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