swiotlb: fix back-off path when memory allocation fails
This fixes a SWIOTLB oops With SWIOTLB being enabled and straight-forward page allocation failure [1], the swiotlb_alloc_coherent fall-back path hits an issue [2], resulting in my webcam failing to work. At the time of oops, RDI is clearly a pointer to a structure which has arrived as NULL, leading to the typo in swiotlb_map_single's callsite arguments. Correctly passing the device structure [3] addresses the issue and gets my webcam working again (the allocation failure still occuring). --- [1] skype: page allocation failure. order:3, mode:0x1 Pid: 5895, comm: skype Not tainted 2.6.27-rc6-235c-debug #1 Call Trace: [<ffffffff802b7cf0>] __alloc_pages_internal+0x4a0/0x5d0 [<ffffffff802d5ddd>] alloc_pages_current+0xad/0x110 [<ffffffff802b4ccd>] __get_free_pages+0x1d/0x60 [<ffffffff8046cd39>] swiotlb_alloc_coherent+0x49/0x180 [<ffffffff80212731>] dma_alloc_coherent+0x281/0x310 [<ffffffff805621c0>] hcd_buffer_alloc+0x50/0x90 [<ffffffff805547fd>] usb_buffer_alloc+0x2d/0x40 [<ffffffffa0056763>] uvc_alloc_urb_buffers+0x53/0xf0 [uvcvideo] [<ffffffffa0056958>] uvc_init_video+0x158/0x3e0 [uvcvideo] [<ffffffffa0056c17>] uvc_video_enable+0x37/0x80 [uvcvideo] [<ffffffffa0055853>] uvc_v4l2_do_ioctl+0x723/0x1260 [uvcvideo] [<ffffffff8026dd61>] ? trace_hardirqs_off_caller+0x21/0xc0 [<ffffffff8026dd61>] ? trace_hardirqs_off_caller+0x21/0xc0 [<ffffffffa0032c9f>] video_usercopy+0x19f/0x390 [videodev] [<ffffffffa0055130>] ? uvc_v4l2_do_ioctl+0x0/0x1260 [uvcvideo] [<ffffffff8026d0ce>] ? put_lock_stats+0xe/0x30 [<ffffffffa0054dad>] uvc_v4l2_ioctl+0x4d/0x80 [uvcvideo] [<ffffffffa0045083>] native_ioctl+0x83/0x90 [compat_ioctl32] [<ffffffffa004534e>] v4l_compat_ioctl32+0x2be/0x1da4 [compat_ioctl32] [<ffffffff806aad21>] ? do_page_fault+0x3d1/0xae0 [<ffffffff80270ccd>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff80270c59>] ? trace_hardirqs_on_caller+0x149/0x1b0 [<ffffffff80270ccd>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff80329afa>] compat_sys_ioctl+0x8a/0x3c0 [<ffffffff806a700d>] ? trace_hardirqs_off_thunk+0x3a/0x3c [<ffffffff8022f816>] sysenter_dispatch+0x7/0x2c [<ffffffff806a6fce>] ? trace_hardirqs_on_thunk+0x3a/0x3f Mem-Info: Node 0 DMA per-cpu: CPU 0: hi: 0, btch: 1 usd: 0 CPU 1: hi: 0, btch: 1 usd: 0 Node 0 DMA32 per-cpu: CPU 0: hi: 186, btch: 31 usd: 3 CPU 1: hi: 186, btch: 31 usd: 0 Node 0 Normal per-cpu: CPU 0: hi: 186, btch: 31 usd: 23 CPU 1: hi: 186, btch: 31 usd: 179 Active:78545 inactive:48683 dirty:31 writeback:0 unstable:2 free:830202 slab:17516 mapped:17473 pagetables:3496 bounce:0 Node 0 DMA free:36kB min:28kB low:32kB high:40kB active:0kB inactive:0kB present:15156kB pages_scanned:0 all_unreclaimable? no lowmem_reserve[]: 0 3207 3956 3956 Node 0 DMA32 free:3197192kB min:6512kB low:8140kB high:9768kB active:0kB inactive:0kB present:3284896kB pages_scanned:0 all_unreclaimable? no lowmem_reserve[]: 0 0 748 748 Node 0 Normal free:123580kB min:1516kB low:1892kB high:2272kB active:314180kB inactive:194732kB present:766464kB pages_scanned:0 all_unreclaimable? no lowmem_reserve[]: 0 0 0 0 Node 0 DMA: 1*4kB 0*8kB 0*16kB 1*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 36kB Node 0 DMA32: 4*4kB 3*8kB 2*16kB 3*32kB 4*64kB 5*128kB 3*256kB 5*512kB 4*1024kB 5*2048kB 776*4096kB = 3197224kB Node 0 Normal: 14*4kB 14*8kB 8*16kB 6*32kB 1*64kB 3*128kB 3*256kB 2*512kB 4*1024kB 1*2048kB 28*4096kB = 123560kB 64847 total pagecache pages 0 pages in swap cache Swap cache stats: add 0, delete 0, find 0/0 Free swap = 502752kB Total swap = 502752kB 1048576 pages RAM 52120 pages reserved 71967 pages shared 143004 pages non-shared --- [2] BUG: unable to handle kernel NULL pointer dereference at 00000000000002c8 IP: [<ffffffff8046c84c>] map_single+0x1c/0x280 PGD 10e54e067 PUD 10e595067 PMD 0 Oops: 0000 [1] PREEMPT SMP DEBUG_PAGEALLOC CPU 0 Modules linked in: kvm_intel kvm microcode uvcvideo compat_ioctl32 videodev v4l1_compat shpchp pci_hotplug Pid: 5895, comm: skype Not tainted 2.6.27-rc6-235c-debug #1 RIP: 0010:[<ffffffff8046c84c>] [<ffffffff8046c84c>] map_single+0x1c/0x280 RSP: 0018:ffff88010e78d988 EFLAGS: 00210296 RAX: 0000780000000000 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000005000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88010e78d9e8 R08: 0000000000000000 R09: 0000000000000001 R10: ffff88010e78d698 R11: 0000000000000001 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000005000 R15: ffff88012f1c9968 FS: 0000000000000000(0000) GS:ffffffff80a6cdc0(0063) knlGS:00000000f6355b90 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000000002c8 CR3: 000000010e57d000 CR4: 00000000000026e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process skype (pid: 5895, threadinfo ffff88010e78c000, task ffff88012b9cc460) Stack: 0000000200000000 0000000000005000 0000000000000000 0000000000000000 00000000000017b8 0000000000000000 ffff88010e78d9c8 0000000000000000 0000000000000002 0000000000000000 0000000000005000 ffff88012f1c9968 Call Trace: [<ffffffff8046cbb0>] swiotlb_map_single_attrs+0x60/0xf0 [<ffffffff8046cc4c>] swiotlb_map_single+0xc/0x10 [<ffffffff8046cdee>] swiotlb_alloc_coherent+0xfe/0x180 [<ffffffff80212731>] dma_alloc_coherent+0x281/0x310 [<ffffffff805621c0>] hcd_buffer_alloc+0x50/0x90 [<ffffffff805547fd>] usb_buffer_alloc+0x2d/0x40 [<ffffffffa0056763>] uvc_alloc_urb_buffers+0x53/0xf0 [uvcvideo] [<ffffffffa0056958>] uvc_init_video+0x158/0x3e0 [uvcvideo] [<ffffffffa0056c17>] uvc_video_enable+0x37/0x80 [uvcvideo] [<ffffffffa0055853>] uvc_v4l2_do_ioctl+0x723/0x1260 [uvcvideo] [<ffffffff8026dd61>] ? trace_hardirqs_off_caller+0x21/0xc0 [<ffffffff8026dd61>] ? trace_hardirqs_off_caller+0x21/0xc0 [<ffffffffa0032c9f>] video_usercopy+0x19f/0x390 [videodev] [<ffffffffa0055130>] ? uvc_v4l2_do_ioctl+0x0/0x1260 [uvcvideo] [<ffffffff8026d0ce>] ? put_lock_stats+0xe/0x30 [<ffffffffa0054dad>] uvc_v4l2_ioctl+0x4d/0x80 [uvcvideo] [<ffffffffa0045083>] native_ioctl+0x83/0x90 [compat_ioctl32] [<ffffffffa004534e>] v4l_compat_ioctl32+0x2be/0x1da4 [compat_ioctl32] [<ffffffff806aad21>] ? do_page_fault+0x3d1/0xae0 [<ffffffff80270ccd>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff80270c59>] ? trace_hardirqs_on_caller+0x149/0x1b0 [<ffffffff80270ccd>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff80329afa>] compat_sys_ioctl+0x8a/0x3c0 [<ffffffff806a700d>] ? trace_hardirqs_off_thunk+0x3a/0x3c [<ffffffff8022f816>] sysenter_dispatch+0x7/0x2c [<ffffffff806a6fce>] ? trace_hardirqs_on_thunk+0x3a/0x3f Code: 45 31 c0 48 89 e5 e8 a4 ff ff ff c9 c3 66 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 ec 38 48 89 75 b0 48 89 55 a8 89 4d a4 <48> 8b 87 c8 02 00 00 48 85 c0 0f 84 1c 02 00 00 48 8b 58 08 48 RIP [<ffffffff8046c84c>] map_single+0x1c/0x280 RSP <ffff88010e78d988> CR2: 00000000000002c8 ---[ end trace 5d15baeeb7025a0e ]--- --- [3] ffffffff8046c830 <map_single>: map_single(): /store/kernel/linux/lib/swiotlb.c:291 ffffffff8046c830: 55 push %rbp ffffffff8046c831: 48 89 e5 mov %rsp,%rbp ffffffff8046c834: 41 57 push %r15 ffffffff8046c836: 41 56 push %r14 ffffffff8046c838: 41 55 push %r13 ffffffff8046c83a: 41 54 push %r12 ffffffff8046c83c: 53 push %rbx ffffffff8046c83d: 48 83 ec 38 sub $0x38,%rsp ffffffff8046c841: 48 89 75 b0 mov %rsi,-0x50(%rbp) ffffffff8046c845: 48 89 55 a8 mov %rdx,-0x58(%rbp) ffffffff8046c849: 89 4d a4 mov %ecx,-0x5c(%rbp) dma_get_seg_boundary(): /store/kernel/linux/include/linux/dma-mapping.h:80 ffffffff8046c84c: 48 8b 87 c8 02 00 00 mov 0x2c8(%rdi),%rax <---- --- [4] Signed-off-by:Daniel J Blueman <daniel.blueman@gmail.com> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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