tjh.dev
Linux kernel
============
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Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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To pick the changes in:
fb35d30fe5b06cc2 ("x86/cpufeatures: Assign dedicated feature word for CPUID_0x8000001F[EAX]")
e7b6385b01d8e9fb ("x86/cpufeatures: Add Intel SGX hardware bits")
1478b99a76534b6c ("x86/cpufeatures: Mark ENQCMD as disabled when configured out")
That don't cause any change in the tools, just silences this perf build
warning:
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/disabled-features.h' differs from latest version at 'arch/x86/include/asm/disabled-features.h'
diff -u tools/arch/x86/include/asm/disabled-features.h arch/x86/include/asm/disabled-features.h
Cc: Borislav Petkov <bp@suse.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When peeking an event, it has a short path and a long path. The short
path uses the session pointer "one_mmap_addr" to directly fetch the
event; and the long path needs to read out the event header and the
following event data from file and fill into the buffer pointer passed
through the argument "buf".
The issue is in the long path that it copies the event header and event
data into the same destination address which pointer "buf", this means
the event header is overwritten. We are just lucky to run into the
short path in most cases, so we don't hit the issue in the long path.
This patch adds the offset "hdr_sz" to the pointer "buf" when copying
the event data, so that it can reserve the event header which can be
used properly by its caller.
Fixes: 5a52f33adf02 ("perf session: Add perf_session__peek_event()")
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210605052957.1070720-1-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Olivier Langlois has been struggling with coredumps being incompletely written in
processes using io_uring.
Olivier Langlois <olivier@trillion01.com> writes:
> io_uring is a big user of task_work and any event that io_uring made a
> task waiting for that occurs during the core dump generation will
> generate a TIF_NOTIFY_SIGNAL.
>
> Here are the detailed steps of the problem:
> 1. io_uring calls vfs_poll() to install a task to a file wait queue
> with io_async_wake() as the wakeup function cb from io_arm_poll_handler()
> 2. wakeup function ends up calling task_work_add() with TWA_SIGNAL
> 3. task_work_add() sets the TIF_NOTIFY_SIGNAL bit by calling
> set_notify_signal()
The coredump code deliberately supports being interrupted by SIGKILL,
and depends upon prepare_signal to filter out all other signals. Now
that signal_pending includes wake ups for TIF_NOTIFY_SIGNAL this hack
in dump_emitted by the coredump code no longer works.
Make the coredump code more robust by explicitly testing for all of
the wakeup conditions the coredump code supports. This prevents
new wakeup conditions from breaking the coredump code, as well
as fixing the current issue.
The filesystem code that the coredump code uses already limits
itself to only aborting on fatal_signal_pending. So it should
not develop surprising wake-up reasons either.
v2: Don't remove the now unnecessary code in prepare_signal.
Cc: stable@vger.kernel.org
Fixes: 12db8b690010 ("entry: Add support for TIF_NOTIFY_SIGNAL")
Reported-by: Olivier Langlois <olivier@trillion01.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull cgroup fix from Tejun Heo:
"This is a high priority but low risk fix for a cgroup1 bug where
rename(2) can change a cgroup's name to something which can break
parsing of /proc/PID/cgroup"
* 'for-5.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup1: don't allow '\n' in renaming
Pull rdma fixes from Jason Gunthorpe:
"A mixture of small bug fixes and a small security issue:
- WARN_ON when IPoIB is automatically moved between namespaces
- Long standing bug where mlx5 would use the wrong page for the
doorbell recovery memory if fork is used
- Security fix for mlx4 that disables the timestamp feature
- Several crashers for mlx5
- Plug a recent mlx5 memory leak for the sig_mr"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
IB/mlx5: Fix initializing CQ fragments buffer
RDMA/mlx5: Delete right entry from MR signature database
RDMA: Verify port when creating flow rule
RDMA/mlx5: Block FDB rules when not in switchdev mode
RDMA/mlx4: Do not map the core_clock page to user space unless enabled
RDMA/mlx5: Use different doorbell memory for different processes
RDMA/ipoib: Fix warning caused by destroying non-initial netns
cgroup_mkdir() have restriction on newline usage in names:
$ mkdir $'/sys/fs/cgroup/cpu/test\ntest2'
mkdir: cannot create directory
'/sys/fs/cgroup/cpu/test\ntest2': Invalid argument
But in cgroup1_rename() such check is missed.
This allows us to make /proc/<pid>/cgroup unparsable:
$ mkdir /sys/fs/cgroup/cpu/test
$ mv /sys/fs/cgroup/cpu/test $'/sys/fs/cgroup/cpu/test\ntest2'
$ echo $$ > $'/sys/fs/cgroup/cpu/test\ntest2'
$ cat /proc/self/cgroup
11:pids:/
10:freezer:/
9:hugetlb:/
8:cpuset:/
7:blkio:/user.slice
6:memory:/user.slice
5:net_cls,net_prio:/
4:perf_event:/
3:devices:/user.slice
2:cpu,cpuacct:/test
test2
1:name=systemd:/
0::/
Signed-off-by: Alexander Kuznetsov <wwfq@yandex-team.ru>
Reported-by: Andrey Krasichkov <buglloc@yandex-team.ru>
Acked-by: Dmitry Yakunin <zeil@yandex-team.ru>
Cc: stable@vger.kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull x86 platform driver fixes from Hans de Goede:
"Assorted pdx86 bug-fixes and some hardware-id additions for 5.13.
The mlxreg-hotplug revert is a regression-fix"
* tag 'platform-drivers-x86-v5.13-3' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86:
platform/mellanox: mlxreg-hotplug: Revert "move to use request_irq by IRQF_NO_AUTOEN flag"
platform/surface: dtx: Add missing mutex_destroy() call in failure path
platform/surface: aggregator: Fix event disable function
platform/x86: thinkpad_acpi: Add X1 Carbon Gen 9 second fan support
platform/surface: aggregator_registry: Add support for 13" Intel Surface Laptop 4
platform/surface: aggregator_registry: Update comments for 15" AMD Surface Laptop 4
The function init_cq_frag_buf() can be called to initialize the current CQ
fragments buffer cq->buf, or the temporary cq->resize_buf that is filled
during CQ resize operation.
However, the offending commit started to use function get_cqe() for
getting the CQEs, the issue with this change is that get_cqe() always
returns CQEs from cq->buf, which leads us to initialize the wrong buffer,
and in case of enlarging the CQ we try to access elements beyond the size
of the current cq->buf and eventually hit a kernel panic.
[exception RIP: init_cq_frag_buf+103]
[ffff9f799ddcbcd8] mlx5_ib_resize_cq at ffffffffc0835d60 [mlx5_ib]
[ffff9f799ddcbdb0] ib_resize_cq at ffffffffc05270df [ib_core]
[ffff9f799ddcbdc0] llt_rdma_setup_qp at ffffffffc0a6a712 [llt]
[ffff9f799ddcbe10] llt_rdma_cc_event_action at ffffffffc0a6b411 [llt]
[ffff9f799ddcbe98] llt_rdma_client_conn_thread at ffffffffc0a6bb75 [llt]
[ffff9f799ddcbec8] kthread at ffffffffa66c5da1
[ffff9f799ddcbf50] ret_from_fork_nospec_begin at ffffffffa6d95ddd
Fix it by getting the needed CQE by calling mlx5_frag_buf_get_wqe() that
takes the correct source buffer as a parameter.
Fixes: 388ca8be0037 ("IB/mlx5: Implement fragmented completion queue (CQ)")
Link: https://lore.kernel.org/r/90a0e8c924093cfa50a482880ad7e7edb73dc19a.1623309971.git.leonro@nvidia.com
Signed-off-by: Alaa Hleihel <alaa@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Fix some spelling mistakes in comments:
hierarhcy ==> hierarchy
automtically ==> automatically
overriden ==> overridden
In absense of .. or ==> In absence of .. and
assocaited ==> associated
taget ==> target
initate ==> initiate
succeded ==> succeeded
curremt ==> current
udpated ==> updated
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull compiler attribute update from Miguel Ojeda:
"A trivial update to the compiler attributes: Add 'continue' keyword to
documentation in comment (from Wei Ming Chen)"
* tag 'compiler-attributes-for-linus-v5.13-rc6' of git://github.com/ojeda/linux:
Compiler Attributes: Add continue in comment
It causes mlxreg-hotplug probing failure: request_threaded_irq()
returns -EINVAL due to true value of condition:
((irqflags & IRQF_SHARED) && (irqflags & IRQF_NO_AUTOEN))
after flag "IRQF_NO_AUTOEN" has been added to:
err = devm_request_irq(&pdev->dev, priv->irq,
mlxreg_hotplug_irq_handler, IRQF_TRIGGER_FALLING
| IRQF_SHARED | IRQF_NO_AUTOEN,
"mlxreg-hotplug", priv);
This reverts commit bee3ecfed0fc ("platform/mellanox: mlxreg-hotplug: move
to use request_irq by IRQF_NO_AUTOEN flag").
Signed-off-by: Mykola Kostenok <c_mykolak@nvidia.com>
Acked-by: Vadim Pasternak <vadimp@nvidia.com>
Link: https://lore.kernel.org/r/20210603172827.2599908-1-c_mykolak@nvidia.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
The value mr->sig is stored in the entry upon mr allocation, however, ibmr
is wrongly entered here as "old", therefore, xa_cmpxchg() does not replace
the entry with NULL, which leads to the following trace:
WARNING: CPU: 28 PID: 2078 at drivers/infiniband/hw/mlx5/main.c:3643 mlx5_ib_stage_init_cleanup+0x4d/0x60 [mlx5_ib]
Modules linked in: nvme_rdma nvme_fabrics nvme_core 8021q garp mrp bonding bridge stp llc rfkill rpcrdma sunrpc rdma_ucm ib_srpt ib_isert iscsi_tad
CPU: 28 PID: 2078 Comm: reboot Tainted: G X --------- --- 5.13.0-0.rc2.19.el9.x86_64 #1
Hardware name: Dell Inc. PowerEdge R430/03XKDV, BIOS 2.9.1 12/07/2018
RIP: 0010:mlx5_ib_stage_init_cleanup+0x4d/0x60 [mlx5_ib]
Code: 8d bb 70 1f 00 00 be 00 01 00 00 e8 9d 94 ce da 48 3d 00 01 00 00 75 02 5b c3 0f 0b 5b c3 0f 0b 48 83 bb b0 20 00 00 00 74 d5 <0f> 0b eb d1 4
RSP: 0018:ffffa8db06d33c90 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff97f890a44000 RCX: ffff97f900ec0160
RDX: 0000000000000000 RSI: 0000000080080001 RDI: ffff97f890a44000
RBP: ffffffffc0c189b8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000300 R12: ffff97f890a44000
R13: ffffffffc0c36030 R14: 00000000fee1dead R15: 0000000000000000
FS: 00007f0d5a8a3b40(0000) GS:ffff98077fb80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555acbf4f450 CR3: 00000002a6f56002 CR4: 00000000001706e0
Call Trace:
mlx5r_remove+0x39/0x60 [mlx5_ib]
auxiliary_bus_remove+0x1b/0x30
__device_release_driver+0x17a/0x230
device_release_driver+0x24/0x30
bus_remove_device+0xdb/0x140
device_del+0x18b/0x3e0
mlx5_detach_device+0x59/0x90 [mlx5_core]
mlx5_unload_one+0x22/0x60 [mlx5_core]
shutdown+0x31/0x3a [mlx5_core]
pci_device_shutdown+0x34/0x60
device_shutdown+0x15b/0x1c0
__do_sys_reboot.cold+0x2f/0x5b
? vfs_writev+0xc7/0x140
? handle_mm_fault+0xc5/0x290
? do_writev+0x6b/0x110
do_syscall_64+0x40/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Fixes: e6fb246ccafb ("RDMA/mlx5: Consolidate MR destruction to mlx5_ib_dereg_mr()")
Link: https://lore.kernel.org/r/f3f585ea0db59c2a78f94f65eedeafc5a2374993.1623309971.git.leonro@nvidia.com
Signed-off-by: Aharon Landau <aharonl@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This patch effectively reverts the commit a3e72739b7a7 ("cgroup: fix
too early usage of static_branch_disable()"). The commit 6041186a3258
("init: initialize jump labels before command line option parsing") has
moved the jump_label_init() before parse_args() which has made the
commit a3e72739b7a7 unnecessary. On the other hand there are
consequences of disabling the controllers later as there are subsystems
doing the controller checks for different decisions. One such incident
is reported [1] regarding the memory controller and its impact on memory
reclaim code.
[1] https://lore.kernel.org/linux-mm/921e53f3-4b13-aab8-4a9e-e83ff15371e4@nec.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reported-by: NOMURA JUNICHI(野村 淳一) <junichi.nomura@nec.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: Jun'ichi Nomura <junichi.nomura@nec.com>
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