commit 47da29763ec9a153b9b685bff9db659e4e09e494 upstream.
If userspace tries to change the stub, we need to kill it,
because otherwise it can escape the virtual machine. In a
few cases the stub checks weren't good, e.g. if userspace
just tries to
mmap(0x100000 - 0x1000, 0x3000, ...)
it could succeed to get a new private/anonymous mapping
replacing the stubs. Fix this by checking everywhere, and
checking for _overlap_, not just direct changes.
Cc: stable@vger.kernel.org
Fixes: 3963333fe676 ("uml: cover stubs with a VMA")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit f4172b084342fd3f9e38c10650ffe19eac30d8ce ]
Since struct device is refcounted, we shouldn't free the vu_dev
immediately when it's removed from the platform device, but only
when the references actually all go away. Move the freeing to
the release to accomplish that.
Fixes: 5d38f324993f ("um: drivers: Add virtio vhost-user driver")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit fc6b6a872dcd48c6f39c7975836d75113db67d37 ]
Internally, UBD treats each physical IO segment as a separate command to
be submitted in the execution pipe. If the pipe returns a transient
error after a few segments have already been written, UBD will tell the
block layer to requeue the request, but there is no way to reclaim the
segments already submitted. When a new attempt to dispatch the request
is done, those segments already submitted will get duplicated, causing
the WARN_ON below in the best case, and potentially data corruption.
In my system, running a UML instance with 2GB of RAM and a 50M UBD disk,
I can reproduce the WARN_ON by simply running mkfs.fvat against the
disk on a freshly booted system.
There are a few ways to around this, like reducing the pressure on
the pipe by reducing the queue depth, which almost eliminates the
occurrence of the problem, increasing the pipe buffer size on the host
system, or by limiting the request to one physical segment, which causes
the block layer to submit way more requests to resolve a single
operation.
Instead, this patch modifies the format of a UBD command, such that all
segments are sent through a single element in the communication pipe,
turning the command submission atomic from the point of view of the
block layer. The new format has a variable size, depending on the
number of elements, and looks like this:
+------------+-----------+-----------+------------
| cmd_header | segment 0 | segment 1 | segment ...
+------------+-----------+-----------+------------
With this format, we push a pointer to cmd_header in the submission
pipe.
This has the advantage of reducing the memory footprint of executing a
single request, since it allow us to merge some fields in the header.
It is possible to reduce even further each segment memory footprint, by
merging bitmap_words and cow_offset, for instance, but this is not the
focus of this patch and is left as future work. One issue with the
patch is that for a big number of segments, we now perform one big
memory allocation instead of multiple small ones, but I wasn't able to
trigger any real issues or -ENOMEM because of this change, that wouldn't
be reproduced otherwise.
This was tested using fio with the verify-crc32 option, and by running
an ext4 filesystem over this UBD device.
The original WARN_ON was:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at lib/refcount.c:28 refcount_warn_saturate+0x13f/0x141
refcount_t: underflow; use-after-free.
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 5.5.0-rc6-00002-g2a5bb2cf75c8 #346
Stack:
6084eed0 6063dc77 00000009 6084ef60
00000000 604b8d9f 6084eee0 6063dcbc
6084ef40 6006ab8d e013d780 1c00000000
Call Trace:
[<600a0c1c>] ? printk+0x0/0x94
[<6004a888>] show_stack+0x13b/0x155
[<6063dc77>] ? dump_stack_print_info+0xdf/0xe8
[<604b8d9f>] ? refcount_warn_saturate+0x13f/0x141
[<6063dcbc>] dump_stack+0x2a/0x2c
[<6006ab8d>] __warn+0x107/0x134
[<6008da6c>] ? wake_up_process+0x17/0x19
[<60487628>] ? blk_queue_max_discard_sectors+0x0/0xd
[<6006b05f>] warn_slowpath_fmt+0xd1/0xdf
[<6006af8e>] ? warn_slowpath_fmt+0x0/0xdf
[<600acc14>] ? raw_read_seqcount_begin.constprop.0+0x0/0x15
[<600619ae>] ? os_nsecs+0x1d/0x2b
[<604b8d9f>] refcount_warn_saturate+0x13f/0x141
[<6048bc8f>] refcount_sub_and_test.constprop.0+0x2f/0x37
[<6048c8de>] blk_mq_free_request+0xf1/0x10d
[<6048ca06>] __blk_mq_end_request+0x10c/0x114
[<6005ac0f>] ubd_intr+0xb5/0x169
[<600a1a37>] __handle_irq_event_percpu+0x6b/0x17e
[<600a1b70>] handle_irq_event_percpu+0x26/0x69
[<600a1bd9>] handle_irq_event+0x26/0x34
[<600a1bb3>] ? handle_irq_event+0x0/0x34
[<600a5186>] ? unmask_irq+0x0/0x37
[<600a57e6>] handle_edge_irq+0xbc/0xd6
[<600a131a>] generic_handle_irq+0x21/0x29
[<60048f6e>] do_IRQ+0x39/0x54
[...]
---[ end trace c6e7444e55386c0f ]---
Cc: Christopher Obbard <chris.obbard@collabora.com>
Reported-by: Martyn Welch <martyn@collabora.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Tested-by: Christopher Obbard <chris.obbard@collabora.com>
Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 97be7ceaf7fea68104824b6aa874cff235333ac1 upstream.
asprintf is not compatible with the existing uml memory allocation
mechanism. Its use on the "user" side of UML results in a corrupt slab
state.
Fixes: 0d4e5ac7e780 ("um: remove uses of variable length arrays")
Cc: stable@vger.kernel.org
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 9431f7c199ab0d02da1482d62255e0b4621cb1b5 ]
xterm serial channel was leaking a fd used in setting up the
port helper
This bug is prehistoric - it predates switching to git. The "fixes"
header here is really just to mark all the versions we would like this to
apply to which is "Anything from the Cretaceous period onwards".
No dinosaurs were harmed in fixing this bug.
Fixes: b40997b872cd ("um: drivers/xterm.c: fix a file descriptor leak")
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 9b1c0c0e25dcccafd30e7d4c150c249cc65550eb ]
Fix a logical error in tty reading. We get 0 and errno == EAGAIN
on the first attempt to read from a closed file descriptor.
Compared to that a true EAGAIN is EAGAIN and -1.
If we check errno for EAGAIN first, before checking the return
value we miss the fact that the descriptor is closed.
This bug is as old as the driver. It was not showing up with
the original POLL based IRQ controller, because it was
producing multiple events. Switching to EPOLL unmasked it.
Fixes: ff6a17989c08 ("Epoll based IRQ controller")
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e3a01cbee9c5f2c6fc813dd6af007716e60257e7 ]
Ensure that file closes, connection closes, etc are propagated
as interrupts in the interrupt controller.
Fixes: ff6a17989c08 ("Epoll based IRQ controller")
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit f2d05059e15af3f70502074f4e3a504530af504a ]
Lockdep complains at boot:
=============================
[ BUG: Invalid wait context ]
5.7.0-05093-g46d91ecd597b #98 Not tainted
-----------------------------
swapper/1 is trying to lock:
0000000060931b98 (&desc[i].request_mutex){+.+.}-{3:3}, at: __setup_irq+0x11d/0x623
other info that might help us debug this:
context-{4:4}
1 lock held by swapper/1:
#0: 000000006074fed8 (sigio_spinlock){+.+.}-{2:2}, at: sigio_lock+0x1a/0x1c
stack backtrace:
CPU: 0 PID: 1 Comm: swapper Not tainted 5.7.0-05093-g46d91ecd597b #98
Stack:
7fa4fab0 6028dfd1 0000002a 6008bea5
7fa50700 7fa50040 7fa4fac0 6028e016
7fa4fb50 6007f6da 60959c18 00000000
Call Trace:
[<60023a0e>] show_stack+0x13b/0x155
[<6028e016>] dump_stack+0x2a/0x2c
[<6007f6da>] __lock_acquire+0x515/0x15f2
[<6007eb50>] lock_acquire+0x245/0x273
[<6050d9f1>] __mutex_lock+0xbd/0x325
[<6050dc76>] mutex_lock_nested+0x1d/0x1f
[<6008e27e>] __setup_irq+0x11d/0x623
[<6008e8ed>] request_threaded_irq+0x169/0x1a6
[<60021eb0>] um_request_irq+0x1ee/0x24b
[<600234ee>] write_sigio_irq+0x3b/0x76
[<600383ca>] sigio_broken+0x146/0x2e4
[<60020bd8>] do_one_initcall+0xde/0x281
Because we hold sigio_spinlock and then get into requesting
an interrupt with a mutex.
Change the spinlock to a mutex to avoid that.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 35f3401317a3b26aa01fde8facfd320f2628fdcc ]
When building UML with glibc 2.17 installed, compilation
of arch/um/os-Linux/file.c fails due to failure to find
FALLOC_FL_PUNCH_HOLE and FALLOC_FL_KEEP_SIZE definitions.
It appears that /usr/include/bits/fcntl-linux.h (indirectly
included by /usr/include/fcntl.h) does not include falloc.h
with an older glibc, whereas a more up-to-date version
does.
Adding the direct include to file.c resolves the issue
and does not cause problems for more recent glibc.
Fixes: 50109b5a03b4 ("um: Add support for DISCARD in the UBD Driver")
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6e682d53fc1ef73a169e2a5300326cb23abb32ee ]
On the hypervisor side, when completing commands and the pipe is full,
we retry writing only the entries that failed, by offsetting
io_req_buffer, but we don't reduce the number of bytes written, which
can cause a buffer overrun of io_req_buffer, and write garbage to the
pipe.
Cc: Martyn Welch <martyn.welch@collabora.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Johannes Berg