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/crash-fix-x86_32-crash-memory-reserve-dead-loop-bug.patch
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@xxxxxxxxxx>
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@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20240718035444.2977105-2-ruanjinjie@xxxxxxxxxx
Fixes: 9c08a2a139fe ("x86: kdump: use generic interface to simplify crashkernel reservation code")
Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
Tested-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Andrew Davis <afd@xxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Chen Jiahao <chenjiahao16@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Eric DeVolder <eric.devolder@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Hari Bathini <hbathini@xxxxxxxxxxxxx>
Cc: Helge Deller <deller@xxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Javier Martinez Canillas <javierm@xxxxxxxxxx>
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxx 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
