| Message ID | 20161010034356.GY19539@ZenIV.linux.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 ]--- -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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)