x60
[   30.388119]  ? ibft_init+0x134/0xc33
[   30.388119]  ? ibft_init+0x134/0xc33
[   30.388119]  kasan_report.cold.10+0x78/0xd1
[   30.388119]  ? ibft_init+0x134/0xc33
[   30.388119]  __asan_report_load_n_noabort+0xf/0x20
[   30.388119]  ibft_init+0x134/0xc33
[   30.388119]  ? write_comp_data+0x2f/0x90
[   30.388119]  ? ibft_check_initiator_for+0x159/0x159
[   30.388119]  ? write_comp_data+0x2f/0x90
[   30.388119]  ? ibft_check_initiator_for+0x159/0x159
[   30.388119]  do_one_initcall+0xc4/0x3e0
[   30.388119]  ? perf_trace_initcall_level+0x3e0/0x3e0
[   30.388119]  ? unpoison_range+0x14/0x40
[   30.388119]  ? ____kasan_kmalloc.constprop.5+0x8f/0xc0
[   30.388119]  ? kernel_init_freeable+0x420/0x652

George








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