On 2024/7/24 13:37, Andrew Morton wrote: > > 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 > > Before you just go and hit "reply", please: > a) Consider who else should be cc'ed > b) Prefer to cc a suitable mailing list as well > c) Ideally: find the original patch on the mailing list and do a > reply-to-all to that, adding suitable additional cc's > > *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** > > The -mm tree is included into linux-next via the mm-everything > branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm > and is updated there every 2-3 working days > > ------------------------------------------------------ > 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. It seems that the newest is v4, and the loongarch is missing. > > 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 >
