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Received Ethernet frames are assigned to first RX queue per default.
Based on EtherType Ethernet frames can be assigned to other RX queues.
This enables processing of real-time Ethernet protocols on dedicated
RX queues.
Add RX flow classification interface for EtherType based RX queue
assignment.
Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Support additional TX/RX queue pairs if dedicated interrupt is
available. Interrupts are detected by name in device tree.
Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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For multiple queues multiple interrupts shall be used. Therefore, rework
global interrupt to per queue interrupt.
Every interrupt name shall contain interface name and queue information.
To get a valid interface name, the interrupt request needs to by done
during open like in other drivers. Additionally, this allows the removal
of some initialisation checks in the interrupt handler.
Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Additional TX/RX queue pairs require dedicated interrupts. Extend
binding with additional interrupts.
Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Within SoCs like ZynqMP, FPGA logic can be connected to different kinds
of AXI master ports. Also cache coherent AXI master ports are available.
The property "dma-coherent" is used to signal that DMA is cache
coherent.
Add "dma-coherent" property to allow the configuration of cache coherent
DMA.
Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Sabrina Dubroca says:
============
This series completes extack support for state creation.
============
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
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Now that Clang's -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang
option is no longer required, remove it from the command line. Clang 16
and later will warn when it is used, which will cause Kconfig to think
it can't use -ftrivial-auto-var-init=zero at all. Check for whether it
is required and only use it when so.
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: linux-kbuild@vger.kernel.org
Cc: llvm@lists.linux.dev
Cc: stable@vger.kernel.org
Fixes: f02003c860d9 ("hardening: Avoid harmless Clang option under CONFIG_INIT_STACK_ALL_ZERO")
Signed-off-by: Kees Cook <keescook@chromium.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue
Tony Nguyen says:
====================
Intel Wired LAN Driver Updates 2022-09-28 (ice)
Arkadiusz implements a single pin initialization function, checking feature
bits, instead of having separate device functions and updates sub-device
IDs for recognizing E810T devices.
Martyna adds support for switchdev filters on VLAN priority field.
* '100GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue:
ice: Add support for VLAN priority filters in switchdev
ice: support features on new E810T variants
ice: Merge pin initialization of E810 and E810T adapters
====================
Link: https://lore.kernel.org/r/20220928203217.411078-1-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Zbynek reports that alx trips an rtnl assertion on resume:
RTNL: assertion failed at net/core/dev.c (2891)
RIP: 0010:netif_set_real_num_tx_queues+0x1ac/0x1c0
Call Trace:
<TASK>
__alx_open+0x230/0x570 [alx]
alx_resume+0x54/0x80 [alx]
? pci_legacy_resume+0x80/0x80
dpm_run_callback+0x4a/0x150
device_resume+0x8b/0x190
async_resume+0x19/0x30
async_run_entry_fn+0x30/0x130
process_one_work+0x1e5/0x3b0
indeed the driver does not hold rtnl_lock during its internal close
and re-open functions during suspend/resume. Note that this is not
a huge bug as the driver implements its own locking, and does not
implement changing the number of queues, but we need to silence
the splat.
Fixes: 4a5fe57e7751 ("alx: use fine-grained locking instead of RTNL")
Reported-and-tested-by: Zbynek Michl <zbynek.michl@gmail.com>
Reviewed-by: Niels Dossche <dossche.niels@gmail.com>
Link: https://lore.kernel.org/r/20220928181236.1053043-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Fix the following build errors:
arch/sparc/mm/srmmu.c: In function ‘smp_flush_page_for_dma’:
arch/sparc/mm/srmmu.c:1639:13: error: cast between incompatible function types from ‘void (*)(long unsigned int)’ to ‘void (*)(long unsigned int, long unsigned int, long unsigned int, long unsigned int, long unsigned int)’ [-Werror=cast-function-type]
1639 | xc1((smpfunc_t) local_ops->page_for_dma, page);
| ^
arch/sparc/mm/srmmu.c: In function ‘smp_flush_cache_mm’:
arch/sparc/mm/srmmu.c:1662:29: error: cast between incompatible function types from ‘void (*)(struct mm_struct *)’ to ‘void (*)(long unsigned int, long unsigned int, long unsigned int, long unsigned int, long unsigned int)’ [-Werror=cast-function-type]
1662 | xc1((smpfunc_t) local_ops->cache_mm, (unsigned long) mm);
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[ ... ]
Compile-tested only.
Fixes: 552a23a0e5d0 ("Makefile: Enable -Wcast-function-type")
Cc: stable@vger.kernel.org
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220830205854.1918026-1-bvanassche@acm.org
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Follow the advice of the Documentation/filesystems/sysfs.rst and show()
should only use sysfs_emit() or sysfs_emit_at() when formatting the value
to be returned to user space.
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/1664364860-29153-1-git-send-email-wangyufen@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Vladimir Oltean says:
====================
Add tc-taprio support for queueMaxSDU
The tc-taprio offload mode supported by the Felix DSA driver has
limitations surrounding its guard bands.
The initial discussion was at:
https://lore.kernel.org/netdev/c7618025da6723418c56a54fe4683bd7@walle.cc/
with the latest status being that we now have a vsc9959_tas_guard_bands_update()
method which makes a best-guess attempt at how much useful space to
reserve for packet scheduling in a taprio interval, and how much to
reserve for guard bands.
IEEE 802.1Q actually does offer a tunable variable (queueMaxSDU) which
can determine the max MTU supported per traffic class. In turn we can
determine the size we need for the guard bands, depending on the
queueMaxSDU. This way we can make the guard band of small taprio
intervals smaller than one full MTU worth of transmission time, if we
know that said traffic class will transport only smaller packets.
As discussed with Gerhard Engleder, the queueMaxSDU may also be useful
in limiting the latency on an endpoint, if some of the TX queues are
outside of the control of the Linux driver.
https://patchwork.kernel.org/project/netdevbpf/patch/20220914153303.1792444-11-vladimir.oltean@nxp.com/
Allow input of queueMaxSDU through netlink into tc-taprio, offload it to
the hardware I have access to (LS1028A), and (implicitly) deny
non-default values to everyone else. Kurt Kanzenbach has also kindly
tested and shared a patch to offload this to hellcreek.
v3 at:
https://patchwork.kernel.org/project/netdevbpf/cover/20220927234746.1823648-1-vladimir.oltean@nxp.com/
v2 at:
https://patchwork.kernel.org/project/netdevbpf/list/?series=679954&state=*
v1 at:
https://patchwork.kernel.org/project/netdevbpf/cover/20220914153303.1792444-1-vladimir.oltean@nxp.com/
====================
Link: https://lore.kernel.org/r/20220928095204.2093716-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The driver currently sets the PTCMSDUR register statically to the max
MTU supported by the interface. Keep this logic if tc-taprio is absent
or if the max_sdu for a traffic class is 0, and follow the requested max
SDU size otherwise.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The Port Time Gating Control Register (PTGCR) and Port Time Gating
Capability Register (PTGCAPR) have definitions in the driver which
aren't in line with the other registers. Rename these.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The &priv->si->hw construct dereferences 2 pointers and makes lines
longer than they need to be, in turn making the code harder to read.
Replace &priv->si->hw accesses with a "hw" variable when there are 2 or
more accesses within a function that dereference this. This includes
loops, since &priv->si->hw is a loop invariant.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Add support for configuring the max SDU per priority and per port. If not
specified, keep the default.
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The following patch will need to make this function also respond to
TC_QUERY_BASE, so make the processing more structured around the
tc_setup_type.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Our current vsc9959_tas_guard_bands_update() algorithm has a limitation
imposed by the hardware design. To avoid packet overruns between one
gate interval and the next (which would add jitter for scheduled traffic
in the next gate), we configure the switch to use guard bands. These are
as large as the largest packet which is possible to be transmitted.
The problem is that at tc-taprio intervals of sizes comparable to a
guard band, there isn't an obvious place in which to split the interval
between the useful portion (for scheduling) and the guard band portion
(where scheduling is blocked).
For example, a 10 us interval at 1Gbps allows 1225 octets to be
transmitted. We currently split the interval between the bare minimum of
33 ns useful time (required to schedule a single packet) and the rest as
guard band.
But 33 ns of useful scheduling time will only allow a single packet to
be sent, be that packet 1200 octets in size, or 60 octets in size. It is
impossible to send 2 60 octets frames in the 10 us window. Except that
if we reduced the guard band (and therefore the maximum allowable SDU
size) to 5 us, the useful time for scheduling is now also 5 us, so more
packets could be scheduled.
The hardware inflexibility of not scheduling according to individual
packet lengths must unfortunately propagate to the user, who needs to
tune the queueMaxSDU values if he wants to fit more small packets into a
10 us interval, rather than one large packet.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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IEEE 802.1Q clause 12.29.1.1 "The queueMaxSDUTable structure and data
types" and 8.6.8.4 "Enhancements for scheduled traffic" talk about the
existence of a per traffic class limitation of maximum frame sizes, with
a fallback on the port-based MTU.
As far as I am able to understand, the 802.1Q Service Data Unit (SDU)
represents the MAC Service Data Unit (MSDU, i.e. L2 payload), excluding
any number of prepended VLAN headers which may be otherwise present in
the MSDU. Therefore, the queueMaxSDU is directly comparable to the
device MTU (1500 means L2 payload sizes are accepted, or frame sizes of
1518 octets, or 1522 plus one VLAN header). Drivers which offload this
are directly responsible of translating into other units of measurement.
To keep the fast path checks optimized, we keep 2 arrays in the qdisc,
one for max_sdu translated into frame length (so that it's comparable to
skb->len), and another for offloading and for dumping back to the user.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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When adding optional new features to Qdisc offloads, existing drivers
must reject the new configuration until they are coded up to act on it.
Since modifying all drivers in lockstep with the changes in the Qdisc
can create problems of its own, it would be nice if there existed an
automatic opt-in mechanism for offloading optional features.
Jakub proposes that we multiplex one more kind of call through
ndo_setup_tc(): one where the driver populates a Qdisc-specific
capability structure.
First user will be taprio in further changes. Here we are introducing
the definitions for the base functionality.
Link: https://patchwork.kernel.org/project/netdevbpf/patch/20220923163310.3192733-3-vladimir.oltean@nxp.com/
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Co-developed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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After commit 09b5678c778f("tipc: remove dead code in tipc_net and relatives"),
struct distr_queue_item is not used any more and can be removed as well.
Signed-off-by: Yuan Can <yuancan@huawei.com>
Acked-by: Jon Maloy <jmaloy@redhat.com>
Link: https://lore.kernel.org/r/20220928085636.71749-1-yuancan@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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After commit 3226b158e67c ("net: avoid 32 x truesize under-estimation
for tiny skbs") we are observing 10-20% regressions in performance
tests with small packets. The perf trace points to high pressure on
the slab allocator.
This change tries to improve the allocation schema for small packets
using an idea originally suggested by Eric: a new per CPU page frag is
introduced and used in __napi_alloc_skb to cope with small allocation
requests.
To ensure that the above does not lead to excessive truesize
underestimation, the frag size for small allocation is inflated to 1K
and all the above is restricted to build with 4K page size.
Note that we need to update accordingly the run-time check introduced
with commit fd9ea57f4e95 ("net: add napi_get_frags_check() helper").
Alex suggested a smart page refcount schema to reduce the number
of atomic operations and deal properly with pfmemalloc pages.
Under small packet UDP flood, I measure a 15% peak tput increases.
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Suggested-by: Alexander H Duyck <alexanderduyck@fb.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Link: https://lore.kernel.org/r/6b6f65957c59f86a353fc09a5127e83a32ab5999.1664350652.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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To work around a misbehavior of the compiler's ability to see into
composite flexible array structs (as detailed in the coming memcpy()
hardening series[1]), use unsafe_memcpy(), as the sizing,
bounds-checking, and allocation are all very tightly coupled here.
This silences the false-positive reported by syzbot:
memcpy: detected field-spanning write (size 80) of single field "&n->sel" at net/sched/cls_u32.c:1043 (size 16)
[1] https://lore.kernel.org/linux-hardening/20220901065914.1417829-2-keescook@chromium.org
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Reported-by: syzbot+a2c4601efc75848ba321@syzkaller.appspotmail.com
Link: https://lore.kernel.org/lkml/000000000000a96c0b05e97f0444@google.com/
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/20220927153700.3071688-1-keescook@chromium.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The stmmac-axi-config subnode is present in multiple dwmac instance DTs,
document its content per snps,axi-config property description which is
a phandle to this subnode.
Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220927012449.698915-1-marex@denx.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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nlmsg_flags are full of historical baggage, inconsistencies and
strangeness. Try to document it more thoroughly. Explain the meaning
of the ECHO flag (and while at it clarify the comment in the uAPI).
Handwave a little about the NEW request flags and how they make
sense on the surface but cater to really old paradigm before commands
were a thing.
I will add more notes on how to make use of ECHO and discouragement
for reuse of flags to the kernel-side documentation.
Link: https://lore.kernel.org/r/20220927212306.823862-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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When copying a large file over sftp over vsock, data size is usually 32kB,
and kmalloc seems to fail to try to allocate 32 32kB regions.
vhost-5837: page allocation failure: order:4, mode:0x24040c0
Call Trace:
[<ffffffffb6a0df64>] dump_stack+0x97/0xdb
[<ffffffffb68d6aed>] warn_alloc_failed+0x10f/0x138
[<ffffffffb68d868a>] ? __alloc_pages_direct_compact+0x38/0xc8
[<ffffffffb664619f>] __alloc_pages_nodemask+0x84c/0x90d
[<ffffffffb6646e56>] alloc_kmem_pages+0x17/0x19
[<ffffffffb6653a26>] kmalloc_order_trace+0x2b/0xdb
[<ffffffffb66682f3>] __kmalloc+0x177/0x1f7
[<ffffffffb66e0d94>] ? copy_from_iter+0x8d/0x31d
[<ffffffffc0689ab7>] vhost_vsock_handle_tx_kick+0x1fa/0x301 [vhost_vsock]
[<ffffffffc06828d9>] vhost_worker+0xf7/0x157 [vhost]
[<ffffffffb683ddce>] kthread+0xfd/0x105
[<ffffffffc06827e2>] ? vhost_dev_set_owner+0x22e/0x22e [vhost]
[<ffffffffb683dcd1>] ? flush_kthread_worker+0xf3/0xf3
[<ffffffffb6eb332e>] ret_from_fork+0x4e/0x80
[<ffffffffb683dcd1>] ? flush_kthread_worker+0xf3/0xf3
Work around by doing kvmalloc instead.
Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko")
Signed-off-by: Junichi Uekawa <uekawa@chromium.org>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20220928064538.667678-1-uekawa@chromium.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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With commit 987f20a9dcce ("a.out: Remove the a.out implementation"), the
use of the special taso flag for alpha architectures in the linux_binprm
struct is gone.
Remove the definition of taso in the linux_binprm struct.
No functional change.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220929203903.9475-1-lukas.bulwahn@gmail.com
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git://anongit.freedesktop.org/drm/drm-intel into drm-fixes
- Restrict forced preemption to the active context (Chris)
- Restrict perf_limit_reasons to the supported platforms - gen11+ (Ashutosh)
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/YzXAkH1a32pYJD33@intel.com
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https://gitlab.freedesktop.org/agd5f/linux into drm-fixes
amd-drm-fixes-6.0-2022-09-29:
amdgpu:
- GC 11.x fixes
- SMU 13.x fixes
- DCN 3.1.4 fixes
- DCN 3.2.x fixes
- GC 9.x fix
- Fence fix
- SR-IOV supend/resume fix
- PSR regression fix
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220929144003.8363-1-alexander.deucher@amd.com
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git://anongit.freedesktop.org/drm/drm-misc into drm-fixes
Short summary of fixes pull:
* bridge/analogix: Revert earlier suspend fix
* bridge/lt8912b: Fix corrupt display output
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/YzWvHhaqHhYirn4L@linux-uq9g
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Pull coredump fix from Al Viro:
"Fix for breakage in dump_user_range()"
* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
[coredump] don't use __kernel_write() on kmap_local_page()
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No conflicts.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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This uses l2cap_chan_hold_unless_zero() after calling
__l2cap_get_chan_blah() to prevent the following trace:
Bluetooth: l2cap_core.c:static void l2cap_chan_destroy(struct kref
*kref)
Bluetooth: chan 0000000023c4974d
Bluetooth: parent 00000000ae861c08
==================================================================
BUG: KASAN: use-after-free in __mutex_waiter_is_first
kernel/locking/mutex.c:191 [inline]
BUG: KASAN: use-after-free in __mutex_lock_common
kernel/locking/mutex.c:671 [inline]
BUG: KASAN: use-after-free in __mutex_lock+0x278/0x400
kernel/locking/mutex.c:729
Read of size 8 at addr ffff888006a49b08 by task kworker/u3:2/389
Link: https://lore.kernel.org/lkml/20220622082716.478486-1-lee.jones@linaro.org
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sungwoo Kim <iam@sung-woo.kim>
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checkpatch does not point out that VM_BUG_ON() and friends should be
avoided, however, Linus notes:
VM_BUG_ON() has the exact same semantics as BUG_ON. It is literally
no different, the only difference is "we can make the code smaller
because these are less important". [1]
So let's warn on VM_BUG_ON() and other BUG variants as well. While at it,
make it clearer that the kernel really shouldn't be crashed.
As there are some subsystem BUG macros that actually don't end up crashing
the kernel -- for example, KVM_BUG_ON() -- exclude these manually.
[1] https://lore.kernel.org/r/CAHk-=wg40EAZofO16Eviaj7mfqDhZ2gVEbvfsMf6gYzspRjYvw@mail.gmail.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20220923113426.52871-3-david@redhat.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Linus notes [1] that the introduction of new code that uses VM_BUG_ON()
is just as bad as BUG_ON(), because it will crash the kernel on
distributions that enable CONFIG_DEBUG_VM (like Fedora):
VM_BUG_ON() has the exact same semantics as BUG_ON. It is literally
no different, the only difference is "we can make the code smaller
because these are less important". [2]
This resulted in a more generic discussion about usage of BUG() and
friends. While there might be corner cases that still deserve a BUG_ON(),
most BUG_ON() cases should simply use WARN_ON_ONCE() and implement a
recovery path if reasonable:
The only possible case where BUG_ON can validly be used is "I have
some fundamental data corruption and cannot possibly return an
error". [2]
As a very good approximation is the general rule:
"absolutely no new BUG_ON() calls _ever_" [2]
... not even if something really shouldn't ever happen and is merely for
documenting that an invariant always has to hold. However, there are sill
exceptions where BUG_ON() may be used:
If you have a "this is major internal corruption, there's no way we can
continue", then BUG_ON() is appropriate. [3]
There is only one good BUG_ON():
Now, that said, there is one very valid sub-form of BUG_ON():
BUILD_BUG_ON() is absolutely 100% fine. [2]
While WARN will also crash the machine with panic_on_warn set, that's
exactly to be expected:
So we have two very different cases: the "virtual machine with good
logging where a dead machine is fine" - use 'panic_on_warn'. And
the actual real hardware with real drivers, running real loads by
users. [4]
The basic idea is that warnings will similarly get reported by users
and be found during testing. However, in contrast to a BUG(), there is a
way to actually influence the expected behavior (e.g., panic_on_warn)
and to eventually keep the machine alive to extract some debug info.
Ingo notes that not all WARN_ON_ONCE cases need recovery. If we don't ever
expect this code to trigger in any case, recovery code is not really
helpful.
I'd prefer to keep all these warnings 'simple' - i.e. no attempted
recovery & control flow, unless we ever expect these to trigger.
[5]
There have been different rules floating around that were never properly
documented. Let's try to clarify.
[1] https://lkml.kernel.org/r/CAHk-=wiEAH+ojSpAgx_Ep=NKPWHU8AdO3V56BXcCsU97oYJ1EA@mail.gmail.com
[2] https://lore.kernel.org/r/CAHk-=wg40EAZofO16Eviaj7mfqDhZ2gVEbvfsMf6gYzspRjYvw@mail.gmail.com
[3] https://lkml.kernel.org/r/CAHk-=wit-DmhMfQErY29JSPjFgebx_Ld+pnerc4J2Ag990WwAA@mail.gmail.com
[4] https://lore.kernel.org/r/CAHk-=wgF7K2gSSpy=m_=K3Nov4zaceUX9puQf1TjkTJLA2XC_g@mail.gmail.com
[5] https://lore.kernel.org/r/YwIW+mVeZoTOxn%2F4@gmail.com
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20220923113426.52871-2-david@redhat.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Add missing devm_request_free_mem_region() to devres.rst.
It's introduced by commit 0092908d16c6 ("mm: factor out a
devm_request_free_mem_region helper").
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220927080215.1359979-1-yangyingliang@huawei.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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devm_irq_sim_init() has been changed to devm_irq_domain_create_sim()
in commit 337cbeb2c13e ("genirq/irq_sim: Simplify the API").
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220927083819.12484-1-yangyingliang@huawei.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Since commit b3ac04132c4b ("mm/rmap: Turn page_referenced() into
folio_referenced()") the page_referenced function name was modified,
so fix it up to use the correct one.
Signed-off-by: Vernon Yang <vernon2gm@gmail.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/20220926152032.74621-1-vernon2gm@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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The Code of Conduct interpretation does not reflect the current
practices of the CoC committee or the TAB. Update the documentation
to remove references to initial committees and boot strap periods
since it is past that time, and note that the this document
does serve as the documentation for the CoC committee processes.
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220926211149.2278214-1-kristen@linux.intel.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Now that building html docs with math expressions does not need texlive
packages, remove the note on the requirement in the "Sphinx Install"
section.
Instead, add sections of "Math Expressions in HTML" and "Choice of Math
Renderer".
Describe the effect of setting SPHINX_IMGMATH in the latter section.
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/a67e3279-6bc7-ee2c-2b49-9275252460b0@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Bring the description on when to use the Reported-by: tag found in
Documentation/process/5.Posting.rst more in line with the description in
Documentation/process/submitting-patches.rst: before this change the two
were contradicting each other, as the latter is way more permissive and
only states '[...] if the bug was reported in private, then ask for
permission first before using the Reported-by tag.'
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Link: https://lore.kernel.org/r/2fc7162dfb76e04da5ea903c9c170d913e735dad.1664372256.git.linux@leemhuis.info
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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After commit 22471e1313f2 ("kconfig: use a menu in arch/Kconfig to reduce
clutter"), the location of Kprobes is under "General architecture-dependent
options" rather than "General setup".
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Fixes: 22471e1313f2 ("kconfig: use a menu in arch/Kconfig to reduce clutter")
Link: https://lore.kernel.org/r/1663322106-12178-1-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Enable sram on vcn_4_0_2
Signed-off-by: Sonny Jiang <sonny.jiang@amd.com>
Reviewed-by: James Zhu <James.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
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Enable VCN DPG on GC11_0_1
Signed-off-by: Sonny Jiang <sonny.jiang@amd.com>
Reviewed-by: James Zhu <James.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
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scripting engine
A brown paper bag where -Wno-error=deprecated-declarations was added
from compiler output when the right thing is to add
-Wno-deprecated-declarations, fix it.
Fixes: 4ee3c4da8b1b9c22 ("perf scripting python: Do not build fail on deprecation warnings")
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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The top-level index.rst file is the entry point for the kernel's
documentation, especially for readers of the HTML output. It is currently
a mess containing everything we thought to throw in there. Firefox says it
would require 26 pages of paper to print it. That is not a user-friendly
introduction.
This series aims to improve our documentation entry point with a focus on
rewriting index.rst. The result is, IMO, simpler and more approachable.
For anybody who wants to see the rendered results without building the
docs, have a look at:
https://static.lwn.net/kerneldoc/
This time around I've rendered the pages using the "Read The Docs" theme,
since that's what everybody will get by default. That theme ignores the
directives regarding the left column, so the results are not as good there.
I have a series proposing a default-theme change in the works, but that's a
separate topic.
This is only a beginning; I think this kind of organizational effort has to
be pushed down into the lower layers of the docs tree itself. But one has
to start somewhere.
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Readers looking for user-oriented information may benefit from it.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Reviewed-by: David Vernet <void@manifault.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20220927160559.97154-8-corbet@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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These files describe part of the core API, but have never been converted to
RST due to ... let's say local oppposition. So, create a set of
special-purpose wrappers to ..include these files into a separate page so
that they can be a part of the htmldocs build. Then link them into the
core-api manual and remove them from the "staging" dumping ground.
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Reviewed-by: David Vernet <void@manifault.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20220927160559.97154-7-corbet@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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This one file should not really be in the top-level documentation
directory. core-api/ may not be a perfect fit but seems to be best, so
move it there. Adjust a couple of internal document references to make
them location-independent, and point checkpatch.pl at the new location.
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Joe Perches <joe@perches.com>
Reviewed-by: David Vernet <void@manifault.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20220927160559.97154-6-corbet@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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There is some useless boilerplate text that was added by sphinx when this
file was first created; take it out.
Reviewed-by: David Vernet <void@manifault.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20220927160559.97154-5-corbet@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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