Messages in this thread |  | | Date | Mon, 10 Oct 2016 09:11:22 -0400 | From | Dave Jones <> | Subject | Re: btrfs_direct_IO oops |
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On Mon, Oct 10, 2016 at 04:43:57AM +0100, Al Viro wrote:
> Very interesting. Could you slap something like > diff --git a/lib/iov_iter.c b/lib/iov_iter.c > index 0ce3411..1ef00e7 100644 > --- a/lib/iov_iter.c > +++ b/lib/iov_iter.c > @@ -682,8 +682,9 @@ static void pipe_advance(struct iov_iter *i, size_t size) > { > struct pipe_inode_info *pipe = i->pipe; > struct pipe_buffer *buf; > - int idx = i->idx; > - size_t off = i->iov_offset; > + int old_idx = idx = i->idx; > + size_t old_off = off = i->iov_offset; > + size_t old_size = size; > > if (unlikely(i->count < size)) > size = i->count; > @@ -713,6 +714,9 @@ static void pipe_advance(struct iov_iter *i, size_t size) > pipe->nrbufs--; > } > } > + if (!sanity(i)) > + printk(KERN_ERR "buggered pipe_advance(%zd) [%d,%zd]", > + old_size, old_idx, old_off); > } > > void iov_iter_advance(struct iov_iter *i, size_t size) > > in there and try to reproduce that one?
My compiler choked on that, but I fixed it up. The printk didn't trigger though..
idx = 0, offset = 0 curbuf = 0, nrbufs = 1, buffers = 16 [ffffffffb9a21100 ffffea00126019c0 0 4096] [ (null) ffffea0013746440 0 0] [ (null) ffffea00132956c0 0 0] [ (null) ffffea0013295700 0 0] [ (null) ffffea0013295740 0 0] [ (null) ffffea0013295780 0 0] [ (null) ffffea00132957c0 0 0] [ (null) ffffea0013595c00 0 0] [ (null) ffffea0012b1b6c0 0 0] [ (null) (null) 0 0] [ (null) (null) 0 0] [ (null) (null) 0 0] [ (null) (null) 0 0] [ (null) (null) 0 0] [ (null) (null) 0 0] [ (null) (null) 0 0] ------------[ cut here ]------------ WARNING: CPU: 1 PID: 13581 at lib/iov_iter.c:327 sanity+0x102/0x150 CPU: 1 PID: 13581 Comm: trinity-c17 Not tainted 4.8.0-think+ #9 ffffc90000963ae8 ffffffffb93e22d1 0000000000000000 0000000000000000
ffffffffb9c1e1cb ffffffffb93fa5b2 ffffc90000963b28 ffffffffb908b010
00000147d43c0e7f ffffffffb9c1e1cb 0000000000000147 0000000000000010
Call Trace: [<ffffffffb93e22d1>] dump_stack+0x6c/0x9b [<ffffffffb93fa5b2>] ? sanity+0x102/0x150 [<ffffffffb908b010>] __warn+0x110/0x130 [<ffffffffb908b19c>] warn_slowpath_null+0x2c/0x40 [<ffffffffb93fa5b2>] sanity+0x102/0x150 [<ffffffffb93fe94e>] copy_page_to_iter+0x2be/0x480 [<ffffffffb91cc8b1>] ? workingset_activation+0xc1/0x120 [<ffffffffb91cc7f0>] ? workingset_refault+0x190/0x190 [<ffffffffb9195b85>] generic_file_read_iter+0x245/0xd30 [<ffffffffb92764ed>] generic_file_splice_read+0xfd/0x230 [<ffffffffb92763f0>] ? pipe_to_user+0x40/0x40 [<ffffffffb9275f08>] do_splice_to+0x98/0xd0 [<ffffffffb9276014>] splice_direct_to_actor+0xd4/0x2c0 [<ffffffffb9275660>] ? generic_pipe_buf_nosteal+0x10/0x10 [<ffffffffb92762c5>] do_splice_direct+0xc5/0x110 [<ffffffffb92381c2>] do_sendfile+0x242/0x470 [<ffffffffb923929d>] SyS_sendfile64+0x7d/0xf0 [<ffffffffb900279f>] do_syscall_64+0x7f/0x200 [<ffffffffb99de8cb>] entry_SYSCALL64_slow_path+0x25/0x25 ---[ end trace 6773f425063b7f84 ]---
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