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Date: Wed, 27 Feb 2008 21:42:25 +0100 (CET) From: Thomas Gleixner <tglx@...utronix.de> To: Ingo Molnar <mingo@...e.hu> cc: Roland Dreier <rdreier@...co.com>, linux-kernel@...r.kernel.org, Thomas Mingarelli <thomas.mingarelli@...com> Subject: Re: hpwdt oops in clflush_cache_range On Wed, 27 Feb 2008, Ingo Molnar wrote: > * Thomas Gleixner <tglx@...utronix.de> wrote: > > > > [ 0.004000] Intel(R) Xeon(R) CPU 5160 @ 3.00GHz stepping 06 > > > > This one has 36bit physical address space. You can verify that via > > /proc/cpuinfo > > > > > [ 8425.910898] ACPI: PCI Interrupt 0000:01:04.0[A] -> GSI 21 (level, low) -> IRQ 21 > > > [ 8425.915097] hpwdt: New timer passed in is 30 seconds. > > > [ 8425.915139] BUG: unable to handle kernel paging request at ffffc20001a0a000 > > > [ 8425.919087] IP: [<ffffffff8021dacc>] clflush_cache_range+0xc/0x25 > > > [ 8425.919087] PGD 1bf80e067 PUD 1bf80f067 PMD 1bb497067 PTE 80000047000ee17b > > > > While the physical address of your ioremap is 47000ee000. > > > > 2^ 36 == 1000000000 > > ----> 47000ee000 > > > > So the fault is not very surprising. Unfortunately we do not check, > > whether physaddr is inside the valid physical address space. I whip up > > a patch to do that. > > also note that the driver would have faulted in a similar same way > anyway, the first time it tried to access that ioremap range. It's just > that due to the clflush we took the fault first in ioremap(). > > via the physical range check we'll do a more graceful exit and the > driver wont crash either. (it will just not work) Roland, does the patch below detect the wreckage ? Thanks, tglx ---------------> Subject: x86: check physical address range in ioremap From: Thomas Gleixner <tglx@...utronix.de> Date: Wed, 27 Feb 2008 20:57:40 +0100 Roland Dreier reported in http://lkml.org/lkml/2008/2/27/194 [ 8425.915139] BUG: unable to handle kernel paging request at ffffc20001a0a000 [ 8425.919087] IP: [<ffffffff8021dacc>] clflush_cache_range+0xc/0x25 [ 8425.919087] PGD 1bf80e067 PUD 1bf80f067 PMD 1bb497067 PTE 80000047000ee17b This is on a Intel machine with 36bit physical address space. The PTE entry references 47000ee000, which is outside of it. Add a check for the physical address space and warn/printk about the stupid caller. Signed-off-by: Thomas Gleixner <tglx@...utronix.de> --- arch/x86/mm/ioremap.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) Index: linux-2.6/arch/x86/mm/ioremap.c =================================================================== --- linux-2.6.orig/arch/x86/mm/ioremap.c +++ linux-2.6/arch/x86/mm/ioremap.c @@ -35,6 +35,18 @@ unsigned long __phys_addr(unsigned long } EXPORT_SYMBOL(__phys_addr); +static inline int phys_addr_valid(unsigned long addr) +{ + return addr < (1 << boot_cpu_data.x86_phys_bits); +} + +#else + +static inline int phys_addr_valid(unsigned long addr) +{ + return 1; +} + #endif int page_is_ram(unsigned long pagenr) @@ -118,6 +130,13 @@ static void __iomem *__ioremap(unsigned if (!size || last_addr < phys_addr) return NULL; + if (!phys_addr_valid(phys_addr)) { + printk(KERN_WARNING "ioremap: invalid physical address %lx\n", + phys_addr); + WARN_ON_ONCE(1); + return NULL; + } + /* * Don't remap the low PCI/ISA area, it's always mapped.. */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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