Commit-ID: 3c325f8233c35fb35dec3744ba01634aab4ea36a Gitweb: http://git.kernel.org/tip/3c325f8233c35fb35dec3744ba01634aab4ea36a Author: Weijie Yang <weijie.yang@xxxxxxxxxxx> AuthorDate: Fri, 24 Oct 2014 17:00:34 +0800 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Tue, 28 Oct 2014 07:36:50 +0100 x86, cma: Reserve DMA contiguous area after initmem_init() Fengguang Wu reported a boot crash on the x86 platform via the 0-day Linux Kernel Performance Test: cma: dma_contiguous_reserve: reserving 31 MiB for global area BUG: Int 6: CR2 (null) [<41850786>] dump_stack+0x16/0x18 [<41d2b1db>] early_idt_handler+0x6b/0x6b [<41072227>] ? __phys_addr+0x2e/0xca [<41d4ee4d>] cma_declare_contiguous+0x3c/0x2d7 [<41d6d359>] dma_contiguous_reserve_area+0x27/0x47 [<41d6d4d1>] dma_contiguous_reserve+0x158/0x163 [<41d33e0f>] setup_arch+0x79b/0xc68 [<41d2b7cf>] start_kernel+0x9c/0x456 [<41d2b2ca>] i386_start_kernel+0x79/0x7d (See details at: https://lkml.org/lkml/2014/10/8/708) It is because dma_contiguous_reserve() is called before initmem_init() in x86, the variable high_memory is not initialized but accessed by __pa(high_memory) in dma_contiguous_reserve(). This patch moves dma_contiguous_reserve() after initmem_init() so that high_memory is initialized before accessed. Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx> Signed-off-by: Weijie Yang <weijie.yang@xxxxxxxxxxx> Acked-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Acked-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx> Cc: iamjoonsoo.kim@xxxxxxx Cc: 'Linux-MM' <linux-mm@xxxxxxxxx> Cc: 'Weijie Yang' <weijie.yang.kh@xxxxxxxxx> Link: http://lkml.kernel.org/r/000101cfef69%2431e528a0%2495af79e0%24%25yang@xxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/kernel/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 235cfd3..ab08aa2 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1128,7 +1128,6 @@ void __init setup_arch(char **cmdline_p) setup_real_mode(); memblock_set_current_limit(get_max_mapped()); - dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT); /* * NOTE: On x86-32, only from this point on, fixmaps are ready for use. @@ -1159,6 +1158,7 @@ void __init setup_arch(char **cmdline_p) early_acpi_boot_init(); initmem_init(); + dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT); /* * Reserve memory for crash kernel after SRAT is parsed so that it -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>