From mboxrd@z Thu Jan 1 00:00:00 1970 From: laurent.pinchart@ideasonboard.com (Laurent Pinchart) Date: Mon, 21 Apr 2014 11:53:12 +0200 Subject: [PATCH] arm: dma-mapping: Fix mapping size value In-Reply-To: References: Message-ID: <10358035.cGxAQP71WM@avalon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Ritesh, On Monday 21 April 2014 09:31:38 Ritesh Harjani wrote: > Fixed the commit message. Please find the new patch below: Thank you. Your mail has wrapped lines and converted tabs to whitespaces. Could you please fix that and resubmit the patch on a mail of its own (use git send-email to avoid white space issues), with the subject set to "[PATCH v2] arm: dma-mapping: Fix mapping size value" ? > 68efd7d2fb("arm: dma-mapping: remove order parameter from > arm_iommu_create_mapping()") is causing kernel panic > because it wrongly sets the mapping->size value. > > Unable to handle kernel NULL pointer dereference at virtual > address 000000a0 > pgd = e7a84000 > [000000a0] *pgd=00000000 > ... > PC is at bitmap_clear+0x48/0xd0 > LR is at __iommu_remove_mapping+0x130/ > 0x164 > > > Fix it by correcting the mapping->size value. > > Signed-off-by: Ritesh Harjani > Acked-by: Laurent Pinchart > --- > arch/arm/mm/dma-mapping.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > index f62aa06..6b00be1 100644 > --- a/arch/arm/mm/dma-mapping.c > +++ b/arch/arm/mm/dma-mapping.c > @@ -1963,8 +1963,8 @@ arm_iommu_create_mapping(struct bus_type *bus, > dma_addr_t base, size_t size) > mapping->nr_bitmaps = 1; > mapping->extensions = extensions; > mapping->base = base; > - mapping->size = bitmap_size << PAGE_SHIFT; > mapping->bits = BITS_PER_BYTE * bitmap_size; > + mapping->size = mapping->bits << PAGE_SHIFT; > > spin_lock_init(&mapping->lock); > > > -- > 1.8.1.3 > > On Mon, Apr 21, 2014 at 4:06 AM, Laurent Pinchart > > wrote: > > Hi Ritesh, > > > > On Saturday 19 April 2014 16:55:30 Ritesh Harjani wrote: > >> In explaining the issue below, made a mistake of taking PAGE_SIZE > >> instead of PAGE_SHIFT (mistake mentioned inline). > >> Although numerical values and patch is correct. > > > > I was about to send the same patch, so, provided you fix the commit > > message, > > > > Acked-by: Laurent Pinchart > > > >> On Sat, Apr 19, 2014 at 4:49 PM, Ritesh Harjani > >> > >> wrote: > >> > I am finding an oops after following commit. I am on 3.10.30 kernel but > >> > applied all the latest patches from arch/arm/mm/dma-mapping.c > >> > > >> > I added some debug logs to see what is the error, on which I found that > >> > we > >> > are incorrectly setting mapping->size value. > >> > Please take a look at this and correct me if I am wrong here. > >> > > >> > FAULTY COMMIT: > >> > commit 68efd7d2fb32c2606f1da318b6a851 > >> > d933813f27 > >> > Author: Marek Szyprowski > >> > Date: Tue Feb 25 13:01:09 2014 +0100 > >> > > >> > arm: dma-mapping: remove order parameter from > >> > arm_iommu_create_mapping() > >> > > >> > OOPS LOGS: > >> > [26.898145] __alloc_iova#LINE: 1097 start = 0x3500 > >> > [26.898159] __alloc_iova#LINE:1136 iova = 0x53500000 > >> > [26.898170] __alloc_iova#LINE:1138 mapping->base= 0x50000000 > >> > [26.898181] __alloc_iova#LINE:1140 mapping->size = 0x1000000, i = 0 > >> > [26.924442] __free_iova, bitmap_index = 3 > >> > > >> > [Ritesh]: bitmap_index should be 0 for address 0x53500000. see in > >> > alloc_iova above. > >> > > >> > [26.924454] __free_iova,addr = 0x53500000 > >> > [26.924463] __free_iova,mapping->base = 0x50000000 > >> > [26.924472] __free_iova,mapping->size = 0x1000000 > >> > [26.924482] __free_iova,bitmap_base = 0x53000000 > >> > [26.924490] __free_iova, start = 0x500 > >> > > >> > [Ritesh]: start should be 0x3500 for address 0x53500000. see in > >> > alloc_iova > >> > above. > >> > > >> > [26.924533] Unable to handle kernel NULL pointer dereference at virtual > >> > address 000000a0 > >> > [26.924543] pgd = e7a84000 > >> > [26.924558] [000000a0] *pgd=00000000 > >> > [26.924572] Internal error: Oops: 5 [#1] PREEMPT SMP ARM > >> > [26.924598] Modules linked in: > >> > [26.924613] CPU: 1 PID: 2263 Comm: BufferLiberator Not tainted 3.10.30+ > >> > #144 > >> > [26.924624] task: e7370a40 ti: e6e06000 task.ti: e6e06000 > >> > [26.924644] PC is at bitmap_clear+0x48/0xd0 > >> > [26.924659] LR is at __iommu_remove_mapping+0x130/0x164 > >> > [26.924673] pc : [] lr : [] psr: 20000093 > >> > [26.924673] sp : e6e07e20 ip : ffffffff fp : e6e07e3c > >> > [26.924682] r10: 00000500 r9 : c1333ea8 r8 : 80000013 > >> > [26.924692] r7 : ffffffff r6 : 00000321 r5 : 000000a0 r4 : 00000028 > >> > [26.924707] r3 : 00000000 r2 : 00000341 r1 : 00000500 r0 : 00000000 > >> > [26.924730] Flags: nzCv IRQs off FIQs on Mode SVC_32 ISA ARM > >> > Segment > >> > user > >> > [26.924742] Control: 10c5387d Table: 77a8406a DAC: 00000015 > >> > > >> > > >> > See below on how this is wrong: > >> > > >> > here iova_base = 0x50000000 > >> > iova_size = 0x20000000 > >> > => bits needed to map = 131072. > >> > > >> > => bitmap_size = 0x4000 > >> > since bitmap_size > PAGE_SIZE > >> > => bitmap_size = PAGE_SIZE, extensions = 4; > >> > > >> > Now, mapping->size is currently set as bitmap_size << PAGE_SHIFT. > >> > > >> > =>mapping->size = 0x1000000. > >> > > >> > mapping->size is the IOVA size, which one bitmap can address. > >> > > >> > Now mapping->size * extensions should be size (0x20000000). > >> > which is not true, => our bitmap_size is set wrong. > >> > > >> > it should be (mapping->bits << PAGE_SIZE) or say > >> > >> It should be PAGE_SHIFT here. > >> > >> > (BITS_PER_BYTE * bitmap_size << PAGE_SIZE) > >> > >> It should be PAGE_SHIFT here. > >> > >> > => (8 * 0x1000) << 12) = 0x8000000 > >> > > >> > With this IOVA_SIZE = extensions * mapping->size = 0x20000000 > >> > > >> > > >> > > >> > PATCH: > >> > > >> > Currently mapping->size is wrongly set resulting > >> > in OOPS (atleast we see OOPS with extension 4). > >> > > >> > Fix this. > >> > > >> > Signed-off-by: Ritesh Harjani > >> > --- > >> > > >> > arch/arm/mm/dma-mapping.c | 2 +- > >> > 1 file changed, 1 insertion(+), 1 deletion(-) > >> > > >> > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > >> > index f62aa06..d1701a2 100644 > >> > --- a/arch/arm/mm/dma-mapping.c > >> > +++ b/arch/arm/mm/dma-mapping.c > >> > @@ -1963,8 +1963,8 @@ arm_iommu_create_mapping(struct bus_type *bus, > >> > dma_addr_t base, size_t size) > >> > > >> > mapping->nr_bitmaps = 1; > >> > mapping->extensions = extensions; > >> > mapping->base = base; > >> > > >> > - mapping->size = bitmap_size << PAGE_SHIFT; > >> > > >> > mapping->bits = BITS_PER_BYTE * bitmap_size; > >> > > >> > + mapping->size = mapping->bits << PAGE_SHIFT; > >> > > >> > spin_lock_init(&mapping->lock); -- Regards, Laurent Pinchart