There were three possibly related fixes - one that went in after rc1,
and two marked for stable that Long Li did that were in linux-next
(and will be back in linux-next builds in a few days)
On Fri, Dec 14, 2018 at 2:13 AM Murphy Zhou <jencce.kernel@xxxxxxxxx> wrote:
>
> Hi,
>
> It seems that there is a problem in the new dio functions.
>
> Direct IO on cifs mount is blocking on read since v4.20-rc1. It was ok on v4.19.
>
> Bisect points to commit:
> be4eb68 CIFS: Add direct I/O functions to file_operations
>
> With this commit reverted on 4.20-rc1, test is not blocking any more.
>
> This is easily reproducible by LTP diotest4 on cifs mount, from v4.20-rc1 until
> latest Linus tree. Ctrl-C can interrupt the blocking process.
>
> Sorry for the late report,
> Murphy
>
> # gdb says it's blocking on open
> diotest4 18 TFAIL : diotest4.c:180: read, write with non-aligned buffer
> 458 close(fd);
> (gdb)
> 465 if ((fd = open(filename, O_DIRECT | O_RDWR)) < 0) {
> (gdb)
> 469 if (lseek(fd, offset, SEEK_SET) < 0) {
> (gdb)
> 474 errno = 0;
> (gdb)
> 475 ret = read(fd, (char *)((ulong) ADDRESS_OF_MAIN & pagemask),
> (gdb)
>
> # steps to reproduce
> git clone https://github.com/linux-test-project/ltp.git
> cd ltp
> make autotools
> ./configure
> make
> TMPDIR=/cifsmnt ./testcases/kernel/io/direct_io/diotest4
>
> /cifsmnt is the cifs mountpoint.
>
> # dmesg
> [ 234.469584] CPU: 1 PID: 1876 Comm: diotest4 Not tainted 4.20.0-rc1-6510223 #1
> [ 234.469807] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
> [ 234.470026] Call Trace:
> [ 234.470361] dump_stack+0x46/0x60
> [ 234.470710] cifs_send_async_read.isra.47.cold.62+0x22/0x27 [cifs]
> [ 234.470983] __cifs_readv+0x169/0x360 [cifs]
> [ 234.471292] __vfs_read+0x12e/0x190
> [ 234.471513] vfs_read+0x85/0x130
> [ 234.471699] ksys_read+0x4a/0xb0
> [ 234.471939] do_syscall_64+0x50/0x190
> [ 234.472200] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> [ 234.472435] RIP: 0033:0x7fefecddeb52
> [ 234.472630] Code: 94 20 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b6 0f 1f 80 00 00 00 00 f3 0f 1e fa 8b 05 f6 d8 20 00 85 c0 75 12 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 56 c3 0f 1f 44 00 00 41 54 49 89 d4 55 48 89
> [ 234.473075] RSP: 002b:00007ffe0bbe51f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> [ 234.473319] RAX: ffffffffffffffda RBX: 0000000000000fff RCX: 00007fefecddeb52
> [ 234.473529] RDX: 0000000000001000 RSI: 00007fefeca2c000 RDI: 0000000000000006
> [ 234.473738] RBP: 00000000fffff000 R08: 0000000000411b4f R09: 00000000fe534d42
> [ 234.473959] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fefed2046c0
> [ 234.474180] R13: 0000000000b9a000 R14: fffffffffffff000 R15: 00007ffe0bbe5228
>
> # ps
> 1871 1876 1876 1624 pts/0 1646 D 0 0:00 \_ diotest4
>
> # mount.cifs -V
> mount.cifs version: 6.8
>
> # mount | grep cifs
> //localhost/test on /cifsmnt type cifs (rw,relatime,vers=3.1.1,cache=strict,username=root,uid=0,noforceuid,gid=0,noforcegid,addr=0000:0000:0000:0000:0000:0000:0000:0001,file_mode=0755,dir_mode=0755,soft,nounix,serverino,mapposix,sfu,mfsymlinks,rsize=4194304,wsize=4194304,echo_interval=60,actimeo=1)
>
> # cat /etc/samba/smb.conf
> [test]
> path = /export/cifstest
> writeable = yes
>
> # smbd -V
> Version 4.9.1
--
Thanks,
Steve
