+ crash-fix-x86_32-crash-memory-reserve-dead-loop-bug.patch added to mm-nonmm-unstable branch - Linux-stable-mirror

24 Jul 2024

The patch titled
     Subject: crash: fix x86_32 crash memory reserve dead loop bug
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     crash-fix-x86_32-crash-memory-reserve-dead-loop-bug.patch
This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Jinjie Ruan ruanjinjie@huawei.com
Subject: crash: fix x86_32 crash memory reserve dead loop bug
Date: Thu, 18 Jul 2024 11:54:42 +0800
Patch series "crash: Fix x86_32 memory reserve dead loop bug", v3.
Fix two bugs for x86_32 crash memory reserve, and prepare to apply generic
crashkernel reservation to 32bit system.  Then use generic interface to
simplify crashkernel reservation for ARM32.
This patch (of 3):
On x86_32 Qemu machine with 1GB memory, the cmdline "crashkernel=1G,high"
will cause system stall as below:
ACPI: Reserving FACP table memory at [mem 0x3ffe18b8-0x3ffe192b]
    ACPI: Reserving DSDT table memory at [mem 0x3ffe0040-0x3ffe18b7]
    ACPI: Reserving FACS table memory at [mem 0x3ffe0000-0x3ffe003f]
    ACPI: Reserving APIC table memory at [mem 0x3ffe192c-0x3ffe19bb]
    ACPI: Reserving HPET table memory at [mem 0x3ffe19bc-0x3ffe19f3]
    ACPI: Reserving WAET table memory at [mem 0x3ffe19f4-0x3ffe1a1b]
    143MB HIGHMEM available.
    879MB LOWMEM available.
      mapped low ram: 0 - 36ffe000
      low ram: 0 - 36ffe000
     (stall here)
The reason is that the CRASH_ADDR_LOW_MAX is equal to CRASH_ADDR_HIGH_MAX
on x86_32, the first high crash kernel memory reservation will fail, then
go into the "retry" loop and never came out as below.
-> reserve_crashkernel_generic() and high is true
 -> alloc at [CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX] fail
    -> alloc at [0, CRASH_ADDR_LOW_MAX] fail and repeatedly
       (because CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX).
Fix it by prevent crashkernel=,high from being parsed successfully on 32bit
system with a architecture-defined macro.
After this patch, the 'crashkernel=,high' for 32bit system can't succeed,
and it has no chance to call reserve_crashkernel_generic(), therefore this
issue on x86_32 is solved.
Link: https://lkml.kernel.org/r/20240718035444.2977105-1-ruanjinjie@huawei.com
Link: https://lkml.kernel.org/r/20240718035444.2977105-2-ruanjinjie@huawei.com
Fixes: 9c08a2a139fe ("x86: kdump: use generic interface to simplify crashkernel reservation code")
Signed-off-by: Jinjie Ruan ruanjinjie@huawei.com
Signed-off-by: Baoquan He bhe@redhat.com
Tested-by: Jinjie Ruan ruanjinjie@huawei.com
Cc: Albert Ou aou@eecs.berkeley.edu
Cc: Andrew Davis afd@ti.com
Cc: Arnd Bergmann arnd@arndb.de
Cc: Borislav Petkov bp@alien8.de
Cc: Catalin Marinas catalin.marinas@arm.com
Cc: Chen Jiahao chenjiahao16@huawei.com
Cc: Dave Hansen dave.hansen@linux.intel.com
Cc: Dave Young dyoung@redhat.com
Cc: Eric DeVolder eric.devolder@oracle.com
Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org
Cc: Hari Bathini hbathini@linux.ibm.com
Cc: Helge Deller deller@gmx.de
Cc: "H. Peter Anvin" hpa@zytor.com
Cc: Ingo Molnar mingo@redhat.com
Cc: Javier Martinez Canillas javierm@redhat.com
Cc: Linus Walleij linus.walleij@linaro.org
Cc: Palmer Dabbelt palmer@dabbelt.com
Cc: Paul Walmsley paul.walmsley@sifive.com
Cc: Rob Herring robh@kernel.org
Cc: Russell King linux@armlinux.org.uk
Cc: Thomas Gleixner tglx@linutronix.de
Cc: Vivek Goyal vgoyal@redhat.com
Cc: Will Deacon will@kernel.org
Cc: Zhen Lei thunder.leizhen@huawei.com
Cc: stable@vger.kernel.org
Signed-off-by: Andrew Morton akpm@linux-foundation.org
---
arch/arm64/include/asm/crash_reserve.h |    2 ++
 arch/riscv/include/asm/crash_reserve.h |    2 ++
 arch/x86/include/asm/crash_reserve.h   |    1 +
 kernel/crash_reserve.c                 |    2 +-
 4 files changed, 6 insertions(+), 1 deletion(-)

--- a/arch/arm64/include/asm/crash_reserve.h~crash-fix-x86_32-crash-memory-reserve-dead-loop-bug
+++ a/arch/arm64/include/asm/crash_reserve.h
@@ -7,4 +7,6 @@
#define CRASH_ADDR_LOW_MAX              arm64_dma_phys_limit
 #define CRASH_ADDR_HIGH_MAX             (PHYS_MASK + 1)
+
+#define HAVE_ARCH_CRASHKERNEL_RESERVATION_HIGH
 #endif
--- a/arch/riscv/include/asm/crash_reserve.h~crash-fix-x86_32-crash-memory-reserve-dead-loop-bug
+++ a/arch/riscv/include/asm/crash_reserve.h
@@ -7,5 +7,7 @@
 #define CRASH_ADDR_LOW_MAX		dma32_phys_limit
 #define CRASH_ADDR_HIGH_MAX		memblock_end_of_DRAM()
+#define HAVE_ARCH_CRASHKERNEL_RESERVATION_HIGH
+
 extern phys_addr_t memblock_end_of_DRAM(void);
 #endif
--- a/arch/x86/include/asm/crash_reserve.h~crash-fix-x86_32-crash-memory-reserve-dead-loop-bug
+++ a/arch/x86/include/asm/crash_reserve.h
@@ -26,6 +26,7 @@ extern unsigned long swiotlb_size_or_def
 #else
 # define CRASH_ADDR_LOW_MAX     SZ_4G
 # define CRASH_ADDR_HIGH_MAX    SZ_64T
+#define HAVE_ARCH_CRASHKERNEL_RESERVATION_HIGH
 #endif
# define DEFAULT_CRASH_KERNEL_LOW_SIZE crash_low_size_default()
--- a/kernel/crash_reserve.c~crash-fix-x86_32-crash-memory-reserve-dead-loop-bug
+++ a/kernel/crash_reserve.c
@@ -305,7 +305,7 @@ int __init parse_crashkernel(char *cmdli
    /* crashkernel=X[@offset] */
    ret = __parse_crashkernel(cmdline, system_ram, crash_size,
    			crash_base, NULL);
-#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
+#ifdef HAVE_ARCH_CRASHKERNEL_RESERVATION_HIGH
    /*
     * If non-NULL 'high' passed in and no normal crashkernel
     * setting detected, try parsing crashkernel=,high|low.
_
Patches currently in -mm which might be from ruanjinjie@huawei.com are
crash-fix-x86_32-crash-memory-reserve-dead-loop-bug.patch
crash-fix-x86_32-crash-memory-reserve-dead-loop-bug-at-high.patch
arm-use-generic-interface-to-simplify-crashkernel-reservation.patch

    