Messages in this thread Patch in this message | | | Date | Thu, 30 Jul 2009 12:17:57 -0700 | From | "Pallipadi, Venkatesh" <> | Subject | Re: PAT wc & vmap mapping count issue ? |
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On Thu, Jul 30, 2009 at 10:06:33AM -0700, Jerome Glisse wrote: > On Thu, 2009-07-30 at 13:11 +0200, Jerome Glisse wrote: > > Hello, > > > > I think i am facing a PAT issue code (at bottom of the mail) leads > > to mapping count issue such as one at bottom of mail. Is my test > > code buggy ? If so what is wrong with it ? Otherwise how could i > > track this down ? (Tested with lastest Linus tree). Note that > > the mapping count sometimes is negative, sometimes it's positive > > but without proper mapping. > > > > (With AMD Athlon(tm) Dual Core Processor 4450e) > > > > Note that bad page might takes time to happen 256 pages is bit > > too little either increasing that or doing memory hungry task > > will helps triggering the bug faster. > > > > Cheers, > > Jerome > > > > Jul 30 11:12:36 localhost kernel: BUG: Bad page state in process bash > > pfn:6daed > > Jul 30 11:12:36 localhost kernel: page:ffffea0001b6bb40 > > flags:4000000000000000 count:1 mapcount:1 mapping:(null) index:6d8 > > Jul 30 11:12:36 localhost kernel: Pid: 1876, comm: bash Not tainted > > 2.6.31-rc2 #30 > > Jul 30 11:12:36 localhost kernel: Call Trace: > > Jul 30 11:12:36 localhost kernel: [<ffffffff81098570>] bad_page > > +0xf8/0x10d > > Jul 30 11:12:36 localhost kernel: [<ffffffff810997aa>] > > get_page_from_freelist+0x357/0x475 > > Jul 30 11:12:36 localhost kernel: [<ffffffff810a72e3>] ? cond_resched > > +0x9/0xb > > Jul 30 11:12:36 localhost kernel: [<ffffffff810a9958>] ? copy_page_range > > +0x4cc/0x558 > > Jul 30 11:12:36 localhost kernel: [<ffffffff810999e0>] > > __alloc_pages_nodemask+0x118/0x562 > > Jul 30 11:12:36 localhost kernel: [<ffffffff812a92c3>] ? > > _spin_unlock_irq+0xe/0x11 > > Jul 30 11:12:36 localhost kernel: [<ffffffff810a9dda>] > > alloc_pages_node.clone.0+0x14/0x16 > > Jul 30 11:12:36 localhost kernel: [<ffffffff810aa0b1>] do_wp_page > > +0x2d5/0x57d > > Jul 30 11:12:36 localhost kernel: [<ffffffff810aac00>] handle_mm_fault > > +0x586/0x5e0 > > Jul 30 11:12:36 localhost kernel: [<ffffffff812ab635>] do_page_fault > > +0x20a/0x21f > > Jul 30 11:12:36 localhost kernel: [<ffffffff812a968f>] page_fault > > +0x1f/0x30 > > Jul 30 11:12:36 localhost kernel: Disabling lock debugging due to kernel > > taint > > > > #define NPAGEST 256 > > void test_wc(void) > > { > > struct page *pages[NPAGEST]; > > int i, j; > > void *virt; > > > > for (i = 0; i < NPAGEST; i++) { > > pages[i] = NULL; > > } > > for (i = 0; i < NPAGEST; i++) { > > pages[i] = alloc_page(__GFP_DMA32 | GFP_USER); > > if (pages[i] == NULL) { > > printk(KERN_ERR "Failled allocating page %d\n", > > i); > > goto out_free; > > } > > if (!PageHighMem(pages[i])) > > if (set_memory_wc((unsigned long) > > page_address(pages[i]), 1)) { > > printk(KERN_ERR "Failled setting page %d > > wc\n", i); > > goto out_free; > > } > > } > > virt = vmap(pages, NPAGEST, 0, > > pgprot_writecombine(PAGE_KERNEL)); > > if (virt == NULL) { > > printk(KERN_ERR "Failled vmapping\n"); > > goto out_free; > > } > > vunmap(virt); > > out_free: > > for (i = 0; i < NPAGEST; i++) { > > if (pages[i]) { > > if (!PageHighMem(pages[i])) > > set_memory_wb((unsigned long) > > page_address(pages[i]), 1); > > __free_page(pages[i]); > > } > > } > > } > > vmaping doesn't seems to be involved with the corruption simply > setting some pages with set_memory_wc is enough. > >
This seems to be a regression from changeset 3869c4aa18835c8c61b44bd0f3ace36e9d3b5bd0
Below test patch should fix the problem. Can you please try it and let use know. We can then send a cleaner patch with changelog etc to upstream+stable kernels.
Thanks, Venki
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> --- arch/x86/mm/pageattr.c | 9 ++++++--- 1 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 1b734d7..895d90e 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -997,12 +997,15 @@ EXPORT_SYMBOL(set_memory_array_uc); int _set_memory_wc(unsigned long addr, int numpages) { int ret; + unsigned long addr_copy = addr; + ret = change_page_attr_set(&addr, numpages, __pgprot(_PAGE_CACHE_UC_MINUS), 0); - if (!ret) { - ret = change_page_attr_set(&addr, numpages, - __pgprot(_PAGE_CACHE_WC), 0); + ret = change_page_attr_set_clr(&addr_copy, numpages, + __pgprot(_PAGE_CACHE_WC), + __pgprot(_PAGE_CACHE_MASK), + 0, 0, NULL); } return ret; } -- 1.6.0.6
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