From: Dave Jones <davej@codemonkey.org.uk>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: iov_iter_pipe warning.
Date: Tue, 11 Apr 2017 20:58:53 -0400 [thread overview]
Message-ID: <20170412005853.vqyuo6722tmthn5u@codemonkey.org.uk> (raw)
In-Reply-To: <20170412001746.GM29622@ZenIV.linux.org.uk>
On Wed, Apr 12, 2017 at 01:17:46AM +0100, Al Viro wrote:
> On Tue, Apr 11, 2017 at 08:06:07PM -0400, Dave Jones wrote:
> > On Wed, Apr 12, 2017 at 12:56:41AM +0100, Al Viro wrote:
> > > On Wed, Apr 12, 2017 at 12:51:58AM +0100, Al Viro wrote:
> > > > On Tue, Apr 11, 2017 at 07:45:58PM -0400, Dave Jones wrote:
> > > > > > if (file->f_op->splice_write == generic_splice_sendpage) {
> > > > > > struct socket *sock = file->private_data;
> > > > > > printk(KERN_ERR "socket [%d, %p]\n", sock->type, sock->ops);
> > > > > > }
> > > > > > printk(KERN_ERR "in->f_op = %p\n", in->f_op);
> > > > >
> > > > > Ugh, this explodes with a million errors when I try to compile it.
> > > > > It misses socket definition, and include <linux/net.h> causes another
> > > > > cascade of errors about linkage.h and nonsense.
> > > >
> > > > Ignore the socket part - you've already triggered it with NFS file as
> > > > destination, so this is not particularly interesting. I would still like
> > > > to see in->f_op and even more - the checks in default_file_splice_read().
> > >
> > > ... and the latter had a braino - WARN_ON(size != ret), not len != ret.
> > > Diff follows:
> >
> > super fast repro..
>
> Alas, that's just another braino - it checks for non-zero ->buffers (always
> true) rather than non-zero ->nrbufs (non-empty pipe). Sorry. Fixed diff
> follows:
[ 462.415864] WARNING: CPU: 0 PID: 21500 at fs/splice.c:985 splice_direct_to_actor+0x13f/0x280
[ 462.428443] CPU: 0 PID: 21500 Comm: trinity-c4 Not tainted 4.11.0-rc6-think+ #10
[ 462.453818] Call Trace:
[ 462.466415] dump_stack+0x68/0x93
[ 462.478920] __warn+0xcb/0xf0
[ 462.491367] warn_slowpath_null+0x1d/0x20
[ 462.503823] splice_direct_to_actor+0x13f/0x280
[ 462.516236] ? generic_pipe_buf_nosteal+0x10/0x10
[ 462.528606] do_splice_direct+0x9e/0xd0
[ 462.540825] do_sendfile+0x1d7/0x3c0
[ 462.552910] SyS_sendfile64+0x73/0xe0
[ 462.564989] do_syscall_64+0x66/0x1d0
[ 462.576949] entry_SYSCALL64_slow_path+0x25/0x25
[ 462.588872] RIP: 0033:0x7febc78b30f9
[ 462.600809] RSP: 002b:00007ffd767b6398 EFLAGS: 00000246
[ 462.612790] ORIG_RAX: 0000000000000028
[ 462.624684] RAX: ffffffffffffffda RBX: 0000000000000028 RCX: 00007febc78b30f9
[ 462.636737] RDX: 00007febc5c1e000 RSI: 0000000000000130 RDI: 0000000000000130
[ 462.648756] RBP: 00007febc7f66000 R08: 0000000000000ff1 R09: fffffffffffffffd
[ 462.660709] R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000002
[ 462.672627] R13: 00007febc7f66048 R14: 00007febc7f89ad8 R15: 00007febc7f66000
[ 462.684586] ---[ end trace d002d06d5879c8a9 ]---
[ 462.696557] in->f_op = ffffffffa02df980, ->splice_write = ffffffff812b2b20
$ grep ffffffffa02df980 /proc/kallsyms
ffffffffa02df980 r nfs4_file_operations [nfsv4]
$ grep ffffffff812b2b20 /proc/kallsyms
ffffffff812b2b20 T iter_file_splice_write
next prev parent reply other threads:[~2017-04-12 0:58 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-21 20:59 iov_iter_pipe warning Dave Jones
2017-04-05 22:02 ` Dave Jones
2017-04-10 19:28 ` Al Viro
2017-04-10 19:42 ` Dave Jones
2017-04-10 19:57 ` Al Viro
2017-04-10 23:48 ` Dave Jones
2017-04-11 0:22 ` Al Viro
2017-04-11 3:05 ` Dave Jones
2017-04-11 3:28 ` Al Viro
2017-04-11 20:53 ` Dave Jones
2017-04-11 21:12 ` Al Viro
2017-04-11 22:25 ` Dave Jones
2017-04-11 23:28 ` Al Viro
2017-04-11 23:34 ` Dave Jones
2017-04-11 23:48 ` Al Viro
2017-04-11 23:45 ` Dave Jones
2017-04-11 23:51 ` Al Viro
2017-04-11 23:56 ` Al Viro
2017-04-12 0:06 ` Dave Jones
2017-04-12 0:17 ` Al Viro
2017-04-12 0:58 ` Dave Jones [this message]
2017-04-12 1:15 ` Al Viro
2017-04-12 2:29 ` Dave Jones
2017-04-12 2:58 ` Al Viro
2017-04-12 14:35 ` Dave Jones
2017-04-12 15:26 ` Al Viro
2017-04-12 16:27 ` Dave Jones
2017-04-12 17:07 ` Al Viro
2017-04-12 19:03 ` Dave Jones
2017-04-21 17:54 ` Al Viro
2017-04-27 4:19 ` Dave Jones
2017-04-27 16:34 ` Dave Jones
2017-04-27 17:39 ` Al Viro
2017-04-28 15:29 ` Dave Jones
2017-04-28 16:43 ` Al Viro
2017-04-28 16:50 ` Dave Jones
2017-04-28 17:20 ` Al Viro
2017-04-28 18:25 ` Al Viro
2017-04-29 1:58 ` Dave Jones
2017-04-29 2:47 ` Al Viro
2017-04-29 15:51 ` Dave Jones
2017-04-29 20:46 ` [git pull] vfs.git fix (Re: iov_iter_pipe warning.) Al Viro
2017-08-07 20:18 ` iov_iter_pipe warning Dave Jones
2017-08-28 20:31 ` Dave Jones
2017-08-29 4:25 ` Darrick J. Wong
2017-08-30 17:05 ` Dave Jones
2017-08-30 17:13 ` Darrick J. Wong
2017-08-30 17:17 ` Dave Jones
2017-09-06 20:03 ` Dave Jones
2017-09-06 23:46 ` Dave Chinner
2017-09-07 3:48 ` Dave Jones
2017-09-07 4:33 ` Al Viro
2017-09-08 1:04 ` Al Viro
2017-09-10 1:07 ` Dave Jones
2017-09-10 2:57 ` Al Viro
2017-09-10 16:07 ` Dave Jones
2017-09-10 20:05 ` Al Viro
2017-09-10 20:07 ` Dave Jones
2017-09-10 20:33 ` Al Viro
2017-09-10 21:11 ` Dave Chinner
2017-09-10 21:19 ` Al Viro
2017-09-10 22:08 ` Dave Chinner
2017-09-10 23:07 ` Al Viro
2017-09-10 23:15 ` Al Viro
2017-09-11 0:31 ` Dave Chinner
2017-09-11 3:32 ` Al Viro
2017-09-11 6:44 ` Dave Chinner
2017-09-11 20:07 ` Al Viro
2017-09-11 20:17 ` Al Viro
2017-09-12 6:02 ` Dave Chinner
2017-09-12 11:13 ` Al Viro
2017-09-11 12:07 ` Christoph Hellwig
2017-09-11 12:51 ` Al Viro
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