From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lU8ot-0055ZC-UF for kexec@lists.infradead.org; Wed, 07 Apr 2021 14:06:14 +0000 From: Lianbo Jiang Subject: [PATCH] x86/efi: Do not release sub-1MB memory regions when the crashkernel option is specified Date: Wed, 7 Apr 2021 22:03:16 +0800 Message-Id: <20210407140316.30210-1-lijiang@redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: linux-kernel@vger.kernel.org Cc: linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org, x86@kernel.org, ardb@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dvhart@infradead.org, andy@infradead.org, hpa@zytor.com, kexec@lists.infradead.org, bhe@redhat.com, dyoung@redhat.com Some sub-1MB memory regions may be reserved by EFI boot services, and the memory regions will be released later in the efi_free_boot_services(). Currently, always reserve all sub-1MB memory regions when the crashkernel option is specified, but unfortunately EFI boot services may have already reserved some sub-1MB memory regions before the crash_reserve_low_1M() is called, which makes that the crash_reserve_low_1M() only own the remaining sub-1MB memory regions, not all sub-1MB memory regions, because, subsequently EFI boot services will free its own sub-1MB memory regions. Eventually, DMA will be able to allocate memory from the sub-1MB area and cause the following error: crash> kmem -s |grep invalid kmem: dma-kmalloc-512: slab: ffffd52c40001900 invalid freepointer: ffff9403c0067300 kmem: dma-kmalloc-512: slab: ffffd52c40001900 invalid freepointer: ffff9403c0067300 crash> vtop ffff9403c0067300 VIRTUAL PHYSICAL ffff9403c0067300 67300 --->The physical address falls into this range [0x0000000000063000-0x000000000008efff] kernel debugging log: ... [ 0.008927] memblock_reserve: [0x0000000000010000-0x0000000000013fff] efi_reserve_boot_services+0x85/0xd0 [ 0.008930] memblock_reserve: [0x0000000000063000-0x000000000008efff] efi_reserve_boot_services+0x85/0xd0 ... [ 0.009425] memblock_reserve: [0x0000000000000000-0x00000000000fffff] crash_reserve_low_1M+0x2c/0x49 ... [ 0.010586] Zone ranges: [ 0.010587] DMA [mem 0x0000000000001000-0x0000000000ffffff] [ 0.010589] DMA32 [mem 0x0000000001000000-0x00000000ffffffff] [ 0.010591] Normal [mem 0x0000000100000000-0x0000000c7fffffff] [ 0.010593] Device empty ... [ 8.814894] __memblock_free_late: [0x0000000000063000-0x000000000008efff] efi_free_boot_services+0x14b/0x23b [ 8.815793] __memblock_free_late: [0x0000000000010000-0x0000000000013fff] efi_free_boot_services+0x14b/0x23b Do not release sub-1MB memory regions even though they are reserved by EFI boot services, so that always reserve all sub-1MB memory regions when the crashkernel option is specified. Signed-off-by: Lianbo Jiang --- arch/x86/platform/efi/quirks.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c index 67d93a243c35..637f932c4fd4 100644 --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c @@ -18,6 +18,7 @@ #include #include #include +#include #define EFI_MIN_RESERVE 5120 @@ -303,6 +304,19 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size) */ static __init bool can_free_region(u64 start, u64 size) { + /* + * Some sub-1MB memory regions may be reserved by EFI boot + * services, and these memory regions will be released later + * in the efi_free_boot_services(). + * + * Do not release sub-1MB memory regions even though they are + * reserved by EFI boot services, because, always reserve all + * sub-1MB memory when the crashkernel option is specified. + */ + if (cmdline_find_option(boot_command_line, "crashkernel", NULL, 0) > 0 + && (start + size < (1<<20))) + return false; + if (start + size > __pa_symbol(_text) && start <= __pa_symbol(_end)) return false; -- 2.17.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec