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Tetsuo Handa 2d451ec01e profiling: remove profile=sleep support
commit b88f55389ad27f05ed84af9e1026aa64dbfabc9a upstream.

The kernel sleep profile is no longer working due to a recursive locking
bug introduced by commit 42a20f86dc ("sched: Add wrapper for get_wchan()
to keep task blocked")

Booting with the 'profile=sleep' kernel command line option added or
executing

  # echo -n sleep > /sys/kernel/profiling

after boot causes the system to lock up.

Lockdep reports

  kthreadd/3 is trying to acquire lock:
  ffff93ac82e08d58 (&p->pi_lock){....}-{2:2}, at: get_wchan+0x32/0x70

  but task is already holding lock:
  ffff93ac82e08d58 (&p->pi_lock){....}-{2:2}, at: try_to_wake_up+0x53/0x370

with the call trace being

   lock_acquire+0xc8/0x2f0
   get_wchan+0x32/0x70
   __update_stats_enqueue_sleeper+0x151/0x430
   enqueue_entity+0x4b0/0x520
   enqueue_task_fair+0x92/0x6b0
   ttwu_do_activate+0x73/0x140
   try_to_wake_up+0x213/0x370
   swake_up_locked+0x20/0x50
   complete+0x2f/0x40
   kthread+0xfb/0x180

However, since nobody noticed this regression for more than two years,
let's remove 'profile=sleep' support based on the assumption that nobody
needs this functionality.

Fixes: 42a20f86dc ("sched: Add wrapper for get_wchan() to keep task blocked")
Cc: stable@vger.kernel.org # v5.16+
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-14 13:58:47 +02:00
Documentation profiling: remove profile=sleep support 2024-08-14 13:58:47 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
arch x86/mm: Fix pti_clone_entry_text() for i386 2024-08-14 13:58:38 +02:00
block block: fix deadlock between sd_remove & sd_release 2024-08-03 08:54:24 +02:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: aead,cipher - zeroize key buffer after use 2024-07-11 12:49:04 +02:00
drivers s390/sclp: Prevent release of buffer in I/O 2024-08-14 13:58:47 +02:00
fs jbd2: avoid memleak in jbd2_journal_write_metadata_buffer 2024-08-14 13:58:46 +02:00
include profiling: remove profile=sleep support 2024-08-14 13:58:47 +02:00
init rust: SHADOW_CALL_STACK is incompatible with Rust 2024-08-11 12:47:24 +02:00
io_uring io_uring: fix io_match_task must_hold 2024-08-03 08:54:41 +02:00
ipc sysctl: treewide: drop unused argument ctl_table_root::set_ownership(table) 2024-08-11 12:47:13 +02:00
kernel profiling: remove profile=sleep support 2024-08-14 13:58:47 +02:00
lib lib/build_OID_registry: don't mention the full path of the script in output 2024-08-03 08:54:32 +02:00
mm mm/page_alloc: fix pcp->count race between drain_pages_zone() vs __rmqueue_pcplist() 2024-08-11 12:47:16 +02:00
net SUNRPC: Fix a race to wake a sync task 2024-08-14 13:58:47 +02:00
rust rust: kernel: require `Send` for `Module` implementations 2024-05-17 12:01:56 +02:00
samples work around gcc bugs with 'asm goto' with outputs 2024-02-23 09:24:47 +01:00
scripts kbuild: avoid build error when single DTB is turned into composite DTB 2024-08-03 08:54:36 +02:00
security apparmor: Fix null pointer deref when receiving skb during sock creation 2024-08-03 08:54:38 +02:00
sound Revert "ALSA: firewire-lib: operate for period elapse event in process context" 2024-08-11 12:47:25 +02:00
tools selftests/bpf: Fix send_signal test with nested CONFIG_PARAVIRT 2024-08-14 13:58:42 +02:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin() 2024-06-27 13:49:11 +02:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.rustfmt.toml rust: add `.rustfmt.toml` 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS pwm: Rename pwm_apply_state() to pwm_apply_might_sleep() 2024-06-12 11:12:24 +02:00
Makefile Linux 6.6.45 2024-08-11 12:47:28 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
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.