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[ Upstream commit da36a2a76b01b210ffaa55cdc2c99bc8783697c5 ]
In device_add(), dev_set_name() is called to allocate name, if it returns
error, the name need be freed. As comment of device_register() says, it
should use put_device() to give up the reference in the error path. So fix
this by calling put_device(), then the name can be freed in kobject_cleanup().
Fixes: f65c9bb3fb72 ("xen/pcpu: Xen physical cpus online/offline sys interface")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20221110152441.401630-1-yangyingliang@huawei.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 0991028cd49567d7016d1b224fe0117c35059f86 upstream.
Prior to this commit, if a grant mapping operation failed partially,
some of the entries in the map_ops array would be invalid, whereas all
of the entries in the kmap_ops array would be valid. This in turn would
cause the following logic in gntdev_map_grant_pages to become invalid:
for (i = 0; i < map->count; i++) {
if (map->map_ops[i].status == GNTST_okay) {
map->unmap_ops[i].handle = map->map_ops[i].handle;
if (!use_ptemod)
alloced++;
}
if (use_ptemod) {
if (map->kmap_ops[i].status == GNTST_okay) {
if (map->map_ops[i].status == GNTST_okay)
alloced++;
map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
}
}
}
...
atomic_add(alloced, &map->live_grants);
Assume that use_ptemod is true (i.e., the domain mapping the granted
pages is a paravirtualized domain). In the code excerpt above, note that
the "alloced" variable is only incremented when both kmap_ops[i].status
and map_ops[i].status are set to GNTST_okay (i.e., both mapping
operations are successful). However, as also noted above, there are
cases where a grant mapping operation fails partially, breaking the
assumption of the code excerpt above.
The aforementioned causes map->live_grants to be incorrectly set. In
some cases, all of the map_ops mappings fail, but all of the kmap_ops
mappings succeed, meaning that live_grants may remain zero. This in turn
makes it impossible to unmap the successfully grant-mapped pages pointed
to by kmap_ops, because unmap_grant_pages has the following snippet of
code at its beginning:
if (atomic_read(&map->live_grants) == 0)
return; /* Nothing to do */
In other cases where only some of the map_ops mappings fail but all
kmap_ops mappings succeed, live_grants is made positive, but when the
user requests unmapping the grant-mapped pages, __unmap_grant_pages_done
will then make map->live_grants negative, because the latter function
does not check if all of the pages that were requested to be unmapped
were actually unmapped, and the same function unconditionally subtracts
"data->count" (i.e., a value that can be greater than map->live_grants)
from map->live_grants. The side effects of a negative live_grants value
have not been studied.
The net effect of all of this is that grant references are leaked in one
of the above conditions. In Qubes OS v4.1 (which uses Xen's grant
mechanism extensively for X11 GUI isolation), this issue manifests
itself with warning messages like the following to be printed out by the
Linux kernel in the VM that had granted pages (that contain X11 GUI
window data) to dom0: "g.e. 0x1234 still pending", especially after the
user rapidly resizes GUI VM windows (causing some grant-mapping
operations to partially or completely fail, due to the fact that the VM
unshares some of the pages as part of the window resizing, making the
pages impossible to grant-map from dom0).
The fix for this issue involves counting all successful map_ops and
kmap_ops mappings separately, and then adding the sum to live_grants.
During unmapping, only the number of successfully unmapped grants is
subtracted from live_grants. The code is also modified to check for
negative live_grants values after the subtraction and warn the user.
Link: https://github.com/QubesOS/qubes-issues/issues/7631
Fixes: dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()")
Cc: stable@vger.kernel.org
Signed-off-by: M. Vefa Bicakci <m.v.b@runbox.com>
Acked-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20221002222006.2077-2-m.v.b@runbox.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f28347cc66395e96712f5c2db0a302ee75bafce6 upstream.
While working on XSA-361 and its follow-ups, I failed to spot another
place where the kernel mapping part of an operation was not treated the
same as the user space part. Detect and propagate errors and add a 2nd
pr_debug().
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/c2513395-74dc-aea3-9192-fd265aa44e35@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Co-authored-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 32ad11127b95236dfc52375f3707853194a7f4b4 upstream.
This code tries to store -EFAULT in an unsigned int. The
xenbus_file_read() function returns type ssize_t so the negative value
is returned as a positive value to the user.
This change forces another change to the min() macro. Originally, the
min() macro used "unsigned" type which checkpatch complains about. Also
unsigned type would break if "len" were not capped at MAX_RW_COUNT. Use
size_t for the min(). (No effect on runtime for the min_t() change).
Fixes: 2fb3683e7b16 ("xen: Add xenbus device driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Link: https://lore.kernel.org/r/YutxJUaUYRG/VLVc@kili
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 166d3863231667c4f64dee72b77d1102cdfad11f upstream.
The error paths of gntdev_mmap() can call unmap_grant_pages() even
though not all of the pages have been successfully mapped. This will
trigger the WARN_ON()s in __unmap_grant_pages_done(). The number of
warnings can be very large; I have observed thousands of lines of
warnings in the systemd journal.
Avoid this problem by only warning on unmapping failure if the handle
being unmapped is not INVALID_GRANT_HANDLE. The handle field of any
page that was not successfully mapped will be INVALID_GRANT_HANDLE, so
this catches all cases where unmapping can legitimately fail.
Fixes: dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()")
Cc: stable@vger.kernel.org
Suggested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220710230522.1563-1-demi@invisiblethingslab.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit dbe97cff7dd9f0f75c524afdd55ad46be3d15295 upstream.
unmap_grant_pages() currently waits for the pages to no longer be used.
In https://github.com/QubesOS/qubes-issues/issues/7481, this lead to a
deadlock against i915: i915 was waiting for gntdev's MMU notifier to
finish, while gntdev was waiting for i915 to free its pages. I also
believe this is responsible for various deadlocks I have experienced in
the past.
Avoid these problems by making unmap_grant_pages async. This requires
making it return void, as any errors will not be available when the
function returns. Fortunately, the only use of the return value is a
WARN_ON(), which can be replaced by a WARN_ON when the error is
detected. Additionally, a failed call will not prevent further calls
from being made, but this is harmless.
Because unmap_grant_pages is now async, the grant handle will be sent to
INVALID_GRANT_HANDLE too late to prevent multiple unmaps of the same
handle. Instead, a separate bool array is allocated for this purpose.
This wastes memory, but stuffing this information in padding bytes is
too fragile. Furthermore, it is necessary to grab a reference to the
map before making the asynchronous call, and release the reference when
the call returns.
It is also necessary to guard against reentrancy in gntdev_map_put(),
and to handle the case where userspace tries to map a mapping whose
contents have not all been freed yet.
Fixes: 745282256c75 ("xen/gntdev: safely unmap grants in case they are still in use")
Cc: stable@vger.kernel.org
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220622022726.2538-1-demi@invisiblethingslab.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit dbac14a5a05ff8e1ce7c0da0e1f520ce39ec62ea upstream.
EXPORT_SYMBOL and __init is a bad combination because the .init.text
section is freed up after the initialization. Hence, modules cannot
use symbols annotated __init. The access to a freed symbol may end up
with kernel panic.
modpost used to detect it, but it has been broken for a decade.
Recently, I fixed modpost so it started to warn it again, then this
showed up in linux-next builds.
There are two ways to fix it:
- Remove __init
- Remove EXPORT_SYMBOL
I chose the latter for this case because none of the in-tree call-sites
(arch/arm/xen/enlighten.c, arch/x86/xen/grant-table.c) is compiled as
modular.
Fixes: 243848fc018c ("xen/grant-table: Move xlated_setup_gnttab_pages to common place")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20220606045920.4161881-1-masahiroy@kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 42baefac638f06314298087394b982ead9ec444b upstream.
gnttab_end_foreign_access() is used to free a grant reference and
optionally to free the associated page. In case the grant is still in
use by the other side processing is being deferred. This leads to a
problem in case no page to be freed is specified by the caller: the
caller doesn't know that the page is still mapped by the other side
and thus should not be used for other purposes.
The correct way to handle this situation is to take an additional
reference to the granted page in case handling is being deferred and
to drop that reference when the grant reference could be freed
finally.
This requires that there are no users of gnttab_end_foreign_access()
left directly repurposing the granted page after the call, as this
might result in clobbered data or information leaks via the not yet
freed grant reference.
This is part of CVE-2022-23041 / XSA-396.
Reported-by: Simon Gaiser <simon@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 1dbd11ca75fe664d3e54607547771d021f531f59 upstream.
Remove gnttab_query_foreign_access(), as it is unused and unsafe to
use.
All previous use cases assumed a grant would not be in use after
gnttab_query_foreign_access() returned 0. This information is useless
in best case, as it only refers to a situation in the past, which could
have changed already.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit d3b6372c5881cb54925212abb62c521df8ba4809 upstream.
Using gnttab_query_foreign_access() is unsafe, as it is racy by design.
The use case in the gntalloc driver is not needed at all. While at it
replace the call of gnttab_end_foreign_access_ref() with a call of
gnttab_end_foreign_access(), which is what is really wanted there. In
case the grant wasn't used due to an allocation failure, just free the
grant via gnttab_free_grant_reference().
This is CVE-2022-23039 / part of XSA-396.
Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 6b1775f26a2da2b05a6dc8ec2b5d14e9a4701a1a upstream.
Add a new grant table function gnttab_try_end_foreign_access(), which
will remove and free a grant if it is not in use.
Its main use case is to either free a grant if it is no longer in use,
or to take some other action if it is still in use. This other action
can be an error exit, or (e.g. in the case of blkfront persistent grant
feature) some special handling.
This is CVE-2022-23036, CVE-2022-23038 / part of XSA-396.
Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 3777ea7bac3113005b7180e6b9dadf16d19a5827 upstream.
Letting xenbus_grant_ring() tear down grants in the error case is
problematic, as the other side could already have used these grants.
Calling gnttab_end_foreign_access_ref() without checking success is
resulting in an unclear situation for any caller of xenbus_grant_ring()
as in the error case the memory pages of the ring page might be
partially mapped. Freeing them would risk unwanted foreign access to
them, while not freeing them would leak memory.
In order to remove the need to undo any gnttab_grant_foreign_access()
calls, use gnttab_alloc_grant_references() to make sure no further
error can occur in the loop granting access to the ring pages.
It should be noted that this way of handling removes leaking of
grant entries in the error case, too.
This is CVE-2022-23040 / part of XSA-396.
Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 36e8f60f0867d3b70d398d653c17108459a04efe upstream.
If the xenstore page hasn't been allocated properly, reading the value
of the related hvm_param (HVM_PARAM_STORE_PFN) won't actually return
error. Instead, it will succeed and return zero. Instead of attempting
to xen_remap a bad guest physical address, detect this condition and
return early.
Note that although a guest physical address of zero for
HVM_PARAM_STORE_PFN is theoretically possible, it is not a good choice
and zero has never been validly used in that capacity.
Also recognize all bits set as an invalid value.
For 32-bit Linux, any pfn above ULONG_MAX would get truncated. Pfns
above ULONG_MAX should never be passed by the Xen tools to HVM guests
anyway, so check for this condition and return early.
Cc: stable@vger.kernel.org
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Link: https://lore.kernel.org/r/20211123210748.1910236-1-sstabellini@kernel.org
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 08f6c2b09ebd4b326dbe96d13f94fee8f9814c78 upstream.
In case of errors in xenbus_init (e.g. missing xen_store_gfn parameter),
we goto out_error but we forget to reset xen_store_domain_type to
XS_UNKNOWN. As a consequence xenbus_probe_initcall and other initcalls
will still try to initialize xenstore resulting into a crash at boot.
[ 2.479830] Call trace:
[ 2.482314] xb_init_comms+0x18/0x150
[ 2.486354] xs_init+0x34/0x138
[ 2.489786] xenbus_probe+0x4c/0x70
[ 2.498432] xenbus_probe_initcall+0x2c/0x7c
[ 2.503944] do_one_initcall+0x54/0x1b8
[ 2.507358] kernel_init_freeable+0x1ac/0x210
[ 2.511617] kernel_init+0x28/0x130
[ 2.516112] ret_from_fork+0x10/0x20
Cc: <Stable@vger.kernel.org>
Cc: jbeulich@suse.com
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Link: https://lore.kernel.org/r/20211115222719.2558207-1-sstabellini@kernel.org
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 4745ea2628bb43a7ec34b71763b5a56407b33990 ]
Return NULL instead of passing to ERR_PTR while err is zero,
this fix smatch warnings:
drivers/xen/xen-pciback/conf_space_capability.c:163
pm_ctrl_init() warn: passing zero to 'ERR_PTR'
Fixes: a92336a1176b ("xen/pciback: Drop two backends, squash and cleanup some code.")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20211008074417.8260-1-yuehaibing@huawei.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 88ca2521bd5b4e8b83743c01a2d4cb09325b51e9 ]
There is a TOCTOU issue in set_evtchn_to_irq. Rows in the evtchn_to_irq
mapping are lazily allocated in this function. The check whether the row
is already present and the row initialization is not synchronized. Two
threads can at the same time allocate a new row for evtchn_to_irq and
add the irq mapping to the their newly allocated row. One thread will
overwrite what the other has set for evtchn_to_irq[row] and therefore
the irq mapping is lost. This will trigger a BUG_ON later in
bind_evtchn_to_cpu:
INFO: pci 0000:1a:15.4: [1d0f:8061] type 00 class 0x010802
INFO: nvme 0000:1a:12.1: enabling device (0000 -> 0002)
INFO: nvme nvme77: 1/0/0 default/read/poll queues
CRIT: kernel BUG at drivers/xen/events/events_base.c:427!
WARN: invalid opcode: 0000 [#1] SMP NOPTI
WARN: Workqueue: nvme-reset-wq nvme_reset_work [nvme]
WARN: RIP: e030:bind_evtchn_to_cpu+0xc2/0xd0
WARN: Call Trace:
WARN: set_affinity_irq+0x121/0x150
WARN: irq_do_set_affinity+0x37/0xe0
WARN: irq_setup_affinity+0xf6/0x170
WARN: irq_startup+0x64/0xe0
WARN: __setup_irq+0x69e/0x740
WARN: ? request_threaded_irq+0xad/0x160
WARN: request_threaded_irq+0xf5/0x160
WARN: ? nvme_timeout+0x2f0/0x2f0 [nvme]
WARN: pci_request_irq+0xa9/0xf0
WARN: ? pci_alloc_irq_vectors_affinity+0xbb/0x130
WARN: queue_request_irq+0x4c/0x70 [nvme]
WARN: nvme_reset_work+0x82d/0x1550 [nvme]
WARN: ? check_preempt_wakeup+0x14f/0x230
WARN: ? check_preempt_curr+0x29/0x80
WARN: ? nvme_irq_check+0x30/0x30 [nvme]
WARN: process_one_work+0x18e/0x3c0
WARN: worker_thread+0x30/0x3a0
WARN: ? process_one_work+0x3c0/0x3c0
WARN: kthread+0x113/0x130
WARN: ? kthread_park+0x90/0x90
WARN: ret_from_fork+0x3a/0x50
This patch sets evtchn_to_irq rows via a cmpxchg operation so that they
will be set only once. The row is now cleared before writing it to
evtchn_to_irq in order to not create a race once the row is visible for
other threads.
While at it, do not require the page to be zeroed, because it will be
overwritten with -1's in clear_evtchn_to_irq_row anyway.
Signed-off-by: Maximilian Heyne <mheyne@amazon.de>
Fixes: d0b075ffeede ("xen/events: Refactor evtchn_to_irq array to be dynamically allocated")
Link: https://lore.kernel.org/r/20210812130930.127134-1-mheyne@amazon.de
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 3de218ff39b9e3f0d453fe3154f12a174de44b25 upstream.
In order to avoid a race condition for user events when changing
cpu affinity reset the active flag only when EOI-ing the event.
This is working fine as all user events are lateeoi events. Note that
lateeoi_ack_mask_dynirq() is not modified as there is no explicit call
to xen_irq_lateeoi() expected later.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Fixes: b6622798bc50b62 ("xen/events: avoid handling the same event on two cpus at the same time")
Tested-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrvsky@oracle.com>
Link: https://lore.kernel.org/r/20210623130913.9405-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The commit referenced below was incomplete: It merely affected what
would get written to the vdev-<N> xenstore node. The guest would still
find the function at the original function number as long as
__xen_pcibk_get_pci_dev() wouldn't be in sync. The same goes for AER wrt
__xen_pcibk_get_pcifront_dev().
Undo overriding the function to zero and instead make sure that VFs at
function zero remain alone in their slot. This has the added benefit of
improving overall capacity, considering that there's only a total of 32
slots available right now (PCI segment and bus can both only ever be
zero at present).
This is upstream commit 4ba50e7c423c29639878c00573288869aa627068.
Fixes: 8a5248fe10b1 ("xen PV passthru: assign SR-IOV virtual functions to
separate virtual slots")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/8def783b-404c-3452-196d-3f3fd4d72c9e@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c81d3d24602540f65256f98831d0a25599ea6b87 upstream.
When multiple PCI devices get assigned to a guest right at boot, libxl
incrementally populates the backend tree. The writes for the first of
the devices trigger the backend watch. In turn xen_pcibk_setup_backend()
will set the XenBus state to Initialised, at which point no further
reconfigures would happen unless a device got hotplugged. Arrange for
reconfigure to also get triggered from the backend watch handler.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/2337cbd6-94b9-4187-9862-c03ea12e0c61@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The backport of upstream patch 25da4618af240fbec61 ("xen/events: don't
unmask an event channel when an eoi is pending") introduced a
regression for stable kernels 5.10 and older: setting IRQ affinity for
IRQs related to interdomain events would no longer work, as moving the
IRQ to its new cpu was not included in the irq_ack callback for those
events.
Fix that by adding the needed call.
Note that kernels 5.11 and later don't need the explicit moving of the
IRQ to the target cpu in the irq_ack callback, due to a rework of the
affinity setting in kernel 5.11.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d120198bd5ff1d41808b6914e1eb89aff937415c upstream.
Unmask operation must be called with interrupt disabled,
on preempt_rt spin_lock_irqsave/spin_unlock_irqrestore
don't disable/enable interrupts, so use raw_* implementation
and change lock variable in struct irq_info from spinlock_t
to raw_spinlock_t
Cc: stable@vger.kernel.org
Fixes: 25da4618af24 ("xen/events: don't unmask an event channel when an eoi is pending")
Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20210406105105.10141-1-luca.fancellu@arm.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b6622798bc50b625a1e62f82c7190df40c1f5b21 upstream.
When changing the cpu affinity of an event it can happen today that
(with some unlucky timing) the same event will be handled on the old
and the new cpu at the same time.
Avoid that by adding an "event active" flag to the per-event data and
call the handler only if this flag isn't set.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Link: https://lore.kernel.org/r/20210306161833.4552-4-jgross@suse.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 25da4618af240fbec6112401498301a6f2bc9702 upstream.
An event channel should be kept masked when an eoi is pending for it.
When being migrated to another cpu it might be unmasked, though.
In order to avoid this keep three different flags for each event channel
to be able to distinguish "normal" masking/unmasking from eoi related
masking/unmasking and temporary masking. The event channel should only
be able to generate an interrupt if all flags are cleared.
Cc: stable@vger.kernel.org
Fixes: 54c9de89895e ("xen/events: add a new "late EOI" evtchn framework")
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Tested-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Link: https://lore.kernel.org/r/20210306161833.4552-3-jgross@suse.com
[boris -- corrected Fixed tag format]
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9e77d96b8e2724ed00380189f7b0ded61113b39f upstream.
When creating a new event channel with 2-level events the affinity
needs to be reset initially in order to avoid using an old affinity
from earlier usage of the event channel port. So when tearing an event
channel down reset all affinity bits.
The same applies to the affinity when onlining a vcpu: all old
affinity settings for this vcpu must be reset. As percpu events get
initialized before the percpu event channel hook is called,
resetting of the affinities happens after offlining a vcpu (this is
working, as initial percpu memory is zeroed out).
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Link: https://lore.kernel.org/r/20210306161833.4552-2-jgross@suse.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7c77474b2d22176d2bfb592ec74e0f2cb71352c9 upstream.
In particular -ENOMEM may come back here, from set_foreign_p2m_mapping().
Don't make problems worse, the more that handling elsewhere (together
with map's status fields now indicating whether a mapping wasn't even
attempted, and hence has to be considered failed) doesn't require this
odd way of dealing with errors.
This is part of XSA-362.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ebee0eab08594b2bd5db716288a4f1ae5936e9bc upstream.
Failure of the kernel part of the mapping operation should also be
indicated as an error to the caller, or else it may assume the
respective kernel VA is okay to access.
Furthermore gnttab_map_refs() failing still requires recording
successfully mapped handles, so they can be unmapped subsequently. This
in turn requires there to be a way to tell full hypercall failure from
partial success - preset map_op status fields such that they won't
"happen" to look as if the operation succeeded.
Also again use GNTST_okay instead of implying its value (zero).
This is part of XSA-361.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit dbe5283605b3bc12ca45def09cc721a0a5c853a2 upstream.
We may not skip setting the field in the unmap structure when
GNTMAP_device_map is in use - such an unmap would fail to release the
respective resources (a page ref in the hypervisor). Otoh the field
doesn't need setting at all when GNTMAP_device_map is not in use.
To record the value for unmapping, we also better don't use our local
p2m: In particular after a subsequent change it may not have got updated
for all the batch elements. Instead it can simply be taken from the
respective map's results.
We can additionally avoid playing this game altogether for the kernel
part of the mappings in (x86) PV mode.
This is part of XSA-361.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9996bd494794a2fe393e97e7a982388c6249aa76 upstream.
'xenbus_backend' watches 'state' of devices, which is writable by
guests. Hence, if guests intensively updates it, dom0 will have lots of
pending events that exhausting memory of dom0. In other words, guests
can trigger dom0 memory pressure. This is known as XSA-349. However,
the watch callback of it, 'frontend_changed()', reads only 'state', so
doesn't need to have the pending events.
To avoid the problem, this commit disallows pending watch messages for
'xenbus_backend' using the 'will_handle()' watch callback.
This is part of XSA-349
Cc: stable@vger.kernel.org
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reported-by: Michael Kurth <mku@amazon.de>
Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3dc86ca6b4c8cfcba9da7996189d1b5a358a94fc upstream.
This commit adds a counter of pending messages for each watch in the
struct. It is used to skip unnecessary pending messages lookup in
'unregister_xenbus_watch()'. It could also be used in 'will_handle'
callback.
This is part of XSA-349
Cc: stable@vger.kernel.org
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reported-by: Michael Kurth <mku@amazon.de>
Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit be987200fbaceaef340872841d4f7af2c5ee8dc3 upstream.
This commit adds support of the 'will_handle' watch callback for
'xen_bus_type' users.
This is part of XSA-349
Cc: stable@vger.kernel.org
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reported-by: Michael Kurth <mku@amazon.de>
Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2e85d32b1c865bec703ce0c962221a5e955c52c2 upstream.
Some code does not directly make 'xenbus_watch' object and call
'register_xenbus_watch()' but use 'xenbus_watch_path()' instead. This
commit adds support of 'will_handle' callback in the
'xenbus_watch_path()' and it's wrapper, 'xenbus_watch_pathfmt()'.
This is part of XSA-349
Cc: stable@vger.kernel.org
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reported-by: Michael Kurth <mku@amazon.de>
Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit fed1755b118147721f2c87b37b9d66e62c39b668 upstream.
If handling logics of watch events are slower than the events enqueue
logic and the events can be created from the guests, the guests could
trigger memory pressure by intensively inducing the events, because it
will create a huge number of pending events that exhausting the memory.
Fortunately, some watch events could be ignored, depending on its
handler callback. For example, if the callback has interest in only one
single path, the watch wouldn't want multiple pending events. Or, some
watches could ignore events to same path.
To let such watches to volutarily help avoiding the memory pressure
situation, this commit introduces new watch callback, 'will_handle'. If
it is not NULL, it will be called for each new event just before
enqueuing it. Then, if the callback returns false, the event will be
discarded. No watch is using the callback for now, though.
This is part of XSA-349
Cc: stable@vger.kernel.org
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reported-by: Michael Kurth <mku@amazon.de>
Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5f7f77400ab5b357b5fdb7122c3442239672186c upstream.
In order to avoid high dom0 load due to rogue guests sending events at
high frequency, block those events in case there was no action needed
in dom0 to handle the events.
This is done by adding a per-event counter, which set to zero in case
an EOI without the XEN_EOI_FLAG_SPURIOUS is received from a backend
driver, and incremented when this flag has been set. In case the
counter is 2 or higher delay the EOI by 1 << (cnt - 2) jiffies, but
not more than 1 second.
In order not to waste memory shorten the per-event refcnt to two bytes
(it should normally never exceed a value of 2). Add an overflow check
to evtchn_get() to make sure the 2 bytes really won't overflow.
This is part of XSA-332.
Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e99502f76271d6bc4e374fe368c50c67a1fd3070 upstream.
In case rogue guests are sending events at high frequency it might
happen that xen_evtchn_do_upcall() won't stop processing events in
dom0. As this is done in irq handling a crash might be the result.
In order to avoid that, delay further inter-domain events after some
time in xen_evtchn_do_upcall() by forcing eoi processing into a
worker on the same cpu, thus inhibiting new events coming in.
The time after which eoi processing is to be delayed is configurable
via a new module parameter "event_loop_timeout" which specifies the
maximum event loop time in jiffies (default: 2, the value was chosen
after some tests showing that a value of 2 was the lowest with an
only slight drop of dom0 network throughput while multiple guests
performed an event storm).
How long eoi processing will be delayed can be specified via another
parameter "event_eoi_delay" (again in jiffies, default 10, again the
value was chosen after testing with different delay values).
This is part of XSA-332.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7beb290caa2adb0a399e735a1e175db9aae0523a upstream.
Today only fifo event channels have a cpu hotplug callback. In order
to prepare for more percpu (de)init work move that callback into
events_base.c and add percpu_init() and percpu_deinit() hooks to
struct evtchn_ops.
This is part of XSA-332.
Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c44b849cee8c3ac587da3b0980e01f77500d158c upstream.
Instead of disabling the irq when an event is received and enabling
it again when handled by the user process use the lateeoi model.
This is part of XSA-332.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c2711441bc961b37bba0615dd7135857d189035f upstream.
In order to reduce the chance for the system becoming unresponsive due
to event storms triggered by a misbehaving pcifront use the lateeoi irq
binding for pciback and unmask the event channel only just before
leaving the event handling function.
Restructure the handling to support that scheme. Basically an event can
come in for two reasons: either a normal request for a pciback action,
which is handled in a worker, or in case the guest has finished an AER
request which was requested by pciback.
When an AER request is issued to the guest and a normal pciback action
is currently active issue an EOI early in order to be able to receive
another event when the AER request has been finished by the guest.
Let the worker processing the normal requests run until no further
request is pending, instead of starting a new worker ion that case.
Issue the EOI only just before leaving the worker.
This scheme allows to drop calling the generic function
xen_pcibk_test_and_schedule_op() after processing of any request as
the handling of both request types is now separated more cleanly.
This is part of XSA-332.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 86991b6e7ea6c613b7692f65106076943449b6b7 upstream.
In order to reduce the chance for the system becoming unresponsive due
to event storms triggered by a misbehaving scsifront use the lateeoi
irq binding for scsiback and unmask the event channel only just before
leaving the event handling function.
In case of a ring protocol error don't issue an EOI in order to avoid
the possibility to use that for producing an event storm. This at once
will result in no further call of scsiback_irq_fn(), so the ring_error
struct member can be dropped and scsiback_do_cmd_fn() can signal the
protocol error via a negative return value.
This is part of XSA-332.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 54c9de89895e0a36047fcc4ae754ea5b8655fb9d upstream.
In order to avoid tight event channel related IRQ loops add a new
framework of "late EOI" handling: the IRQ the event channel is bound
to will be masked until the event has been handled and the related
driver is capable to handle another event. The driver is responsible
for unmasking the event channel via the new function xen_irq_lateeoi().
This is similar to binding an event channel to a threaded IRQ, but
without having to structure the driver accordingly.
In order to support a future special handling in case a rogue guest
is sending lots of unsolicited events, add a flag to xen_irq_lateeoi()
which can be set by the caller to indicate the event was a spurious
one.
This is part of XSA-332.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f01337197419b7e8a492e83089552b77d3b5fb90 upstream.
Unmasking a fifo event channel can result in unmasking it twice, once
directly in the kernel and once via a hypercall in case the event was
pending.
Fix that by doing the local unmask only if the event is not pending.
This is part of XSA-332.
Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4d3fe31bd993ef504350989786858aefdb877daa upstream.
A follow-up patch will require certain write to happen before an event
channel is unmasked.
While the memory barrier is not strictly necessary for all the callers,
the main one will need it. In order to avoid an extra memory barrier
when using fifo event channels, mandate evtchn_unmask() to provide
write ordering.
The 2-level event handling unmask operation is missing an appropriate
barrier, so add it. Fifo event channels are fine in this regard due to
using sync_cmpxchg().
This is part of XSA-332.
Cc: stable@vger.kernel.org
Suggested-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 073d0552ead5bfc7a3a9c01de590e924f11b5dd2 upstream.
Today it can happen that an event channel is being removed from the
system while the event handling loop is active. This can lead to a
race resulting in crashes or WARN() splats when trying to access the
irq_info structure related to the event channel.
Fix this problem by using a rwlock taken as reader in the event
handling loop and as writer when deallocating the irq_info structure.
As the observed problem was a NULL dereference in evtchn_from_irq()
make this function more robust against races by testing the irq_info
pointer to be not NULL before dereferencing it.
And finally make all accesses to evtchn_to_irq[row][col] atomic ones
in order to avoid seeing partial updates of an array element in irq
handling. Note that irq handling can be entered only for event channels
which have been valid before, so any not populated row isn't a problem
in this regard, as rows are only ever added and never removed.
This is XSA-331.
Cc: stable@vger.kernel.org
Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reported-by: Jinoh Kang <luke1337@theori.io>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 0891fb39ba67bd7ae023ea0d367297ffff010781 upstream.
Since commit c330fb1ddc0a ("XEN uses irqdesc::irq_data_common::handler_data to store a per interrupt XEN data pointer which contains XEN specific information.")
Xen is using the chip_data pointer for storing IRQ specific data. When
running as a HVM domain this can result in problems for legacy IRQs, as
those might use chip_data for their own purposes.
Use a local array for this purpose in case of legacy IRQs, avoiding the
double use.
Cc: stable@vger.kernel.org
Fixes: c330fb1ddc0a ("XEN uses irqdesc::irq_data_common::handler_data to store a per interrupt XEN data pointer which contains XEN specific information.")
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Stefan Bader <stefan.bader@canonical.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20200930091614.13660-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
[bwh: Backported to 4.9: adjust context]
Signed-off-by: Ben Hutchings <benh@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit d742db70033c745e410523e00522ee0cfe2aa416 ]
On some architectures (like ARM), virt_to_gfn cannot be used for
vmalloc'd memory because of its reliance on virt_to_phys. This patch
introduces a check for vmalloc'd addresses and obtains the PFN using
vmalloc_to_pfn in that case.
Signed-off-by: Simon Leiner <simon@leiner.me>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20200825093153.35500-1-simon@leiner.me
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit c330fb1ddc0a922f044989492b7fcca77ee1db46 upstream.
handler data is meant for interrupt handlers and not for storing irq chip
specific information as some devices require handler data to store internal
per interrupt information, e.g. pinctrl/GPIO chained interrupt handlers.
This obviously creates a conflict of interests and crashes the machine
because the XEN pointer is overwritten by the driver pointer.
As the XEN data is not handler specific it should be stored in
irqdesc::irq_data::chip_data instead.
A simple sed s/irq_[sg]et_handler_data/irq_[sg]et_chip_data/ cures that.
Cc: stable@vger.kernel.org
Reported-by: Roman Shaposhnik <roman@zededa.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Roman Shaposhnik <roman@zededa.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/87lfi2yckt.fsf@nanos.tec.linutronix.de
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For support of long running hypercalls xen_maybe_preempt_hcall() is
calling cond_resched() in case a hypercall marked as preemptible has
been interrupted.
Normally this is no problem, as only hypercalls done via some ioctl()s
are marked to be preemptible. In rare cases when during such a
preemptible hypercall an interrupt occurs and any softirq action is
started from irq_exit(), a further hypercall issued by the softirq
handler will be regarded to be preemptible, too. This might lead to
rescheduling in spite of the softirq handler potentially having set
preempt_disable(), leading to splats like:
BUG: sleeping function called from invalid context at drivers/xen/preempt.c:37
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 20775, name: xl
INFO: lockdep is turned off.
CPU: 1 PID: 20775 Comm: xl Tainted: G D W 5.4.46-1_prgmr_debug.el7.x86_64 #1
Call Trace:
<IRQ>
dump_stack+0x8f/0xd0
___might_sleep.cold.76+0xb2/0x103
xen_maybe_preempt_hcall+0x48/0x70
xen_do_hypervisor_callback+0x37/0x40
RIP: e030:xen_hypercall_xen_version+0xa/0x20
Code: ...
RSP: e02b:ffffc900400dcc30 EFLAGS: 00000246
RAX: 000000000004000d RBX: 0000000000000200 RCX: ffffffff8100122a
RDX: ffff88812e788000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff83ee3ad0 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: ffff8881824aa0b0
R13: 0000000865496000 R14: 0000000865496000 R15: ffff88815d040000
? xen_hypercall_xen_version+0xa/0x20
? xen_force_evtchn_callback+0x9/0x10
? check_events+0x12/0x20
? xen_restore_fl_direct+0x1f/0x20
? _raw_spin_unlock_irqrestore+0x53/0x60
? debug_dma_sync_single_for_cpu+0x91/0xc0
? _raw_spin_unlock_irqrestore+0x53/0x60
? xen_swiotlb_sync_single_for_cpu+0x3d/0x140
? mlx4_en_process_rx_cq+0x6b6/0x1110 [mlx4_en]
? mlx4_en_poll_rx_cq+0x64/0x100 [mlx4_en]
? net_rx_action+0x151/0x4a0
? __do_softirq+0xed/0x55b
? irq_exit+0xea/0x100
? xen_evtchn_do_upcall+0x2c/0x40
? xen_do_hypervisor_callback+0x29/0x40
</IRQ>
? xen_hypercall_domctl+0xa/0x20
? xen_hypercall_domctl+0x8/0x20
? privcmd_ioctl+0x221/0x990 [xen_privcmd]
? do_vfs_ioctl+0xa5/0x6f0
? ksys_ioctl+0x60/0x90
? trace_hardirqs_off_thunk+0x1a/0x20
? __x64_sys_ioctl+0x16/0x20
? do_syscall_64+0x62/0x250
? entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fix that by testing preempt_count() before calling cond_resched().
In kernel 5.8 this can't happen any more due to the entry code rework
(more than 100 patches, so not a candidate for backporting).
The issue was introduced in kernel 4.3, so this patch should go into
all stable kernels in [4.3 ... 5.7].
Reported-by: Sarah Newman <srn@prgmr.com>
Fixes: 0fa2f5cb2b0ecd8 ("sched/preempt, xen: Use need_resched() instead of should_resched()")
Cc: Sarah Newman <srn@prgmr.com>
Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Chris Brannon <cmb@prgmr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 88a479ff6ef8af7f07e11593d58befc644244ff7 upstream.
So it can be killed, or else processes can get hung indefinitely
waiting for balloon pages.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200727091342.52325-3-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1951fa33ec259abdf3497bfee7b63e7ddbb1a394 upstream.
target_unpopulated is incremented with nr_pages at the start of the
function, but the call to free_xenballooned_pages will only subtract
pgno number of pages, and thus the rest need to be subtracted before
returning or else accounting will be skewed.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200727091342.52325-2-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
