The patch below does not apply to the 5.13-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 89c2b3b74918200e46699338d7bcc19b1ea12110 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence(a)gmail.com>
Date: Mon, 23 Aug 2021 11:18:45 +0100
Subject: [PATCH] io_uring: reexpand under-reexpanded iters
[ 74.211232] BUG: KASAN: stack-out-of-bounds in iov_iter_revert+0x809/0x900
[ 74.212778] Read of size 8 at addr ffff888025dc78b8 by task
syz-executor.0/828
[ 74.214756] CPU: 0 PID: 828 Comm: syz-executor.0 Not tainted
5.14.0-rc3-next-20210730 #1
[ 74.216525] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 74.219033] Call Trace:
[ 74.219683] dump_stack_lvl+0x8b/0xb3
[ 74.220706] print_address_description.constprop.0+0x1f/0x140
[ 74.224226] kasan_report.cold+0x7f/0x11b
[ 74.226085] iov_iter_revert+0x809/0x900
[ 74.227960] io_write+0x57d/0xe40
[ 74.232647] io_issue_sqe+0x4da/0x6a80
[ 74.242578] __io_queue_sqe+0x1ac/0xe60
[ 74.245358] io_submit_sqes+0x3f6e/0x76a0
[ 74.248207] __do_sys_io_uring_enter+0x90c/0x1a20
[ 74.257167] do_syscall_64+0x3b/0x90
[ 74.257984] entry_SYSCALL_64_after_hwframe+0x44/0xae
old_size = iov_iter_count();
...
iov_iter_revert(old_size - iov_iter_count());
If iov_iter_revert() is done base on the initial size as above, and the
iter is truncated and not reexpanded in the middle, it miscalculates
borders causing problems. This trace is due to no one reexpanding after
generic_write_checks().
Now iters store how many bytes has been truncated, so reexpand them to
the initial state right before reverting.
Cc: stable(a)vger.kernel.org
Reported-by: Palash Oswal <oswalpalash(a)gmail.com>
Reported-by: Sudip Mukherjee <sudipm.mukherjee(a)gmail.com>
Reported-and-tested-by: syzbot+9671693590ef5aad8953(a)syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence(a)gmail.com>
Signed-off-by: Al Viro <viro(a)zeniv.linux.org.uk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index d94fb5835a20..71639d39caf9 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3281,6 +3281,7 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags)
if (req->flags & REQ_F_NOWAIT)
goto done;
/* some cases will consume bytes even on error returns */
+ iov_iter_reexpand(iter, iter->count + iter->truncated);
iov_iter_revert(iter, io_size - iov_iter_count(iter));
ret = 0;
} else if (ret == -EIOCBQUEUED) {
@@ -3420,6 +3421,7 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags)
} else {
copy_iov:
/* some cases will consume bytes even on error returns */
+ iov_iter_reexpand(iter, iter->count + iter->truncated);
iov_iter_revert(iter, io_size - iov_iter_count(iter));
ret = io_setup_async_rw(req, iovec, inline_vecs, iter, false);
return ret ?: -EAGAIN;
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 2ae2eb9dde18979b40629dd413b9adbd6c894cdf Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence(a)gmail.com>
Date: Thu, 9 Sep 2021 13:56:27 +0100
Subject: [PATCH] io_uring: fail links of cancelled timeouts
When we cancel a timeout we should mark it with REQ_F_FAIL, so
linked requests are cancelled as well, but not queued for further
execution.
Cc: stable(a)vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence(a)gmail.com>
Link: https://lore.kernel.org/r/fff625b44eeced3a5cae79f60e6acf3fbdf8f990.16311921…
Signed-off-by: Jens Axboe <axboe(a)kernel.dk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index b21a423a4de8..ffd91844b2e5 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1482,6 +1482,8 @@ static void io_kill_timeout(struct io_kiocb *req, int status)
struct io_timeout_data *io = req->async_data;
if (hrtimer_try_to_cancel(&io->timer) != -1) {
+ if (status)
+ req_set_fail(req);
atomic_set(&req->ctx->cq_timeouts,
atomic_read(&req->ctx->cq_timeouts) + 1);
list_del_init(&req->timeout.list);
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 89c2b3b74918200e46699338d7bcc19b1ea12110 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence(a)gmail.com>
Date: Mon, 23 Aug 2021 11:18:45 +0100
Subject: [PATCH] io_uring: reexpand under-reexpanded iters
[ 74.211232] BUG: KASAN: stack-out-of-bounds in iov_iter_revert+0x809/0x900
[ 74.212778] Read of size 8 at addr ffff888025dc78b8 by task
syz-executor.0/828
[ 74.214756] CPU: 0 PID: 828 Comm: syz-executor.0 Not tainted
5.14.0-rc3-next-20210730 #1
[ 74.216525] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 74.219033] Call Trace:
[ 74.219683] dump_stack_lvl+0x8b/0xb3
[ 74.220706] print_address_description.constprop.0+0x1f/0x140
[ 74.224226] kasan_report.cold+0x7f/0x11b
[ 74.226085] iov_iter_revert+0x809/0x900
[ 74.227960] io_write+0x57d/0xe40
[ 74.232647] io_issue_sqe+0x4da/0x6a80
[ 74.242578] __io_queue_sqe+0x1ac/0xe60
[ 74.245358] io_submit_sqes+0x3f6e/0x76a0
[ 74.248207] __do_sys_io_uring_enter+0x90c/0x1a20
[ 74.257167] do_syscall_64+0x3b/0x90
[ 74.257984] entry_SYSCALL_64_after_hwframe+0x44/0xae
old_size = iov_iter_count();
...
iov_iter_revert(old_size - iov_iter_count());
If iov_iter_revert() is done base on the initial size as above, and the
iter is truncated and not reexpanded in the middle, it miscalculates
borders causing problems. This trace is due to no one reexpanding after
generic_write_checks().
Now iters store how many bytes has been truncated, so reexpand them to
the initial state right before reverting.
Cc: stable(a)vger.kernel.org
Reported-by: Palash Oswal <oswalpalash(a)gmail.com>
Reported-by: Sudip Mukherjee <sudipm.mukherjee(a)gmail.com>
Reported-and-tested-by: syzbot+9671693590ef5aad8953(a)syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence(a)gmail.com>
Signed-off-by: Al Viro <viro(a)zeniv.linux.org.uk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index d94fb5835a20..71639d39caf9 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3281,6 +3281,7 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags)
if (req->flags & REQ_F_NOWAIT)
goto done;
/* some cases will consume bytes even on error returns */
+ iov_iter_reexpand(iter, iter->count + iter->truncated);
iov_iter_revert(iter, io_size - iov_iter_count(iter));
ret = 0;
} else if (ret == -EIOCBQUEUED) {
@@ -3420,6 +3421,7 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags)
} else {
copy_iov:
/* some cases will consume bytes even on error returns */
+ iov_iter_reexpand(iter, iter->count + iter->truncated);
iov_iter_revert(iter, io_size - iov_iter_count(iter));
ret = io_setup_async_rw(req, iovec, inline_vecs, iter, false);
return ret ?: -EAGAIN;
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From dadebc350da2bef62593b1df007a6e0b90baf42a Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence(a)gmail.com>
Date: Mon, 23 Aug 2021 13:30:44 +0100
Subject: [PATCH] io_uring: fix io_try_cancel_userdata race for iowq
WARNING: CPU: 1 PID: 5870 at fs/io_uring.c:5975 io_try_cancel_userdata+0x30f/0x540 fs/io_uring.c:5975
CPU: 0 PID: 5870 Comm: iou-wrk-5860 Not tainted 5.14.0-rc6-next-20210820-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:io_try_cancel_userdata+0x30f/0x540 fs/io_uring.c:5975
Call Trace:
io_async_cancel fs/io_uring.c:6014 [inline]
io_issue_sqe+0x22d5/0x65a0 fs/io_uring.c:6407
io_wq_submit_work+0x1dc/0x300 fs/io_uring.c:6511
io_worker_handle_work+0xa45/0x1840 fs/io-wq.c:533
io_wqe_worker+0x2cc/0xbb0 fs/io-wq.c:582
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
io_try_cancel_userdata() can be called from io_async_cancel() executing
in the io-wq context, so the warning fires, which is there to alert
anyone accessing task->io_uring->io_wq in a racy way. However,
io_wq_put_and_exit() always first waits for all threads to complete,
so the only detail left is to zero tctx->io_wq after the context is
removed.
note: one little assumption is that when IO_WQ_WORK_CANCEL, the executor
won't touch ->io_wq, because io_wq_destroy() might cancel left pending
requests in such a way.
Cc: stable(a)vger.kernel.org
Reported-by: syzbot+b0c9d1588ae92866515f(a)syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence(a)gmail.com>
Link: https://lore.kernel.org/r/dfdd37a80cfa9ffd3e59538929c99cdd55d8699e.16297217…
Signed-off-by: Jens Axboe <axboe(a)kernel.dk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 827e60ae4909..6859438c4e09 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5863,7 +5863,7 @@ static int io_try_cancel_userdata(struct io_kiocb *req, u64 sqe_addr)
struct io_ring_ctx *ctx = req->ctx;
int ret;
- WARN_ON_ONCE(req->task != current);
+ WARN_ON_ONCE(!io_wq_current_is_worker() && req->task != current);
ret = io_async_cancel_one(req->task->io_uring, sqe_addr, ctx);
if (ret != -ENOENT)
@@ -6369,6 +6369,7 @@ static void io_wq_submit_work(struct io_wq_work *work)
if (timeout)
io_queue_linked_timeout(timeout);
+ /* either cancelled or io-wq is dying, so don't touch tctx->iowq */
if (work->flags & IO_WQ_WORK_CANCEL)
ret = -ECANCELED;
@@ -9184,8 +9185,8 @@ static void io_uring_clean_tctx(struct io_uring_task *tctx)
* Must be after io_uring_del_task_file() (removes nodes under
* uring_lock) to avoid race with io_uring_try_cancel_iowq().
*/
- tctx->io_wq = NULL;
io_wq_put_and_exit(wq);
+ tctx->io_wq = NULL;
}
}
The patch below does not apply to the 5.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From dadebc350da2bef62593b1df007a6e0b90baf42a Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence(a)gmail.com>
Date: Mon, 23 Aug 2021 13:30:44 +0100
Subject: [PATCH] io_uring: fix io_try_cancel_userdata race for iowq
WARNING: CPU: 1 PID: 5870 at fs/io_uring.c:5975 io_try_cancel_userdata+0x30f/0x540 fs/io_uring.c:5975
CPU: 0 PID: 5870 Comm: iou-wrk-5860 Not tainted 5.14.0-rc6-next-20210820-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:io_try_cancel_userdata+0x30f/0x540 fs/io_uring.c:5975
Call Trace:
io_async_cancel fs/io_uring.c:6014 [inline]
io_issue_sqe+0x22d5/0x65a0 fs/io_uring.c:6407
io_wq_submit_work+0x1dc/0x300 fs/io_uring.c:6511
io_worker_handle_work+0xa45/0x1840 fs/io-wq.c:533
io_wqe_worker+0x2cc/0xbb0 fs/io-wq.c:582
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
io_try_cancel_userdata() can be called from io_async_cancel() executing
in the io-wq context, so the warning fires, which is there to alert
anyone accessing task->io_uring->io_wq in a racy way. However,
io_wq_put_and_exit() always first waits for all threads to complete,
so the only detail left is to zero tctx->io_wq after the context is
removed.
note: one little assumption is that when IO_WQ_WORK_CANCEL, the executor
won't touch ->io_wq, because io_wq_destroy() might cancel left pending
requests in such a way.
Cc: stable(a)vger.kernel.org
Reported-by: syzbot+b0c9d1588ae92866515f(a)syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence(a)gmail.com>
Link: https://lore.kernel.org/r/dfdd37a80cfa9ffd3e59538929c99cdd55d8699e.16297217…
Signed-off-by: Jens Axboe <axboe(a)kernel.dk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 827e60ae4909..6859438c4e09 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5863,7 +5863,7 @@ static int io_try_cancel_userdata(struct io_kiocb *req, u64 sqe_addr)
struct io_ring_ctx *ctx = req->ctx;
int ret;
- WARN_ON_ONCE(req->task != current);
+ WARN_ON_ONCE(!io_wq_current_is_worker() && req->task != current);
ret = io_async_cancel_one(req->task->io_uring, sqe_addr, ctx);
if (ret != -ENOENT)
@@ -6369,6 +6369,7 @@ static void io_wq_submit_work(struct io_wq_work *work)
if (timeout)
io_queue_linked_timeout(timeout);
+ /* either cancelled or io-wq is dying, so don't touch tctx->iowq */
if (work->flags & IO_WQ_WORK_CANCEL)
ret = -ECANCELED;
@@ -9184,8 +9185,8 @@ static void io_uring_clean_tctx(struct io_uring_task *tctx)
* Must be after io_uring_del_task_file() (removes nodes under
* uring_lock) to avoid race with io_uring_try_cancel_iowq().
*/
- tctx->io_wq = NULL;
io_wq_put_and_exit(wq);
+ tctx->io_wq = NULL;
}
}
The patch below does not apply to the 5.13-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From dadebc350da2bef62593b1df007a6e0b90baf42a Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence(a)gmail.com>
Date: Mon, 23 Aug 2021 13:30:44 +0100
Subject: [PATCH] io_uring: fix io_try_cancel_userdata race for iowq
WARNING: CPU: 1 PID: 5870 at fs/io_uring.c:5975 io_try_cancel_userdata+0x30f/0x540 fs/io_uring.c:5975
CPU: 0 PID: 5870 Comm: iou-wrk-5860 Not tainted 5.14.0-rc6-next-20210820-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:io_try_cancel_userdata+0x30f/0x540 fs/io_uring.c:5975
Call Trace:
io_async_cancel fs/io_uring.c:6014 [inline]
io_issue_sqe+0x22d5/0x65a0 fs/io_uring.c:6407
io_wq_submit_work+0x1dc/0x300 fs/io_uring.c:6511
io_worker_handle_work+0xa45/0x1840 fs/io-wq.c:533
io_wqe_worker+0x2cc/0xbb0 fs/io-wq.c:582
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
io_try_cancel_userdata() can be called from io_async_cancel() executing
in the io-wq context, so the warning fires, which is there to alert
anyone accessing task->io_uring->io_wq in a racy way. However,
io_wq_put_and_exit() always first waits for all threads to complete,
so the only detail left is to zero tctx->io_wq after the context is
removed.
note: one little assumption is that when IO_WQ_WORK_CANCEL, the executor
won't touch ->io_wq, because io_wq_destroy() might cancel left pending
requests in such a way.
Cc: stable(a)vger.kernel.org
Reported-by: syzbot+b0c9d1588ae92866515f(a)syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence(a)gmail.com>
Link: https://lore.kernel.org/r/dfdd37a80cfa9ffd3e59538929c99cdd55d8699e.16297217…
Signed-off-by: Jens Axboe <axboe(a)kernel.dk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 827e60ae4909..6859438c4e09 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5863,7 +5863,7 @@ static int io_try_cancel_userdata(struct io_kiocb *req, u64 sqe_addr)
struct io_ring_ctx *ctx = req->ctx;
int ret;
- WARN_ON_ONCE(req->task != current);
+ WARN_ON_ONCE(!io_wq_current_is_worker() && req->task != current);
ret = io_async_cancel_one(req->task->io_uring, sqe_addr, ctx);
if (ret != -ENOENT)
@@ -6369,6 +6369,7 @@ static void io_wq_submit_work(struct io_wq_work *work)
if (timeout)
io_queue_linked_timeout(timeout);
+ /* either cancelled or io-wq is dying, so don't touch tctx->iowq */
if (work->flags & IO_WQ_WORK_CANCEL)
ret = -ECANCELED;
@@ -9184,8 +9185,8 @@ static void io_uring_clean_tctx(struct io_uring_task *tctx)
* Must be after io_uring_del_task_file() (removes nodes under
* uring_lock) to avoid race with io_uring_try_cancel_iowq().
*/
- tctx->io_wq = NULL;
io_wq_put_and_exit(wq);
+ tctx->io_wq = NULL;
}
}