On Fri, Oct 24 2014, Weijie Yang <weijie.yang@xxxxxxxxxxx> wrote: > Fengguang Wu reported a BUG: Int 6: CR2 (null) on x86 platform in > 0-day Linux Kernel Performance Test: > > [ 0.000000] BRK [0x025ee000, 0x025eefff] PGTABLE > [ 0.000000] cma: dma_contiguous_reserve(limit 13ffe000) > [ 0.000000] cma: dma_contiguous_reserve: reserving 31 MiB for global area > [ 0.000000] BUG: Int 6: CR2 (null) > [ 0.000000] EDI c0000000 ESI (null) EBP 41c11ea4 EBX 425cc101 > [ 0.000000] ESP 41c11e98 ES 0000007b DS 0000007b > [ 0.000000] EDX 00000001 ECX (null) EAX 41cd8150 > [ 0.000000] vec 00000006 err (null) EIP 41072227 CS 00000060 flg 00210002 > [ 0.000000] Stack: 425cc150 (null) (null) 41c11ef4 41d4ee4d (null) 13ffe000 41c11ec4 > [ 0.000000] 41c2d900 (null) 13ffe000 (null) 4185793e 0000002e 410c2982 41c11f00 > [ 0.000000] 410c2df5 (null) (null) (null) 425cc150 00013efe (null) 41c11f28 > [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 3.17.0-next-20141008 #815 > [ 0.000000] 00000000 425cc101 41c11e48 41850786 41c11ea4 41d2b1db 41d95f71 00000006 > [ 0.000000] 00000000 c0000000 00000000 41c11ea4 425cc101 41c11e98 0000007b 0000007b > [ 0.000000] 00000001 00000000 41cd8150 00000006 00000000 41072227 00000060 00210002 > [ 0.000000] Call Trace: > [ 0.000000] [<41850786>] dump_stack+0x16/0x18 > [ 0.000000] [<41d2b1db>] early_idt_handler+0x6b/0x6b > [ 0.000000] [<41072227>] ? __phys_addr+0x2e/0xca > [ 0.000000] [<41d4ee4d>] cma_declare_contiguous+0x3c/0x2d7 > [ 0.000000] [<4185793e>] ? _raw_spin_unlock_irqrestore+0x59/0x91 > [ 0.000000] [<410c2982>] ? wake_up_klogd+0x8/0x33 > [ 0.000000] [<410c2df5>] ? console_unlock+0x448/0x461 > [ 0.000000] [<41d6d359>] dma_contiguous_reserve_area+0x27/0x47 > [ 0.000000] [<41d6d4d1>] dma_contiguous_reserve+0x158/0x163 > [ 0.000000] [<41d33e0f>] setup_arch+0x79b/0xc68 > [ 0.000000] [<4184c0b4>] ? printk+0x1c/0x1e > [ 0.000000] [<41d2b7cf>] start_kernel+0x9c/0x456 > [ 0.000000] [<41d2b2ca>] i386_start_kernel+0x79/0x7d > > see detail: 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: Michal Nazarewicz <mina86@xxxxxxxxxx> > --- > arch/x86/kernel/setup.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > 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 > -- > 1.7.0.4 > > -- Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Michał “mina86” Nazarewicz (o o) ooo +--<mpn@xxxxxxxxxx>--<xmpp:mina86@xxxxxxxxxx>--ooO--(_)--Ooo-- -- 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