udmabuf: Set the DMA mask for the udmabuf device (v2)

commit 9e9fa6a9198b767b00f48160800128e83a038f9f upstream.

If the DMA mask is not set explicitly, the following warning occurs
when the userspace tries to access the dma-buf via the CPU as
reported by syzbot here:

WARNING: CPU: 1 PID: 3595 at kernel/dma/mapping.c:188
__dma_map_sg_attrs+0x181/0x1f0 kernel/dma/mapping.c:188
Modules linked in:
CPU: 0 PID: 3595 Comm: syz-executor249 Not tainted
5.17.0-rc2-syzkaller-00316-g0457e5153e0e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:__dma_map_sg_attrs+0x181/0x1f0 kernel/dma/mapping.c:188
Code: 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 71 4c 8b 3d c0
83 b5 0d e9 db fe ff ff e8 b6 0f 13 00 0f 0b e8 af 0f 13 00 <0f> 0b 45
   31 e4 e9 54 ff ff ff e8 a0 0f 13 00 49 8d 7f 50 48 b8 00
RSP: 0018:ffffc90002a07d68 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88807e25e2c0 RSI: ffffffff81649e91 RDI: ffff88801b848408
RBP: ffff88801b848000 R08: 0000000000000002 R09: ffff88801d86c74f
R10: ffffffff81649d72 R11: 0000000000000001 R12: 0000000000000002
R13: ffff88801d86c680 R14: 0000000000000001 R15: 0000000000000000
FS:  0000555556e30300(0000) GS:ffff8880b9d00000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000200000cc CR3: 000000001d74a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 dma_map_sgtable+0x70/0xf0 kernel/dma/mapping.c:264
 get_sg_table.isra.0+0xe0/0x160 drivers/dma-buf/udmabuf.c:72
 begin_cpu_udmabuf+0x130/0x1d0 drivers/dma-buf/udmabuf.c:126
 dma_buf_begin_cpu_access+0xfd/0x1d0 drivers/dma-buf/dma-buf.c:1164
 dma_buf_ioctl+0x259/0x2b0 drivers/dma-buf/dma-buf.c:363
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f62fcf530f9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89
f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01
f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe3edab9b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f62fcf530f9
RDX: 0000000020000200 RSI: 0000000040086200 RDI: 0000000000000006
RBP: 00007f62fcf170e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f62fcf17170
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

v2: Dont't forget to deregister if DMA mask setup fails.

Reported-by: syzbot+10e27961f4da37c443b2@syzkaller.appspotmail.com
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20220520205235.3687336-1-vivek.kasireddy@intel.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 9631f2fd2faf7f2d575c2fae4872e7eccecad722..38e8767ec371531695a8aed5fd77c26099389ce2 100644 (file)
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -368,7 +368,23 @@ static struct miscdevice udmabuf_misc = {
 
 static int __init udmabuf_dev_init(void)
 {
-       return misc_register(&udmabuf_misc);
+       int ret;
+
+       ret = misc_register(&udmabuf_misc);
+       if (ret < 0) {
+               pr_err("Could not initialize udmabuf device\n");
+               return ret;
+       }
+
+       ret = dma_coerce_mask_and_coherent(udmabuf_misc.this_device,
+                                          DMA_BIT_MASK(64));
+       if (ret < 0) {
+               pr_err("Could not setup DMA mask for udmabuf device\n");
+               misc_deregister(&udmabuf_misc);
+               return ret;
+       }
+
+       return 0;
 }
 
 static void __exit udmabuf_dev_exit(void)