Currently the I_DIRTY_TIME will never get set if the inode already has
I_DIRTY_INODE with assumption that it supersedes I_DIRTY_TIME. That's
true, however ext4 will only update the on-disk inode in
->dirty_inode(), not on actual writeback. As a result if the inode
already has I_DIRTY_INODE state by the time we get to
__mark_inode_dirty() only with I_DIRTY_TIME, the time was already filled
into on-disk inode and will not get updated until the next I_DIRTY_INODE
update, which might never come if we crash or get a power failure.
The problem can be reproduced on ext4 by running xfstest generic/622
with -o iversion mount option.
Fix it by allowing I_DIRTY_TIME to be set even if the inode already has
I_DIRTY_INODE. Also make sure that the case is properly handled in
writeback_single_inode() as well. Additionally changes in
xfs_fs_dirty_inode() was made to accommodate for I_DIRTY_TIME in flag.
Thanks Jan Kara for suggestions on how to make this work properly.
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220825100657.44217-1-lczerner@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
submit_bh/submit_bh_wbc are non-blocking functions which just submit
the bio and return. The caller of submit_bh/submit_bh_wbc needs to wait
on buffer till I/O completion and then check buffer head's b_state field
to know if there was any I/O error.
Hence there is no need for these functions to have any return type.
Even now they always returns 0. Hence drop the return value and make
their return type as void to avoid any confusion.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/cb66ef823374cdd94d2d03083ce13de844fffd41.1660788334.git.ritesh.list@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Pull tty/serial driver fixes from Greg KH:
"Here are some small tty/serial/vt driver fixes for 6.0-rc4 that
resolve a number of reported issues:
- n_gsm fixups for previous changes that caused problems
- much-reported serdev crash fix that showed up in 6.0-rc1
- vt font selection bugfix
- kerneldoc build warning fixes
- other tiny serial core fixes
All of these have been in linux-next for a while with no reported
problems"
* tag 'tty-6.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
tty: n_gsm: avoid call of sleeping functions from atomic context
tty: n_gsm: replace kicktimer with delayed_work
tty: n_gsm: initialize more members at gsm_alloc_mux()
tty: n_gsm: add sanity check for gsm->receive in gsm_receive_buf()
tty: serial: atmel: Preserve previous USART mode if RS485 disabled
tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete
tty: Fix lookahead_buf crash with serdev
serial: fsl_lpuart: RS485 RTS polariy is inverse
vt: Clear selection before changing the font
serial: document start_rx member at struct uart_ops
Pull io_uring fixes from Jens Axboe:
- A single fix for over-eager retries for networking (Pavel)
- Revert the notification slot support for zerocopy sends.
It turns out that even after more than a year or development and
testing, there's not full agreement on whether just using plain
ordered notifications is Good Enough to avoid the complexity of using
the notifications slots. Because of that, we decided that it's best
left to a future final decision.
We can always bring back this feature, but we can't really change it
or remove it once we've released 6.0 with it enabled. The reverts
leave the usual CQE notifications as the primary interface for
knowing when data was sent, and when it was acked. (Pavel)
* tag 'io_uring-6.0-2022-09-02' of git://git.kernel.dk/linux-block:
selftests/net: return back io_uring zc send tests
io_uring/net: simplify zerocopy send user API
io_uring/notif: remove notif registration
Revert "io_uring: rename IORING_OP_FILES_UPDATE"
Revert "io_uring: add zc notification flush requests"
selftests/net: temporarily disable io_uring zc test
io_uring/net: fix overexcessive retries
Pull driver core fixes from Greg KH:
"Here are some small driver core fixes for some oft-reported problems
in 6.0-rc1. They include:
- a bunch of reverts to handle driver_deferred_probe_check_state()
problems that were part of the 6.0-rc1 merge.
- firmware_loader bugfixes now that the code is being properly tested
and used by others
- arch_topology fix
- deferred driver probe bugfix to solve a long-suffering amba bus
problem that many people have reported.
All of these have been in linux-next for a while with no reported
problems"
* tag 'driver-core-6.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
firmware_loader: Fix memory leak in firmware upload
firmware_loader: Fix use-after-free during unregister
arch_topology: Silence early cacheinfo errors when non-existent
driver core: Don't probe devices after bus_type.match() probe deferral
Revert "iommu/of: Delete usage of driver_deferred_probe_check_state()"
Revert "PM: domains: Delete usage of driver_deferred_probe_check_state()"
Revert "net: mdio: Delete usage of driver_deferred_probe_check_state()"
Revert "driver core: Delete driver_deferred_probe_check_state()"
Pull USB/Thunderbolt driver fixes from Greg KH:
"Here are a lot of small USB and Thunderbolt driver fixes for 6.0-rc4
for reported problems. Included in here are:
- new usb-serial driver ids
- dwc3 driver bugfixes for reported problems with 6.0-rc1
- new device quirks, and reverts of some quirks that were incorrect
- gadget driver bugfixes for reported problems
- USB host controller bugfixes (xhci and others)
- other small USB fixes, details in the shortlog
- small thunderbolt driver fixes
All of these have been in linux-next with no reported issues"
* tag 'usb-6.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (51 commits)
Revert "usb: gadget: udc-xilinx: replace memcpy with memcpy_toio"
usb: storage: Add ASUS <0x0b05:0x1932> to IGNORE_UAS
USB: serial: ch341: fix disabled rx timer on older devices
USB: serial: ch341: fix lost character on LCR updates
USB: serial: cp210x: add Decagon UCA device id
Revert "usb: add quirks for Lenovo OneLink+ Dock"
usb: cdns3: fix issue with rearming ISO OUT endpoint
usb: cdns3: fix incorrect handling TRB_SMM flag for ISOC transfer
usb: gadget: mass_storage: Fix cdrom data transfers on MAC-OS
media: mceusb: Use new usb_control_msg_*() routines
USB: core: Prevent nested device-reset calls
USB: gadget: Fix obscure lockdep violation for udc_mutex
usb: dwc2: fix wrong order of phy_power_on and phy_init
usb: gadget: udc-xilinx: replace memcpy with memcpy_toio
usb: typec: Remove retimers properly
usb: dwc3: disable USB core PHY management
usb: add quirks for Lenovo OneLink+ Dock
USB: serial: option: add support for Cinterion MV32-WA/WB RmNet mode
USB: serial: ftdi_sio: add Omron CS1W-CIF31 device id
USB: serial: option: add Quectel EM060K modem
...
Pull x86 platform driver fixes from Hans de Goede:
"Various small fixes and hardware-id additions"
* tag 'platform-drivers-x86-v6.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86:
platform/x86: p2sb: Fix UAF when caller uses resource name
platform/x86: asus-wmi: Increase FAN_CURVE_BUF_LEN to 32
platform/mellanox: Remove redundant 'NULL' check
platform/mellanox: Remove unnecessary code
platform/mellanox: mlxreg-lc: Fix locking issue
platform/mellanox: mlxreg-lc: Fix coverity warning
platform/x86: acer-wmi: Acer Aspire One AOD270/Packard Bell Dot keymap fixes
platform/x86: thinkpad_acpi: Explicitly set to balanced mode on startup
platform/x86: asus-wmi: Fix the name of the mic-mute LED classdev
platform/surface: aggregator_registry: Add HID devices for sensors and UCSI client to SP8
platform/surface: aggregator_registry: Rename HID device nodes based on new findings
platform/surface: aggregator_registry: Rename HID device nodes based on their function
platform/surface: aggregator_registry: Add support for Surface Laptop Go 2
platform/x86: x86-android-tablets: Fix broken touchscreen on Chuwi Hi8 with Windows BIOS
platform/x86: pmc_atom: Fix SLP_TYPx bitfield mask
Pull networking fixes from Paolo Abeni:
"Including fixes from bluetooth, bpf and wireless.
Current release - regressions:
- bpf:
- fix wrong last sg check in sk_msg_recvmsg()
- fix kernel BUG in purge_effective_progs()
- mac80211:
- fix possible leak in ieee80211_tx_control_port()
- potential NULL dereference in ieee80211_tx_control_port()
Current release - new code bugs:
- nfp: fix the access to management firmware hanging
Previous releases - regressions:
- ip: fix triggering of 'icmp redirect'
- sched: tbf: don't call qdisc_put() while holding tree lock
- bpf: fix corrupted packets for XDP_SHARED_UMEM
- bluetooth: hci_sync: fix suspend performance regression
- micrel: fix probe failure
Previous releases - always broken:
- tcp: make global challenge ack rate limitation per net-ns and
default disabled
- tg3: fix potential hang-up on system reboot
- mac802154: fix reception for no-daddr packets
Misc:
- r8152: add PID for the lenovo onelink+ dock"
* tag 'net-6.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (56 commits)
net/smc: Remove redundant refcount increase
Revert "sch_cake: Return __NET_XMIT_STOLEN when consuming enqueued skb"
tcp: make global challenge ack rate limitation per net-ns and default disabled
tcp: annotate data-race around challenge_timestamp
net: dsa: hellcreek: Print warning only once
ip: fix triggering of 'icmp redirect'
sch_cake: Return __NET_XMIT_STOLEN when consuming enqueued skb
selftests: net: sort .gitignore file
Documentation: networking: correct possessive "its"
kcm: fix strp_init() order and cleanup
mlxbf_gige: compute MDIO period based on i1clk
ethernet: rocker: fix sleep in atomic context bug in neigh_timer_handler
net: lan966x: improve error handle in lan966x_fdma_rx_get_frame()
nfp: fix the access to management firmware hanging
net: phy: micrel: Make the GPIO to be non-exclusive
net: virtio_net: fix notification coalescing comments
net/sched: fix netdevice reference leaks in attach_default_qdiscs()
net: sched: tbf: don't call qdisc_put() while holding tree lock
net: Use u64_stats_fetch_begin_irq() for stats fetch.
net: dsa: xrs700x: Use irqsave variant for u64 stats update
...
Following user feedback, this patch simplifies zerocopy send API. One of
the main complaints is that the current API is difficult with the
userspace managing notification slots, and then send retries with error
handling make it even worse.
Instead of keeping notification slots change it to the per-request
notifications model, which posts both completion and notification CQEs
for each request when any data has been sent, and only one CQE if it
fails. All notification CQEs will have IORING_CQE_F_NOTIF set and
IORING_CQE_F_MORE in completion CQEs indicates whether to wait a
notification or not.
IOSQE_CQE_SKIP_SUCCESS is disallowed with zerocopy sends for now.
This is less flexible, but greatly simplifies the user API and also the
kernel implementation. We reuse notif helpers in this patch, but in the
future there won't be need for keeping two requests.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/95287640ab98fc9417370afb16e310677c63e6ce.1662027856.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Because per host rate limiting has been proven problematic (side channel
attacks can be based on it), per host rate limiting of challenge acks ideally
should be per netns and turned off by default.
This is a long due followup of following commits:
083ae30828 ("tcp: enable per-socket rate limiting of all 'challenge acks'")
f2b2c582e8 ("tcp: mitigate ACK loops for connections as tcp_sock")
75ff39ccc1 ("tcp: make challenge acks less predictable")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jason Baron <jbaron@akamai.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
anon_vma->degree tracks the combined number of child anon_vmas and VMAs
that use the anon_vma as their ->anon_vma.
anon_vma_clone() then assumes that for any anon_vma attached to
src->anon_vma_chain other than src->anon_vma, it is impossible for it to
be a leaf node of the VMA tree, meaning that for such VMAs ->degree is
elevated by 1 because of a child anon_vma, meaning that if ->degree
equals 1 there are no VMAs that use the anon_vma as their ->anon_vma.
This assumption is wrong because the ->degree optimization leads to leaf
nodes being abandoned on anon_vma_clone() - an existing anon_vma is
reused and no new parent-child relationship is created. So it is
possible to reuse an anon_vma for one VMA while it is still tied to
another VMA.
This is an issue because is_mergeable_anon_vma() and its callers assume
that if two VMAs have the same ->anon_vma, the list of anon_vmas
attached to the VMAs is guaranteed to be the same. When this assumption
is violated, vma_merge() can merge pages into a VMA that is not attached
to the corresponding anon_vma, leading to dangling page->mapping
pointers that will be dereferenced during rmap walks.
Fix it by separately tracking the number of child anon_vmas and the
number of VMAs using the anon_vma as their ->anon_vma.
Fixes: 7a3ef208e6 ("mm: prevent endless growth of anon_vma hierarchy")
Cc: stable@kernel.org
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull fscache/cachefiles fixes from David Howells:
- Fix kdoc on fscache_use/unuse_cookie().
- Fix the error returned by cachefiles_ondemand_copen() from an upcall
result.
- Fix the distribution of requests in on-demand mode in cachefiles to
be fairer by cycling through them rather than picking the one with
the lowest ID each time (IDs being reused).
* tag 'fscache-fixes-20220831' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
cachefiles: make on-demand request distribution fairer
cachefiles: fix error return code in cachefiles_ondemand_copen()
fscache: fix misdocumented parameter
Pull LSM support for IORING_OP_URING_CMD from Paul Moore:
"Add SELinux and Smack controls to the io_uring IORING_OP_URING_CMD.
These are necessary as without them the IORING_OP_URING_CMD remains
outside the purview of the LSMs (Luis' LSM patch, Casey's Smack patch,
and my SELinux patch). They have been discussed at length with the
io_uring folks, and Jens has given his thumbs-up on the relevant
patches (see the commit descriptions).
There is one patch that is not strictly necessary, but it makes
testing much easier and is very trivial: the /dev/null
IORING_OP_URING_CMD patch."
* tag 'lsm-pr-20220829' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
Smack: Provide read control for io_uring_cmd
/dev/null: add IORING_OP_URING_CMD support
selinux: implement the security_uring_cmd() LSM hook
lsm,io_uring: add LSM hooks for the new uring_cmd file op
Automatic kernel fuzzing revealed a recursive locking violation in
usb-storage:
============================================
WARNING: possible recursive locking detected
5.18.0 #3 Not tainted
--------------------------------------------
kworker/1:3/1205 is trying to acquire lock:
ffff888018638db8 (&us_interface_key[i]){+.+.}-{3:3}, at:
usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230
but task is already holding lock:
ffff888018638db8 (&us_interface_key[i]){+.+.}-{3:3}, at:
usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230
...
stack backtrace:
CPU: 1 PID: 1205 Comm: kworker/1:3 Not tainted 5.18.0 #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_deadlock_bug kernel/locking/lockdep.c:2988 [inline]
check_deadlock kernel/locking/lockdep.c:3031 [inline]
validate_chain kernel/locking/lockdep.c:3816 [inline]
__lock_acquire.cold+0x152/0x3ca kernel/locking/lockdep.c:5053
lock_acquire kernel/locking/lockdep.c:5665 [inline]
lock_acquire+0x1ab/0x520 kernel/locking/lockdep.c:5630
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x14f/0x1610 kernel/locking/mutex.c:747
usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230
usb_reset_device+0x37d/0x9a0 drivers/usb/core/hub.c:6109
r871xu_dev_remove+0x21a/0x270 drivers/staging/rtl8712/usb_intf.c:622
usb_unbind_interface+0x1bd/0x890 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:545 [inline]
device_remove+0x11f/0x170 drivers/base/dd.c:537
__device_release_driver drivers/base/dd.c:1222 [inline]
device_release_driver_internal+0x1a7/0x2f0 drivers/base/dd.c:1248
usb_driver_release_interface+0x102/0x180 drivers/usb/core/driver.c:627
usb_forced_unbind_intf+0x4d/0xa0 drivers/usb/core/driver.c:1118
usb_reset_device+0x39b/0x9a0 drivers/usb/core/hub.c:6114
This turned out not to be an error in usb-storage but rather a nested
device reset attempt. That is, as the rtl8712 driver was being
unbound from a composite device in preparation for an unrelated USB
reset (that driver does not have pre_reset or post_reset callbacks),
its ->remove routine called usb_reset_device() -- thus nesting one
reset call within another.
Performing a reset as part of disconnect processing is a questionable
practice at best. However, the bug report points out that the USB
core does not have any protection against nested resets. Adding a
reset_in_progress flag and testing it will prevent such errors in the
future.
Link: https://lore.kernel.org/all/CAB7eexKUpvX-JNiLzhXBDWgfg2T9e9_0Tw4HQ6keN==voRbP0g@mail.gmail.com/
Cc: stable@vger.kernel.org
Reported-and-tested-by: Rondreis <linhaoguo86@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/YwkflDxvg0KWqyZK@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull more hotfixes from Andrew Morton:
"Seventeen hotfixes. Mostly memory management things.
Ten patches are cc:stable, addressing pre-6.0 issues"
* tag 'mm-hotfixes-stable-2022-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
.mailmap: update Luca Ceresoli's e-mail address
mm/mprotect: only reference swap pfn page if type match
squashfs: don't call kmalloc in decompressors
mm/damon/dbgfs: avoid duplicate context directory creation
mailmap: update email address for Colin King
asm-generic: sections: refactor memory_intersects
bootmem: remove the vmemmap pages from kmemleak in put_page_bootmem
ocfs2: fix freeing uninitialized resource on ocfs2_dlm_shutdown
Revert "memcg: cleanup racy sum avoidance code"
mm/zsmalloc: do not attempt to free IS_ERR handle
binder_alloc: add missing mmap_lock calls when using the VMA
mm: re-allow pinning of zero pfns (again)
vmcoreinfo: add kallsyms_num_syms symbol
mailmap: update Guilherme G. Piccoli's email addresses
writeback: avoid use-after-free after removing device
shmem: update folio if shmem_replace_page() updates the page
mm/hugetlb: avoid corrupting page->mapping in hugetlb_mcopy_atomic_pte
There are two problems with the current code of memory_intersects:
First, it doesn't check whether the region (begin, end) falls inside the
region (virt, vend), that is (virt < begin && vend > end).
The second problem is if vend is equal to begin, it will return true but
this is wrong since vend (virt + size) is not the last address of the
memory region but (virt + size -1) is. The wrong determination will
trigger the misreporting when the function check_for_illegal_area calls
memory_intersects to check if the dma region intersects with stext region.
The misreporting is as below (stext is at 0x80100000):
WARNING: CPU: 0 PID: 77 at kernel/dma/debug.c:1073 check_for_illegal_area+0x130/0x168
DMA-API: chipidea-usb2 e0002000.usb: device driver maps memory from kernel text or rodata [addr=800f0000] [len=65536]
Modules linked in:
CPU: 1 PID: 77 Comm: usb-storage Not tainted 5.19.0-yocto-standard #5
Hardware name: Xilinx Zynq Platform
unwind_backtrace from show_stack+0x18/0x1c
show_stack from dump_stack_lvl+0x58/0x70
dump_stack_lvl from __warn+0xb0/0x198
__warn from warn_slowpath_fmt+0x80/0xb4
warn_slowpath_fmt from check_for_illegal_area+0x130/0x168
check_for_illegal_area from debug_dma_map_sg+0x94/0x368
debug_dma_map_sg from __dma_map_sg_attrs+0x114/0x128
__dma_map_sg_attrs from dma_map_sg_attrs+0x18/0x24
dma_map_sg_attrs from usb_hcd_map_urb_for_dma+0x250/0x3b4
usb_hcd_map_urb_for_dma from usb_hcd_submit_urb+0x194/0x214
usb_hcd_submit_urb from usb_sg_wait+0xa4/0x118
usb_sg_wait from usb_stor_bulk_transfer_sglist+0xa0/0xec
usb_stor_bulk_transfer_sglist from usb_stor_bulk_srb+0x38/0x70
usb_stor_bulk_srb from usb_stor_Bulk_transport+0x150/0x360
usb_stor_Bulk_transport from usb_stor_invoke_transport+0x38/0x440
usb_stor_invoke_transport from usb_stor_control_thread+0x1e0/0x238
usb_stor_control_thread from kthread+0xf8/0x104
kthread from ret_from_fork+0x14/0x2c
Refactor memory_intersects to fix the two problems above.
Before the 1d7db834a0 ("dma-debug: use memory_intersects()
directly"), memory_intersects is called only by printk_late_init:
printk_late_init -> init_section_intersects ->memory_intersects.
There were few places where memory_intersects was called.
When commit 1d7db834a0 ("dma-debug: use memory_intersects()
directly") was merged and CONFIG_DMA_API_DEBUG is enabled, the DMA
subsystem uses it to check for an illegal area and the calltrace above
is triggered.
[akpm@linux-foundation.org: fix nearby comment typo]
Link: https://lkml.kernel.org/r/20220819081145.948016-1-quanyang.wang@windriver.com
Fixes: 9795593625 ("asm/sections: add helpers to check for section data")
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thierry Reding <treding@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This reverts commit 96e51ccf1a.
Recently we started running the kernel with rstat infrastructure on
production traffic and begin to see negative memcg stats values.
Particularly the 'sock' stat is the one which we observed having negative
value.
$ grep "sock " /mnt/memory/job/memory.stat
sock 253952
total_sock 18446744073708724224
Re-run after couple of seconds
$ grep "sock " /mnt/memory/job/memory.stat
sock 253952
total_sock 53248
For now we are only seeing this issue on large machines (256 CPUs) and
only with 'sock' stat. I think the networking stack increase the stat on
one cpu and decrease it on another cpu much more often. So, this negative
sock is due to rstat flusher flushing the stats on the CPU that has seen
the decrement of sock but missed the CPU that has increments. A typical
race condition.
For easy stable backport, revert is the most simple solution. For long
term solution, I am thinking of two directions. First is just reduce the
race window by optimizing the rstat flusher. Second is if the reader sees
a negative stat value, force flush and restart the stat collection.
Basically retry but limited.
Link: https://lkml.kernel.org/r/20220817172139.3141101-1-shakeelb@google.com
Fixes: 96e51ccf1a ("memcg: cleanup racy sum avoidance code")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: <stable@vger.kernel.org> [5.15]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull io_uring fixes from Jens Axboe:
- Add missing header file to the MAINTAINERS entry for io_uring (Ammar)
- liburing and the kernel ship the same io_uring.h header, but one
change we've had for a long time only in liburing is to ensure it's
C++ safe. Add extern C around it, so we can more easily sync them in
the future (Ammar)
- Fix an off-by-one in the sync cancel added in this merge window (me)
- Error handling fix for passthrough (Kanchan)
- Fix for address saving for async execution for the zc tx support
(Pavel)
- Fix ordering for TCP zc notifications, so we always have them ordered
correctly between "data was sent" and "data was acked". This isn't
strictly needed with the notification slots, but we've been pondering
disabling the slot support for 6.0 - and if we do, then we do require
the ordering to be sane. Regardless of that, it's the sane thing to
do in terms of API (Pavel)
- Minor cleanup for indentation and lockdep annotation (Pavel)
* tag 'io_uring-6.0-2022-08-26' of git://git.kernel.dk/linux-block:
io_uring/net: save address for sendzc async execution
io_uring: conditional ->async_data allocation
io_uring/notif: order notif vs send CQEs
io_uring/net: fix indentation
io_uring/net: fix zc send link failing
io_uring/net: fix must_hold annotation
io_uring: fix submission-failure handling for uring-cmd
io_uring: fix off-by-one in sync cancelation file check
io_uring: uapi: Add `extern "C"` in io_uring.h for liburing
MAINTAINERS: Add `include/linux/io_uring_types.h`
Pull SCSI fixes from James Bottomley:
"Ten fixes.
Of the three core changes, the two large ones are a complete reversion
of the async rework and an ALUA timing rework (the latter shouldn't
affect non-ALUA paths).
The remaining patches are all small and all but one in drivers"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: sd: Revert "Rework asynchronous resume support"
scsi: core: Fix passthrough retry counter handling
scsi: ufs: core: Reduce the power mode change timeout
scsi: storvsc: Remove WQ_MEM_RECLAIM from storvsc_error_wq
scsi: ufs: host: ufs-exynos: Make fsd_ufs_drvs static
scsi: megaraid_sas: Remove unnecessary kfree()
scsi: megaraid_sas: Fix double kfree()
scsi: ufs: core: Enable link lost interrupt
scsi: core: Allow the ALUA transitioning state enough time
scsi: qla2xxx: Disable ATIO interrupt coalesce for quad port ISP27XX
There are several places in the kernel where wait_on_bit is not followed
by a memory barrier (for example, in drivers/md/dm-bufio.c:new_read).
On architectures with weak memory ordering, it may happen that memory
accesses that follow wait_on_bit are reordered before wait_on_bit and
they may return invalid data.
Fix this class of bugs by introducing a new function "test_bit_acquire"
that works like test_bit, but has acquire memory ordering semantics.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
io-uring cmd support was added through ee692a21e9 ("fs,io_uring:
add infrastructure for uring-cmd"), this extended the struct
file_operations to allow a new command which each subsystem can use
to enable command passthrough. Add an LSM specific for the command
passthrough which enables LSMs to inspect the command details.
This was discussed long ago without no clear pointer for something
conclusive, so this enables LSMs to at least reject this new file
operation.
[0] https://lkml.kernel.org/r/8adf55db-7bab-f59d-d612-ed906b948d19@schaufler-ca.com
Cc: stable@vger.kernel.org
Fixes: ee692a21e9 ("fs,io_uring: add infrastructure for uring-cmd")
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Daniel borkmann says:
====================
The following pull-request contains BPF updates for your *net* tree.
We've added 11 non-merge commits during the last 14 day(s) which contain
a total of 13 files changed, 61 insertions(+), 24 deletions(-).
The main changes are:
1) Fix BPF verifier's precision tracking around BPF ring buffer, from Kumar Kartikeya Dwivedi.
2) Fix regression in tunnel key infra when passing FLOWI_FLAG_ANYSRC, from Eyal Birger.
3) Fix insufficient permissions for bpf_sys_bpf() helper, from YiFei Zhu.
4) Fix splat from hitting BUG when purging effective cgroup programs, from Pu Lehui.
5) Fix range tracking for array poke descriptors, from Daniel Borkmann.
6) Fix corrupted packets for XDP_SHARED_UMEM in aligned mode, from Magnus Karlsson.
7) Fix NULL pointer splat in BPF sockmap sk_msg_recvmsg(), from Liu Jian.
8) Add READ_ONCE() to bpf_jit_limit when reading from sysctl, from Kuniyuki Iwashima.
9) Add BPF selftest lru_bug check to s390x deny list, from Daniel Müller.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking fixes from Jakub Kicinski:
"Including fixes from ipsec and netfilter (with one broken Fixes tag).
Current release - new code bugs:
- dsa: don't dereference NULL extack in dsa_slave_changeupper()
- dpaa: fix <1G ethernet on LS1046ARDB
- neigh: don't call kfree_skb() under spin_lock_irqsave()
Previous releases - regressions:
- r8152: fix the RX FIFO settings when suspending
- dsa: microchip: keep compatibility with device tree blobs with no
phy-mode
- Revert "net: macsec: update SCI upon MAC address change."
- Revert "xfrm: update SA curlft.use_time", comply with RFC 2367
Previous releases - always broken:
- netfilter: conntrack: work around exceeded TCP receive window
- ipsec: fix a null pointer dereference of dst->dev on a metadata dst
in xfrm_lookup_with_ifid
- moxa: get rid of asymmetry in DMA mapping/unmapping
- dsa: microchip: make learning configurable and keep it off while
standalone
- ice: xsk: prohibit usage of non-balanced queue id
- rxrpc: fix locking in rxrpc's sendmsg
Misc:
- another chunk of sysctl data race silencing"
* tag 'net-6.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (87 commits)
net: lantiq_xrx200: restore buffer if memory allocation failed
net: lantiq_xrx200: fix lock under memory pressure
net: lantiq_xrx200: confirm skb is allocated before using
net: stmmac: work around sporadic tx issue on link-up
ionic: VF initial random MAC address if no assigned mac
ionic: fix up issues with handling EAGAIN on FW cmds
ionic: clear broken state on generation change
rxrpc: Fix locking in rxrpc's sendmsg
net: ethernet: mtk_eth_soc: fix hw hash reporting for MTK_NETSYS_V2
MAINTAINERS: rectify file entry in BONDING DRIVER
i40e: Fix incorrect address type for IPv6 flow rules
ixgbe: stop resetting SYSTIME in ixgbe_ptp_start_cyclecounter
net: Fix a data-race around sysctl_somaxconn.
net: Fix a data-race around netdev_unregister_timeout_secs.
net: Fix a data-race around gro_normal_batch.
net: Fix data-races around sysctl_devconf_inherit_init_net.
net: Fix data-races around sysctl_fb_tunnels_only_for_init_net.
net: Fix a data-race around netdev_budget_usecs.
net: Fix data-races around sysctl_max_skb_frags.
net: Fix a data-race around netdev_budget.
...
Pablo Neira Ayuso says:
====================
Netfilter fixes for net
1) Fix crash with malformed ebtables blob which do not provide all
entry points, from Florian Westphal.
2) Fix possible TCP connection clogging up with default 5-days
timeout in conntrack, from Florian.
3) Fix crash in nf_tables tproxy with unsupported chains, also from Florian.
4) Do not allow to update implicit chains.
5) Make table handle allocation per-netns to fix data race.
6) Do not truncated payload length and offset, and checksum offset.
Instead report EINVAl.
7) Enable chain stats update via static key iff no error occurs.
8) Restrict osf expression to ip, ip6 and inet families.
9) Restrict tunnel expression to netdev family.
10) Fix crash when trying to bind again an already bound chain.
11) Flowtable garbage collector might leave behind pending work to
delete entries. This patch comes with a previous preparation patch
as dependency.
12) Allow net.netfilter.nf_conntrack_frag6_high_thresh to be lowered,
from Eric Dumazet.
* git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
netfilter: nf_defrag_ipv6: allow nf_conntrack_frag6_high_thresh increases
netfilter: flowtable: fix stuck flows on cleanup due to pending work
netfilter: flowtable: add function to invoke garbage collection immediately
netfilter: nf_tables: disallow binding to already bound chain
netfilter: nft_tunnel: restrict it to netdev family
netfilter: nft_osf: restrict osf to ipv4, ipv6 and inet families
netfilter: nf_tables: do not leave chain stats enabled on error
netfilter: nft_payload: do not truncate csum_offset and csum_type
netfilter: nft_payload: report ERANGE for too long offset and length
netfilter: nf_tables: make table handle allocation per-netns friendly
netfilter: nf_tables: disallow updates of implicit chain
netfilter: nft_tproxy: restrict to prerouting hook
netfilter: conntrack: work around exceeded receive window
netfilter: ebtables: reject blobs that don't provide all entry points
====================
Link: https://lore.kernel.org/r/20220824220330.64283-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
While reading gro_normal_batch, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.
Fixes: 323ebb61e3 ("net: use listified RX for handling GRO_NORMAL skbs")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While reading sysctl_devconf_inherit_init_net, it can be changed
concurrently. Thus, we need to add READ_ONCE() to its readers.
Fixes: 856c395cfa ("net: introduce a knob to control whether to inherit devconf config")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While reading sysctl_fb_tunnels_only_for_init_net, it can be changed
concurrently. Thus, we need to add READ_ONCE() to its readers.
Fixes: 79134e6ce2 ("net: do not create fallback tunnels for non-default namespaces")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While reading sysctl_net_busy_poll, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.
Fixes: 0602129286 ("net: add low latency socket poll")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Steffen Klassert says:
====================
pull request (net): ipsec 2022-08-24
1) Fix a refcount leak in __xfrm_policy_check.
From Xin Xiong.
2) Revert "xfrm: update SA curlft.use_time". This
violates RFC 2367. From Antony Antony.
3) Fix a comment on XFRMA_LASTUSED.
From Antony Antony.
4) x->lastused is not cloned in xfrm_do_migrate.
Fix from Antony Antony.
5) Serialize the calls to xfrm_probe_algs.
From Herbert Xu.
6) Fix a null pointer dereference of dst->dev on a metadata
dst in xfrm_lookup_with_ifid. From Nikolay Aleksandrov.
Please pull or let me know if there are problems.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
To clear the flow table on flow table free, the following sequence
normally happens in order:
1) gc_step work is stopped to disable any further stats/del requests.
2) All flow table entries are set to teardown state.
3) Run gc_step which will queue HW del work for each flow table entry.
4) Waiting for the above del work to finish (flush).
5) Run gc_step again, deleting all entries from the flow table.
6) Flow table is freed.
But if a flow table entry already has pending HW stats or HW add work
step 3 will not queue HW del work (it will be skipped), step 4 will wait
for the pending add/stats to finish, and step 5 will queue HW del work
which might execute after freeing of the flow table.
To fix the above, this patch flushes the pending work, then it sets the
teardown flag to all flows in the flowtable and it forces a garbage
collector run to queue work to remove the flows from hardware, then it
flushes this new pending work and (finally) it forces another garbage
collector run to remove the entry from the software flowtable.
Stack trace:
[47773.882335] BUG: KASAN: use-after-free in down_read+0x99/0x460
[47773.883634] Write of size 8 at addr ffff888103b45aa8 by task kworker/u20:6/543704
[47773.885634] CPU: 3 PID: 543704 Comm: kworker/u20:6 Not tainted 5.12.0-rc7+ #2
[47773.886745] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)
[47773.888438] Workqueue: nf_ft_offload_del flow_offload_work_handler [nf_flow_table]
[47773.889727] Call Trace:
[47773.890214] dump_stack+0xbb/0x107
[47773.890818] print_address_description.constprop.0+0x18/0x140
[47773.892990] kasan_report.cold+0x7c/0xd8
[47773.894459] kasan_check_range+0x145/0x1a0
[47773.895174] down_read+0x99/0x460
[47773.899706] nf_flow_offload_tuple+0x24f/0x3c0 [nf_flow_table]
[47773.907137] flow_offload_work_handler+0x72d/0xbe0 [nf_flow_table]
[47773.913372] process_one_work+0x8ac/0x14e0
[47773.921325]
[47773.921325] Allocated by task 592159:
[47773.922031] kasan_save_stack+0x1b/0x40
[47773.922730] __kasan_kmalloc+0x7a/0x90
[47773.923411] tcf_ct_flow_table_get+0x3cb/0x1230 [act_ct]
[47773.924363] tcf_ct_init+0x71c/0x1156 [act_ct]
[47773.925207] tcf_action_init_1+0x45b/0x700
[47773.925987] tcf_action_init+0x453/0x6b0
[47773.926692] tcf_exts_validate+0x3d0/0x600
[47773.927419] fl_change+0x757/0x4a51 [cls_flower]
[47773.928227] tc_new_tfilter+0x89a/0x2070
[47773.936652]
[47773.936652] Freed by task 543704:
[47773.937303] kasan_save_stack+0x1b/0x40
[47773.938039] kasan_set_track+0x1c/0x30
[47773.938731] kasan_set_free_info+0x20/0x30
[47773.939467] __kasan_slab_free+0xe7/0x120
[47773.940194] slab_free_freelist_hook+0x86/0x190
[47773.941038] kfree+0xce/0x3a0
[47773.941644] tcf_ct_flow_table_cleanup_work
Original patch description and stack trace by Paul Blakey.
Fixes: c29f74e0df ("netfilter: nf_flow_table: hardware offload support")
Reported-by: Paul Blakey <paulb@nvidia.com>
Tested-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pull cgroup fixes from Tejun Heo:
- The psi data structure was changed to be allocated dynamically but
it wasn't being cleared leading to it reporting garbage values and
triggering spurious oom kills.
- A deadlock involving cpuset and cpu hotplug.
- When a controller is moved across cgroup hierarchies,
css->rstat_css_node didn't get RCU drained properly from the previous
list.
* tag 'cgroup-for-6.0-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: Fix race condition at rebind_subsystems()
cgroup: Fix threadgroup_rwsem <-> cpus_read_lock() deadlock
sched/psi: Remove redundant cgroup_psi() when !CONFIG_CGROUPS
sched/psi: Remove unused parameter nbytes of psi_trigger_create()
sched/psi: Zero the memory of struct psi_group
Saeed Mahameed says:
====================
mlx5 fixes 2022-08-22
This series provides bug fixes to mlx5 driver.
* tag 'mlx5-fixes-2022-08-22' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux:
net/mlx5: Unlock on error in mlx5_sriov_enable()
net/mlx5e: Fix use after free in mlx5e_fs_init()
net/mlx5e: kTLS, Use _safe() iterator in mlx5e_tls_priv_tx_list_cleanup()
net/mlx5: unlock on error path in esw_vfs_changed_event_handler()
net/mlx5e: Fix wrong tc flag used when set hw-tc-offload off
net/mlx5e: TC, Add missing policer validation
net/mlx5e: Fix wrong application of the LRO state
net/mlx5: Avoid false positive lockdep warning by adding lock_class_key
net/mlx5: Fix cmd error logging for manage pages cmd
net/mlx5: Disable irq when locking lag_lock
net/mlx5: Eswitch, Fix forwarding decision to uplink
net/mlx5: LAG, fix logic over MLX5_LAG_FLAG_NDEVS_READY
net/mlx5e: Properly disable vlan strip on non-UL reps
====================
Link: https://lore.kernel.org/r/20220822195917.216025-1-saeed@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull misc fixes from Andrew Morton:
"Thirteen fixes, almost all for MM.
Seven of these are cc:stable and the remainder fix up the changes
which went into this -rc cycle"
* tag 'mm-hotfixes-stable-2022-08-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
kprobes: don't call disarm_kprobe() for disabled kprobes
mm/shmem: shmem_replace_page() remember NR_SHMEM
mm/shmem: tmpfs fallocate use file_modified()
mm/shmem: fix chattr fsflags support in tmpfs
mm/hugetlb: support write-faults in shared mappings
mm/hugetlb: fix hugetlb not supporting softdirty tracking
mm/uffd: reset write protection when unregister with wp-mode
mm/smaps: don't access young/dirty bit if pte unpresent
mm: add DEVICE_ZONE to FOR_ALL_ZONES
kernel/sys_ni: add compat entry for fadvise64_64
mm/gup: fix FOLL_FORCE COW security issue and remove FOLL_COW
Revert "zram: remove double compression logic"
get_maintainer: add Alan to .get_maintainer.ignore
Harshit Mogalapalli says:
In ebt_do_table() function dereferencing 'private->hook_entry[hook]'
can lead to NULL pointer dereference. [..] Kernel panic:
general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
[..]
RIP: 0010:ebt_do_table+0x1dc/0x1ce0
Code: 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 5c 16 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 6c df 08 48 8d 7d 2c 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 88
[..]
Call Trace:
nf_hook_slow+0xb1/0x170
__br_forward+0x289/0x730
maybe_deliver+0x24b/0x380
br_flood+0xc6/0x390
br_dev_xmit+0xa2e/0x12c0
For some reason ebtables rejects blobs that provide entry points that are
not supported by the table, but what it should instead reject is the
opposite: blobs that DO NOT provide an entry point supported by the table.
t->valid_hooks is the bitmask of hooks (input, forward ...) that will see
packets. Providing an entry point that is not support is harmless
(never called/used), but the inverse isn't: it results in a crash
because the ebtables traverser doesn't expect a NULL blob for a location
its receiving packets for.
Instead of fixing all the individual checks, do what iptables is doing and
reject all blobs that differ from the expected hooks.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
The value is only ever set once in bond_3ad_initialize and only ever
read otherwise. There seems to be no reason to set the variable via
bond_3ad_initialize when setting the global variable will do. Change
ad_ticks_per_sec to a const to enforce its read-only usage.
Signed-off-by: Jonathan Toppins <jtoppins@redhat.com>
Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull NFS client fixes from Trond Myklebust:
"Stable fixes:
- NFS: Fix another fsync() issue after a server reboot
Bugfixes:
- NFS: unlink/rmdir shouldn't call d_delete() twice on ENOENT
- NFS: Fix missing unlock in nfs_unlink()
- Add sanity checking of the file type used by __nfs42_ssc_open
- Fix a case where we're failing to set task->tk_rpc_status
Cleanups:
- Remove the NFS_CONTEXT_RESEND_WRITES flag that got obsoleted by the
fsync() fix"
* tag 'nfs-for-5.20-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
SUNRPC: RPC level errors should set task->tk_rpc_status
NFSv4.2 fix problems with __nfs42_ssc_open
NFS: unlink/rmdir shouldn't call d_delete() twice on ENOENT
NFS: Cleanup to remove unused flag NFS_CONTEXT_RESEND_WRITES
NFS: Remove a bogus flag setting in pnfs_write_done_resend_to_mds
NFS: Fix another fsync() issue after a server reboot
NFS: Fix missing unlock in nfs_unlink()
ext[234] have always allowed unimplemented chattr flags to be set, but
other filesystems have tended to be stricter. Follow the stricter
approach for tmpfs: I don't want to have to explain why csu attributes
don't actually work, and we won't need to update the chattr(1) manpage;
and it's never wrong to start off strict, relaxing later if persuaded.
Allow only a (append only) i (immutable) A (no atime) and d (no dump).
Although lsattr showed 'A' inherited, the NOATIME behavior was not being
inherited: because nothing sync'ed FS_NOATIME_FL to S_NOATIME. Add
shmem_set_inode_flags() to sync the flags, using inode_set_flags() to
avoid that instant of lost immutablility during fileattr_set().
But that change switched generic/079 from passing to failing: because
FS_IMMUTABLE_FL and FS_APPEND_FL had been unconventionally included in the
INHERITED fsflags: remove them and generic/079 is back to passing.
Link: https://lkml.kernel.org/r/2961dcb0-ddf3-b9f0-3268-12a4ff996856@google.com
Fixes: e408e695f5 ("mm/shmem: support FS_IOC_[SG]ETFLAGS in tmpfs")
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Radoslaw Burny <rburny@google.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The motivation of this patch comes from a recent report and patchfix from
David Hildenbrand on hugetlb shared handling of wr-protected page [1].
With the reproducer provided in commit message of [1], one can leverage
the uffd-wp lazy-reset of ptes to trigger a hugetlb issue which can affect
not only the attacker process, but also the whole system.
The lazy-reset mechanism of uffd-wp was used to make unregister faster,
meanwhile it has an assumption that any leftover pgtable entries should
only affect the process on its own, so not only the user should be aware
of anything it does, but also it should not affect outside of the process.
But it seems that this is not true, and it can also be utilized to make
some exploit easier.
So far there's no clue showing that the lazy-reset is important to any
userfaultfd users because normally the unregister will only happen once
for a specific range of memory of the lifecycle of the process.
Considering all above, what this patch proposes is to do explicit pte
resets when unregister an uffd region with wr-protect mode enabled.
It should be the same as calling ioctl(UFFDIO_WRITEPROTECT, wp=false)
right before ioctl(UFFDIO_UNREGISTER) for the user. So potentially it'll
make the unregister slower. From that pov it's a very slight abi change,
but hopefully nothing should break with this change either.
Regarding to the change itself - core of uffd write [un]protect operation
is moved into a separate function (uffd_wp_range()) and it is reused in
the unregister code path.
Note that the new function will not check for anything, e.g. ranges or
memory types, because they should have been checked during the previous
UFFDIO_REGISTER or it should have failed already. It also doesn't check
mmap_changing because we're with mmap write lock held anyway.
I added a Fixes upon introducing of uffd-wp shmem+hugetlbfs because that's
the only issue reported so far and that's the commit David's reproducer
will start working (v5.19+). But the whole idea actually applies to not
only file memories but also anonymous. It's just that we don't need to
fix anonymous prior to v5.19- because there's no known way to exploit.
IOW, this patch can also fix the issue reported in [1] as the patch 2 does.
[1] https://lore.kernel.org/all/20220811103435.188481-3-david@redhat.com/
Link: https://lkml.kernel.org/r/20220811201340.39342-1-peterx@redhat.com
Fixes: b1f9e87686 ("mm/uffd: enable write protection for shmem & hugetlbfs")
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
