* [PATCH 1/2] splice: don't merge into linked buffers
@ 2018-10-15 15:04 Jann Horn
2018-10-15 15:04 ` [PATCH 2/2] pipe: remove ->can_merge from pipe_buf_operations Jann Horn
2018-10-15 21:00 ` [PATCH 1/2] splice: don't merge into linked buffers Eric Biggers
0 siblings, 2 replies; 4+ messages in thread
From: Jann Horn @ 2018-10-15 15:04 UTC (permalink / raw)
To: Al Viro, Miklos Szeredi, Jens Axboe, Jens Axboe, jannh
Cc: linux-kernel, linux-fsdevel, Kees Cook, Eric Biggers
Before this patch, it was possible for two pipes to affect each other after
data had been transferred between them with tee():
============
$ cat tee_test.c
int main(void) {
int pipe_a[2];
if (pipe(pipe_a)) err(1, "pipe");
int pipe_b[2];
if (pipe(pipe_b)) err(1, "pipe");
if (write(pipe_a[1], "abcd", 4) != 4) err(1, "write");
if (tee(pipe_a[0], pipe_b[1], 2, 0) != 2) err(1, "tee");
if (write(pipe_b[1], "xx", 2) != 2) err(1, "write");
char buf[5];
if (read(pipe_a[0], buf, 4) != 4) err(1, "read");
buf[4] = 0;
printf("got back: '%s'\n", buf);
}
$ gcc -o tee_test tee_test.c
$ ./tee_test
got back: 'abxx'
$
============
Fix it by explicitly marking buffers as mergeable and clearing that flag in
splice_pipe_to_pipe() and link_pipe().
Cc: <stable@vger.kernel.org>
Fixes: 7c77f0b3f920 ("splice: implement pipe to pipe splicing")
Fixes: 70524490ee2e ("[PATCH] splice: add support for sys_tee()")
Signed-off-by: Jann Horn <jannh@google.com>
---
Cleanup in the next patch, to simplify backporting.
fs/pipe.c | 5 +++--
fs/splice.c | 6 ++++++
include/linux/pipe_fs_i.h | 8 ++++++++
3 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/fs/pipe.c b/fs/pipe.c
index bdc5d3c0977d..4e2eee77f855 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -379,7 +379,8 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
struct pipe_buffer *buf = pipe->bufs + lastbuf;
int offset = buf->offset + buf->len;
- if (buf->ops->can_merge && offset + chars <= PAGE_SIZE) {
+ if (buf->ops->can_merge && offset + chars <= PAGE_SIZE &&
+ (buf->flags & PIPE_BUF_FLAG_MAYMERGE)) {
ret = pipe_buf_confirm(pipe, buf);
if (ret)
goto out;
@@ -439,7 +440,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
buf->ops = &anon_pipe_buf_ops;
buf->offset = 0;
buf->len = copied;
- buf->flags = 0;
+ buf->flags = PIPE_BUF_FLAG_MAYMERGE;
if (is_packetized(filp)) {
buf->ops = &packet_pipe_buf_ops;
buf->flags = PIPE_BUF_FLAG_PACKET;
diff --git a/fs/splice.c b/fs/splice.c
index b3daa971f597..111977c80dfd 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1593,6 +1593,9 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
*/
obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
+ /* We can't merge data into a buffer we don't own. */
+ obuf->flags &= ~PIPE_BUF_FLAG_MAYMERGE;
+
obuf->len = len;
opipe->nrbufs++;
ibuf->offset += obuf->len;
@@ -1667,6 +1670,9 @@ static int link_pipe(struct pipe_inode_info *ipipe,
*/
obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
+ /* We can't merge data into a buffer we don't own. */
+ obuf->flags &= ~PIPE_BUF_FLAG_MAYMERGE;
+
if (obuf->len > len)
obuf->len = len;
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 5a3bb3b7c9ad..8893711f9171 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -8,6 +8,14 @@
#define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */
#define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */
#define PIPE_BUF_FLAG_PACKET 0x08 /* read() as a packet */
+/*
+ * Set this flag if the generic pipe read/write may coalesce data into an
+ * existing buffer. If this is not set, a new pipe page segment is always used
+ * for new data.
+ * When pipe data is copied by reference (as in the tee() syscall), this flag
+ * must be cleared on the copy.
+ */
+#define PIPE_BUF_FLAG_MAYMERGE 0x10
/**
* struct pipe_buffer - a linux kernel pipe buffer
--
2.19.0.605.g01d371f741-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 2/2] pipe: remove ->can_merge from pipe_buf_operations
2018-10-15 15:04 [PATCH 1/2] splice: don't merge into linked buffers Jann Horn
@ 2018-10-15 15:04 ` Jann Horn
2018-10-15 21:00 ` [PATCH 1/2] splice: don't merge into linked buffers Eric Biggers
1 sibling, 0 replies; 4+ messages in thread
From: Jann Horn @ 2018-10-15 15:04 UTC (permalink / raw)
To: Al Viro, Miklos Szeredi, Jens Axboe, Jens Axboe, jannh
Cc: linux-kernel, linux-fsdevel, Kees Cook, Eric Biggers
My last commit "splice: don't merge into linked buffers" made the
"can_merge" field in struct pipe_buf_operations redundant: Whether a buffer
is mergeable is now a property of the buffer, not of the operations struct.
Get rid of it.
Signed-off-by: Jann Horn <jannh@google.com>
---
fs/pipe.c | 4 +---
fs/splice.c | 4 ----
include/linux/pipe_fs_i.h | 7 -------
kernel/relay.c | 1 -
kernel/trace/trace.c | 2 --
net/smc/smc_rx.c | 1 -
6 files changed, 1 insertion(+), 18 deletions(-)
diff --git a/fs/pipe.c b/fs/pipe.c
index 4e2eee77f855..b1ad3271c175 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -227,7 +227,6 @@ void generic_pipe_buf_release(struct pipe_inode_info *pipe,
EXPORT_SYMBOL(generic_pipe_buf_release);
static const struct pipe_buf_operations anon_pipe_buf_ops = {
- .can_merge = 1,
.confirm = generic_pipe_buf_confirm,
.release = anon_pipe_buf_release,
.steal = anon_pipe_buf_steal,
@@ -235,7 +234,6 @@ static const struct pipe_buf_operations anon_pipe_buf_ops = {
};
static const struct pipe_buf_operations packet_pipe_buf_ops = {
- .can_merge = 0,
.confirm = generic_pipe_buf_confirm,
.release = anon_pipe_buf_release,
.steal = anon_pipe_buf_steal,
@@ -379,7 +377,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
struct pipe_buffer *buf = pipe->bufs + lastbuf;
int offset = buf->offset + buf->len;
- if (buf->ops->can_merge && offset + chars <= PAGE_SIZE &&
+ if (offset + chars <= PAGE_SIZE &&
(buf->flags & PIPE_BUF_FLAG_MAYMERGE)) {
ret = pipe_buf_confirm(pipe, buf);
if (ret)
diff --git a/fs/splice.c b/fs/splice.c
index 111977c80dfd..fb7412b2eadb 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -138,7 +138,6 @@ static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe,
}
const struct pipe_buf_operations page_cache_pipe_buf_ops = {
- .can_merge = 0,
.confirm = page_cache_pipe_buf_confirm,
.release = page_cache_pipe_buf_release,
.steal = page_cache_pipe_buf_steal,
@@ -156,7 +155,6 @@ static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,
}
static const struct pipe_buf_operations user_page_pipe_buf_ops = {
- .can_merge = 0,
.confirm = generic_pipe_buf_confirm,
.release = page_cache_pipe_buf_release,
.steal = user_page_pipe_buf_steal,
@@ -326,7 +324,6 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
EXPORT_SYMBOL(generic_file_splice_read);
const struct pipe_buf_operations default_pipe_buf_ops = {
- .can_merge = 0,
.confirm = generic_pipe_buf_confirm,
.release = generic_pipe_buf_release,
.steal = generic_pipe_buf_steal,
@@ -341,7 +338,6 @@ static int generic_pipe_buf_nosteal(struct pipe_inode_info *pipe,
/* Pipe buffer operations for a socket and similar. */
const struct pipe_buf_operations nosteal_pipe_buf_ops = {
- .can_merge = 0,
.confirm = generic_pipe_buf_confirm,
.release = generic_pipe_buf_release,
.steal = generic_pipe_buf_nosteal,
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 8893711f9171..03d3529c7654 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -81,13 +81,6 @@ struct pipe_inode_info {
* in fs/pipe.c for the pipe and generic variants of these hooks.
*/
struct pipe_buf_operations {
- /*
- * This is set to 1, if the generic pipe read/write may coalesce
- * data into an existing buffer. If this is set to 0, a new pipe
- * page segment is always used for new data.
- */
- int can_merge;
-
/*
* ->confirm() verifies that the data in the pipe buffer is there
* and that the contents are good. If the pages in the pipe belong
diff --git a/kernel/relay.c b/kernel/relay.c
index 04f248644e06..db3e419c25a6 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -1175,7 +1175,6 @@ static void relay_pipe_buf_release(struct pipe_inode_info *pipe,
}
static const struct pipe_buf_operations relay_pipe_buf_ops = {
- .can_merge = 0,
.confirm = generic_pipe_buf_confirm,
.release = relay_pipe_buf_release,
.steal = generic_pipe_buf_steal,
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index bf6f1d70484d..820eff45e907 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5803,7 +5803,6 @@ static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
}
static const struct pipe_buf_operations tracing_pipe_buf_ops = {
- .can_merge = 0,
.confirm = generic_pipe_buf_confirm,
.release = generic_pipe_buf_release,
.steal = generic_pipe_buf_steal,
@@ -6823,7 +6822,6 @@ static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
/* Pipe buffer operations for a buffer. */
static const struct pipe_buf_operations buffer_pipe_buf_ops = {
- .can_merge = 0,
.confirm = generic_pipe_buf_confirm,
.release = buffer_pipe_buf_release,
.steal = generic_pipe_buf_steal,
diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
index bbcf0fe4ae10..413a6abf227e 100644
--- a/net/smc/smc_rx.c
+++ b/net/smc/smc_rx.c
@@ -136,7 +136,6 @@ static int smc_rx_pipe_buf_nosteal(struct pipe_inode_info *pipe,
}
static const struct pipe_buf_operations smc_pipe_ops = {
- .can_merge = 0,
.confirm = generic_pipe_buf_confirm,
.release = smc_rx_pipe_buf_release,
.steal = smc_rx_pipe_buf_nosteal,
--
2.19.0.605.g01d371f741-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] splice: don't merge into linked buffers
2018-10-15 15:04 [PATCH 1/2] splice: don't merge into linked buffers Jann Horn
2018-10-15 15:04 ` [PATCH 2/2] pipe: remove ->can_merge from pipe_buf_operations Jann Horn
@ 2018-10-15 21:00 ` Eric Biggers
2018-10-15 21:13 ` Jann Horn
1 sibling, 1 reply; 4+ messages in thread
From: Eric Biggers @ 2018-10-15 21:00 UTC (permalink / raw)
To: Jann Horn
Cc: Al Viro, Miklos Szeredi, Jens Axboe, Jens Axboe, linux-kernel,
linux-fsdevel, Kees Cook
On Mon, Oct 15, 2018 at 05:04:18PM +0200, Jann Horn wrote:
> Before this patch, it was possible for two pipes to affect each other after
> data had been transferred between them with tee():
>
> ============
> $ cat tee_test.c
>
> int main(void) {
> int pipe_a[2];
> if (pipe(pipe_a)) err(1, "pipe");
> int pipe_b[2];
> if (pipe(pipe_b)) err(1, "pipe");
> if (write(pipe_a[1], "abcd", 4) != 4) err(1, "write");
> if (tee(pipe_a[0], pipe_b[1], 2, 0) != 2) err(1, "tee");
> if (write(pipe_b[1], "xx", 2) != 2) err(1, "write");
>
> char buf[5];
> if (read(pipe_a[0], buf, 4) != 4) err(1, "read");
> buf[4] = 0;
> printf("got back: '%s'\n", buf);
> }
> $ gcc -o tee_test tee_test.c
> $ ./tee_test
> got back: 'abxx'
> $
> ============
>
> Fix it by explicitly marking buffers as mergeable and clearing that flag in
> splice_pipe_to_pipe() and link_pipe().
>
> Cc: <stable@vger.kernel.org>
> Fixes: 7c77f0b3f920 ("splice: implement pipe to pipe splicing")
> Fixes: 70524490ee2e ("[PATCH] splice: add support for sys_tee()")
> Signed-off-by: Jann Horn <jannh@google.com>
> ---
> Cleanup in the next patch, to simplify backporting.
>
> fs/pipe.c | 5 +++--
> fs/splice.c | 6 ++++++
> include/linux/pipe_fs_i.h | 8 ++++++++
> 3 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/fs/pipe.c b/fs/pipe.c
> index bdc5d3c0977d..4e2eee77f855 100644
> --- a/fs/pipe.c
> +++ b/fs/pipe.c
> @@ -379,7 +379,8 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
> struct pipe_buffer *buf = pipe->bufs + lastbuf;
> int offset = buf->offset + buf->len;
>
> - if (buf->ops->can_merge && offset + chars <= PAGE_SIZE) {
> + if (buf->ops->can_merge && offset + chars <= PAGE_SIZE &&
> + (buf->flags & PIPE_BUF_FLAG_MAYMERGE)) {
> ret = pipe_buf_confirm(pipe, buf);
> if (ret)
> goto out;
> @@ -439,7 +440,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
> buf->ops = &anon_pipe_buf_ops;
> buf->offset = 0;
> buf->len = copied;
> - buf->flags = 0;
> + buf->flags = PIPE_BUF_FLAG_MAYMERGE;
> if (is_packetized(filp)) {
> buf->ops = &packet_pipe_buf_ops;
> buf->flags = PIPE_BUF_FLAG_PACKET;
> diff --git a/fs/splice.c b/fs/splice.c
> index b3daa971f597..111977c80dfd 100644
> --- a/fs/splice.c
> +++ b/fs/splice.c
> @@ -1593,6 +1593,9 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
> */
> obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
>
> + /* We can't merge data into a buffer we don't own. */
> + obuf->flags &= ~PIPE_BUF_FLAG_MAYMERGE;
> +
> obuf->len = len;
> opipe->nrbufs++;
> ibuf->offset += obuf->len;
> @@ -1667,6 +1670,9 @@ static int link_pipe(struct pipe_inode_info *ipipe,
> */
> obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
>
> + /* We can't merge data into a buffer we don't own. */
> + obuf->flags &= ~PIPE_BUF_FLAG_MAYMERGE;
> +
> if (obuf->len > len)
> obuf->len = len;
>
> diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
> index 5a3bb3b7c9ad..8893711f9171 100644
> --- a/include/linux/pipe_fs_i.h
> +++ b/include/linux/pipe_fs_i.h
> @@ -8,6 +8,14 @@
> #define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */
> #define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */
> #define PIPE_BUF_FLAG_PACKET 0x08 /* read() as a packet */
> +/*
> + * Set this flag if the generic pipe read/write may coalesce data into an
> + * existing buffer. If this is not set, a new pipe page segment is always used
> + * for new data.
> + * When pipe data is copied by reference (as in the tee() syscall), this flag
> + * must be cleared on the copy.
> + */
> +#define PIPE_BUF_FLAG_MAYMERGE 0x10
>
> /**
> * struct pipe_buffer - a linux kernel pipe buffer
> --
> 2.19.0.605.g01d371f741-goog
>
Deja vu... https://marc.info/?l=linux-fsdevel&m=149003133809192
Thanks for fixing this; I think this is the right fix.
I verified it works for my reproducer too.
Did you check whether fuse_dev_splice_write() needs to clear
PIPE_BUF_FLAG_MAYMERGE?
- Eric
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] splice: don't merge into linked buffers
2018-10-15 21:00 ` [PATCH 1/2] splice: don't merge into linked buffers Eric Biggers
@ 2018-10-15 21:13 ` Jann Horn
0 siblings, 0 replies; 4+ messages in thread
From: Jann Horn @ 2018-10-15 21:13 UTC (permalink / raw)
To: ebiggers
Cc: Al Viro, Miklos Szeredi, Jens Axboe, Jens Axboe, kernel list,
linux-fsdevel, Kees Cook
On Mon, Oct 15, 2018 at 11:00 PM Eric Biggers <ebiggers@kernel.org> wrote:
> On Mon, Oct 15, 2018 at 05:04:18PM +0200, Jann Horn wrote:
> > Before this patch, it was possible for two pipes to affect each other after
> > data had been transferred between them with tee():
> >
> > ============
> > $ cat tee_test.c
> >
> > int main(void) {
> > int pipe_a[2];
> > if (pipe(pipe_a)) err(1, "pipe");
> > int pipe_b[2];
> > if (pipe(pipe_b)) err(1, "pipe");
> > if (write(pipe_a[1], "abcd", 4) != 4) err(1, "write");
> > if (tee(pipe_a[0], pipe_b[1], 2, 0) != 2) err(1, "tee");
> > if (write(pipe_b[1], "xx", 2) != 2) err(1, "write");
> >
> > char buf[5];
> > if (read(pipe_a[0], buf, 4) != 4) err(1, "read");
> > buf[4] = 0;
> > printf("got back: '%s'\n", buf);
> > }
> > $ gcc -o tee_test tee_test.c
> > $ ./tee_test
> > got back: 'abxx'
> > $
> > ============
> >
> > Fix it by explicitly marking buffers as mergeable and clearing that flag in
> > splice_pipe_to_pipe() and link_pipe().
> >
> > Cc: <stable@vger.kernel.org>
> > Fixes: 7c77f0b3f920 ("splice: implement pipe to pipe splicing")
> > Fixes: 70524490ee2e ("[PATCH] splice: add support for sys_tee()")
> > Signed-off-by: Jann Horn <jannh@google.com>
> > ---
> > Cleanup in the next patch, to simplify backporting.
> >
> > fs/pipe.c | 5 +++--
> > fs/splice.c | 6 ++++++
> > include/linux/pipe_fs_i.h | 8 ++++++++
> > 3 files changed, 17 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/pipe.c b/fs/pipe.c
> > index bdc5d3c0977d..4e2eee77f855 100644
> > --- a/fs/pipe.c
> > +++ b/fs/pipe.c
> > @@ -379,7 +379,8 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
> > struct pipe_buffer *buf = pipe->bufs + lastbuf;
> > int offset = buf->offset + buf->len;
> >
> > - if (buf->ops->can_merge && offset + chars <= PAGE_SIZE) {
> > + if (buf->ops->can_merge && offset + chars <= PAGE_SIZE &&
> > + (buf->flags & PIPE_BUF_FLAG_MAYMERGE)) {
> > ret = pipe_buf_confirm(pipe, buf);
> > if (ret)
> > goto out;
> > @@ -439,7 +440,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
> > buf->ops = &anon_pipe_buf_ops;
> > buf->offset = 0;
> > buf->len = copied;
> > - buf->flags = 0;
> > + buf->flags = PIPE_BUF_FLAG_MAYMERGE;
> > if (is_packetized(filp)) {
> > buf->ops = &packet_pipe_buf_ops;
> > buf->flags = PIPE_BUF_FLAG_PACKET;
> > diff --git a/fs/splice.c b/fs/splice.c
> > index b3daa971f597..111977c80dfd 100644
> > --- a/fs/splice.c
> > +++ b/fs/splice.c
> > @@ -1593,6 +1593,9 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
> > */
> > obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
> >
> > + /* We can't merge data into a buffer we don't own. */
> > + obuf->flags &= ~PIPE_BUF_FLAG_MAYMERGE;
> > +
> > obuf->len = len;
> > opipe->nrbufs++;
> > ibuf->offset += obuf->len;
> > @@ -1667,6 +1670,9 @@ static int link_pipe(struct pipe_inode_info *ipipe,
> > */
> > obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
> >
> > + /* We can't merge data into a buffer we don't own. */
> > + obuf->flags &= ~PIPE_BUF_FLAG_MAYMERGE;
> > +
> > if (obuf->len > len)
> > obuf->len = len;
> >
> > diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
> > index 5a3bb3b7c9ad..8893711f9171 100644
> > --- a/include/linux/pipe_fs_i.h
> > +++ b/include/linux/pipe_fs_i.h
> > @@ -8,6 +8,14 @@
> > #define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */
> > #define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */
> > #define PIPE_BUF_FLAG_PACKET 0x08 /* read() as a packet */
> > +/*
> > + * Set this flag if the generic pipe read/write may coalesce data into an
> > + * existing buffer. If this is not set, a new pipe page segment is always used
> > + * for new data.
> > + * When pipe data is copied by reference (as in the tee() syscall), this flag
> > + * must be cleared on the copy.
> > + */
> > +#define PIPE_BUF_FLAG_MAYMERGE 0x10
> >
> > /**
> > * struct pipe_buffer - a linux kernel pipe buffer
> > --
> > 2.19.0.605.g01d371f741-goog
> >
>
> Deja vu... https://marc.info/?l=linux-fsdevel&m=149003133809192
Oh, hah, even the reproducer looks almost the same. I hadn't seen that...
> Thanks for fixing this; I think this is the right fix.
> I verified it works for my reproducer too.
>
> Did you check whether fuse_dev_splice_write() needs to clear
> PIPE_BUF_FLAG_MAYMERGE?
No, I hadn't looked at that. But from what I can tell,
fuse_dev_splice_write() shouldn't write into the provided buffers,
only read from them.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-10-15 21:13 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2018-10-15 15:04 [PATCH 1/2] splice: don't merge into linked buffers Jann Horn
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2018-10-15 21:00 ` [PATCH 1/2] splice: don't merge into linked buffers Eric Biggers
2018-10-15 21:13 ` Jann Horn
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